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Archive for the 'GPS' Category Page 2 of 8

Map Point Slopes And Directions With Rocklogger

Application Name: Rocklogger

Description: Map slopes and which direction they’re facing.

Publisher’s website: RockGecko

Cost: Free evaluation version limits you to 3 measurements every two minutes; $9.22 fee unlocks this restriction.

Version/date reviewed: v.1.01  /  3-27-11

Phone/OS: Droid X / Android 2.2


Android Market (mobile app only)
Android Market (browser)

A while back, I reviewed eGeo Compass, an app that maps slope and slope direction. The primary use is for geological mapping, but it could be used by anyone who has similar mapping needs (geomorphologists, archaeologists, gardeners, etc.). I thought eGeo Compass was pretty good, but the demo version was limited in functionality, and the registered version was a bit expensive at $13. Rocklogger offers the same basic functionality, the free version does more, and the registered version is cheaper, but it has some drawbacks as well.


App starts with the barest of screens. Tapping on Start new traverse brings up the option to name the data file, and also associate additional information. Unlike eGeo Compass, the free version of Rocklogger will let you export data in CSV format for use in mapping programs. If you’ve already stored a data file, you can also select it, and append new data points.


In measurement mode, the app will fire up the GPS to get your current position, and then display your current coordinates, along with your choice of three kinds of measured data:

  • Dip angle and direction: The slope in degrees, and the compass direction of that slope (you can choose true or magnetic direction)
  • Dip/strike: Commonly used in geological mapping. Dip is as above, but strike represents the orientation at which a geological strata intersects the ground surface; usually it’s 90 degrees less than the dip direction.
  • Magnetic field mode: Measures and records the magnetic magnitude vectors (XYZ), and the absolute magnitude

When you’re ready to make a measurement, lay the phone on the surface you want to measure, oriented so that the long axis of the phone (up/down) lies along the steepest slope).


Tapping on the Plane Type dropdown brings up a preprogrammed list of geological features you can assign to the point. However, you can add your own types (including non-geological ones), and subtract ones currently on the list, customizing it to your own requirements. The Settings section lets you reset this to the default. The Setttings section also implies that the app can save Rock Type input and let you choose from suggestions, but I couldn’t get that to work, possibly because I’m not using the default Android keyboard.

Pressing the Save incl. sensors button saves your current position and the measured data into the current data file; Save excl. sensors saves only your current position. You can set the app to require a long press to save data, to prevent accidental data recording. The evaluation version limits you to no more than three measurements in two minutes; the registered version allows unlimited measurements within any time frame.



Use the Back button to stop measuring, and bring you back to the startup screen; there now should be a listing for the new data file. Tapping the listing for that file name brings up the option to add more points, delete it, email it (useful for backup in the field, or exporting it to your computer for additional analysis), or open it in a compatible app for viewing/editing.

Other issues: Unlike eGeo, Rocklogger doesn’t currently have the option in either the free or paid version to plot recorded data in a Google Maps view, though the author indicates this is coming. Having latitude/longitude displayed in degree-minute-seconds, without the option to view it in decimal degrees, is annoying; fortunately, positions are saved in decimal degrees in the data file.

The biggest issue for me is that, unlike eGeo,  you have to have the phone aligned so that its long axis lies along the direction of steepest slope, in order to get an accurate measurement. The app really needs to be set up so that it will automatically determine the direction and magnitude of steepest slope automatically, regardless of which way the phone is laid on the surface; that would not only improve accuracy, but speed up measurement time. I’ll monitor the app to see if this is implemented.

Final thoughts: I started out biased towards Rocklogger because its evaluation version allows data recording and export; you need eGeo Compass’s registered version to enable that. I do like the additional recording options, and multiple data inputs, especially the customizable dropdown. And unlike eGeo, you have the option to record the true direction, not just magnetic. But Rocklogger’s requirement that you have the phone oriented along the direction of steepest slope is a dealbreaker for me; it reduces accuracy, and slows down the overall recording time. If this were fixed, I’d give the edge to Rocklogger; but as is, eGeo Compass is currently the better app.

Locus, A GPS Mapping Application – Part III: Tracks, Waypoints And Miscellaneous

The final part of my review of the Locus map app for Android; here are links to Part I: Interface, and Part II: Maps.

The first thing you need to know about waypoints in Locus is that the program insists you assign them into named Categories; especially noticeable the first time you try to create one. I resented this initially, but have since decided that requiring this kind of categorization/organization is a really good idea. Waypoints can be added using the Points manager, normally accessible in the right toolbar.


After choosing a Category, you get the waypoint list for that category, along with additional options at the bottom. From left to right, they are:

  • “+” – Create a new waypoint. You’ll be given the choice of your current location, the current map center, an address, coordinates, or (if you have the optional Locus Contacts free plugin), one of the contacts in your address book. Tip: If you want to use map center, you should turn off the “center map on GPS location” button (left button on bottom toolbar), otherwise the map can pop back to your current location. Then scroll to the location you want to place the waypoint, and bring up the Points manager.
  • Check mark – Selects/deselects all waypoints. Checked waypoints are visible on the map, unchecked waypoints aren’t. You can also turn on/off individual waypoint display by tapping directly on the checkbox.
  • Arrowed circle – Refreshes the list
  • Boxes with down arrow – Sorts the waypoint list by name or distance from your current location
  • “Grouped” boxes – Lets you filter waypoints by icon
  • Trash can – Deletes selected waypoints


Tapping on a waypoint brings up more options:

  • Plot it on a map
  • Navigate to it
  • Edit/delete it
  • Send it to a navigation app (like Google’s Navigation); bring up the Google Street View if available; share it with compatible app; load it into either Locus’s built-in compass, or a compatible third-party app like GPS Status.


When you add a waypoint with the “+” control, you’re only given the option to name it (default is coordinates). But once recorded, you can go back and assign additional info to the waypoint, including standard stuff like a description and custom icon; plus,  non-standard stuff like taking a photo at that location and assigning it to the waypoint, or reverse-geocoding the nearest address based on the waypoint’s coordinates. Not sure how well the Photo feature works – on at least one occasion, a photo seemed to become “disassociated” with its waypoint (may have just been a random glitch). Reverse geocoding, on the other hand, worked perfectly, though this will require an active data connection. You’ll get the same screen when you edit an existing waypoint.



There’s a reasonably healthy default choice of icon graphics, but the app author describes a simple process by which you can use your own icon graphics for waypoints.


Finally, the author has recently added an augmented reality (AR) plugin that will superimpose a waypoints name/icon and “radar screen” on your Android unit’s camera view. My screenshot utility doesn’t capture the camera view, but just imagine a real-world view substituted for the white above. The radar screen shows the waypoint, but it’s so small and indistinct that it’s difficult to pick out. The Free version limits you to one minute of AR view; the $5.50 Pro version makes this unlimited.


For tracks, you have two options: either record your current movements as a track, or draw a track on the map screen. Both options are accessible from the right toolbar. If you choose to record your movements as a track, you’ll get a new toolbar at the bottom that lets you Start/Pause/Stop track recording …



or pull up an info window with current track statistics.


By default, tracks are saved with the current date and time, and there’s no way to change that immediately. However, if you go to the Data manager above (accessible from the top toolbar), you’ll be given the option to manage/edit your tracks. This Data manager also lets you create/edit/delete categories, gives you direct access to the Point manager for handling waypoints, and lets you Import/Export data in GPX or KML format. If you choose Tracks …


You’ll get a list of all the tracks stored in the app. Unlike waypoints, tracks aren’t assigned to a mandatory user-definable category, but are instead assigned a Locus-specific category that you can change. The controls at the bottom are the same as for waypoints, except for the missing “Add” option, not relevant here. Checking/unchecking a track determines whether it’s visible or not on the map display. Tapping on a track name brings up options to show a stats screen, export it directly as a GPX or KML file, show it on the map, delete it, or edit it …



One of the biggest advantages of Locus over OruxMaps is the customizability of waypoint icons and track colors. OruxMaps only has one waypoint icon, and while you can adjust the overall track color and width, you can’t specify different colors/widths for different tracks. Locus starts out with more waypoint icons, lets you add your own …


and also lets you specify different colors and widths for individual tracks, making them easier to identify on-screen.


The right toolbar also has an “Add track” button that lets you draw a track on screen, and then save it. Pressing this button brings up another toolbar to help with this function. The “+” button adds a track point at the current center map position, and the “-“ button removes the last track point added; the green check finishes the process and saves the track, while the red “x” aborts it. The center button, with the “right turn” logo, is interesting. If you specify two points on a track, the start and stop, then press this button …


… you’ll be given the option to automatically generate a routed track between those two points, for various forms of transportation. When you choose the desired transport …


You’ll see the route plotted, along with the direct-line connecting the start/stop; saving the track will only save the routed track, not the direct line.

Other issues: Apart from an occasionally-stubborn Bluetooth GPS connection, which could be resolved (see Part I), didn’t have any serious problems with the app.

Final thoughts: There’s no question that Locus is an outstanding Android map app. It works as it should, the interface is clean, map selection is good, and feature set is solid. In some aspects, like track/waypoint management, it’s vastly superior to OruxMaps; on the flip side, OruxMaps has a more customizable interface, and it’s easier to add additional online map sources to it. The one feature where OruxMaps is clearly superior to Locus is in your ability to add your own digital map imagery for viewing in OruxMaps; this is a feature I need all the time, and one not currently well-supported in Locus. Fortunately, with free/cheap versions of both apps, I don’t have to choose; I can see myself switching back and forth between the different apps on a regular basis, depending on what my current needs are. You’d be crazy not to have at least the free version of Locus on your Android unit (OruxMaps, too), and probably ultimately coughing up the $5.50 Pro registration fee to get rid of the ads.

Locus, A GPS Mapping Application – Part II: Maps

Continuing on with my review of the Locus GPS mapping app for Android (Part I on the interface is here), today is map day. Locus has a strong selection of standard online map sources, roughly 30 vs. roughly about 20 for OruxMaps. Some are worldwide, others regional. These mapsets currently include:

  • Google Maps: Road, Aerial, Hybrid, Terrain, Korea
  • OpenStreetMap” Classic, Cycle, Transport, Osmarender, OpenPiste
  • OVI-Nokia map:Classic, Satellite, Terrain (Locus is the only app I’ve seen so far with these useful mapsets)
  • Yahoo: Classic, Satellite
  • Bing: Road, Hybrid, London A-Z, OS Maps
  • OSM-regional: UMP-pcPL, Hike&Bike
  • Freemap (Slovakia): Car, Turistic, Cyclo, Aerial
  • Yandex (East Europe): Classic, Satellite
  • Eniro (North Europe): Classic, Aerial, Nautical, Hybrid
  • MyTopo (USA): 1:24K topographic maps
  • Outdoor Active (Germany, Austria, South Tyrol)
  • Statkaart (Norway): Topo, Raster
  • Maps+ (Switzerland): Topography, Terrain
  • NearMap (Australia): PhotoMap, StreetMap, Terrain


While there is a reasonable amount of overlap in mapsets between the two, each one also has unique mapsets as well. For US users, the big difference is that Locus comes with the MyTopo USGS 1:24K topographic mapset built in, while OruxMaps doesn’t. You can add Terraserver topo maps to OruxMaps (more on this in a bit), but the MyTopo set is of higher quality, and some areas are more up-to-date.


The list of available online maps can be brought up with the map manager button, in the upper right of the main map screen. You’ll get a list of available online mapsets:


Mapsets are organized into groups by source, a better system than OruxMaps’ sequential list of all maps. If you tap on a source name, like Google …



… you’ll get a subset listing of all the available maps from that source. Tap on the map type to go back to the map view, and load that selected mapset. The listing scrolls horizontally, so if you can’t see the desired mapset, tap and drag the listing left or right to access it.

First time I tried using Locus in the field, I was shocked at how many mapsets I was unable to download, despite having a good cellular connection. Then I explored the Settings section; under the Map subsection of Settings, you’ll find  a setting called “Offline mode”. If this is checked, which appears to be the default, maps can only be downloaded to your unit when you have a WiFi Internet connection. This protects you from being surprised with massive data overage charges from your cellular provider if you don’t have an unlimited data plan; my plan is unlimited, so I left this unchecked, and all mapsets now downloaded properly.

As online maps are downloaded, either from a WiFi or cellular connection, they are automatically cached so that you don’t have to repeatedly download them. I presume the size of the cache is limited, and that older maps are deleted automatically, but I wasn’t able to find out this info. For longer-term storage of mapsets, and avoiding large data downloads over cellular connections, Locus lets you create mapsets from download data, and then load them as needed into the app.


To access this function, go to the “Download map” tab in the map manager. You’ll have several options for selecting the area you want maps for:

  • This screen – Downloads maps for the area currently visible in the main map screen. You’ll want to zoom in/out first to your desired area.


  • Select area – Choose a subset of the current map area by clicking and dragging; press on the green check button at the bottom to approve the selection, or the red x button to clear it and select a different area. You can zoom in/out in this view, but if you haven’t already selected the desired general area first, new map data will not be loaded in as you zoom in/out.
  • By state – Downloaded predefined areas. By “state”, this means “country”, not “US state” or other subregions. Fine for smaller countries at lower zoom levels, not great for larger countries.



  • By path – This is pretty slick. Select this option, and get the map screen, with a new toolbar near the bottom. Click the “+” sign to add a point at the center of the screen, then drag the map to the next location and add another point. Locus will define an area around that point for which it will download maps, and show that as a purple overlay. You can set the width of the area with the slider at the top, and also tap-and-drag points to adjust them. The “-“ sign removes the last point, while the red x deletes all points. When done, tap the green check box. Be sure to disable the button at the lower-right, as otherwise the map will keep popping back to your current GPS location.
  • Select POIs – If you have a set of waypoints loaded into a category (more on this in the next post), Locus can use those to define an area for maps to be downloaded for. Nice, but I wish there were a comparable option for tracks as well, similar to the “By path” option, but loadable from a GPX file.


Once you’ve made any of your area selections, you’ll get a screen with the available zoom levels for that map; you need to choose at least one. You can choose more, but it will make the map filesize larger; maximum allowable filesize is 2 GB. The total map size and tile count is shown at top right, and you’ll also see a preview of the highest zoom level maps at right. Label the mapset file using the text box at the top.


Tapping “Change type” to choose the type/location for the downloaded map files. You can either put the map tiles into the standard online map cache, create a new separate mapset, or add maps to a pre-existing mapset of the same type. I usually use “Separate map”, since I think it will minimize complications, but that’s just a guess on my part. Once you’ve selected a map type, you go back to the zoom level screen; tapping OK starts the download process. This is usually best done with a WiFi connection, as that will be much faster, and won’t count against any cellular data quotas.



Once complete, the new mapset will appear in a listing under the “User maps” tab; just tap on the mapset you want to select it. Generally, these maps work fine, but I sometimes noticed when scrolling the map that tiles would appear and then disappear for no discernible reason. However, when using the maps in general GPS navigation mode, this didn’t seem to be a problem.

As with OruxMaps, you can also create mapset files from online map sources with the free Mobile Atlas Creator software, setting Big Planet / RMaps SQLite as the output format; the app author has more info here.

So far, Locus is superior to OruxMaps in handling online/offline maps. But it falls short in two major areas:

– Adding new online map sources is more complicated in Locus than OruxMaps (although neither is easy). There’s a post at the Locus forum on the process, but I couldn’t find any actual working examples. In contrast, OruxMaps offers a sample wms_services.xml file to get you started, which adds Terraserver US topographic maps to the list of available maps, and the OruxMaps forum has more working examples.

– OruxMaps has a stand-alone desktop application that can convert georeferenced raster image files, like GeoTiffs and OziExplorer map files, into an OruxMaps-compatible mapset. There is no general tool like that for Locus; there’s a mention in the forum of an old utility that can convert OziExplorer map files, but the format it creates may be deprecated soon in Locus. And it doesn’t look like the utility program mapc2mapc currently creates Locus-compatible map files, either. So there isn’t currently a good way to get your own maps into a Locus-compatible format, and that’s a big drawback for me.

Coming up in part III – tracks and waypoints in Locus.

Locus, A GPS Mapping Application – Part I: Interface

Application Name: Locus Free

Description: Display online/offline maps for your position; GPS track/waypoint display and recording; compass; more.

Publisher’s website: Locus

Cost: Free ad-support version; Pro version ($5.50) removes ads, and add some minor additional functionality.

Version/date reviewed: v.0.9.28  /  3-15-11

Phone/OS: Droid X / Android 2.2


Android Market (mobile app only)
Android Market (browser)

I’ve reviewed two other apps that convert your Android unit into the functional equivalent of a handheld GPS unit. TrekBuddy I was less than overwhelmed with; OruxMaps I found to be terrific. I’ll spoil the surprise conclusion here, and say that Locus is not only closer to OruxMaps in quality than TrekBuddy, but gives OruxMaps a run for its money in some respects. In this multi-day review, I’ll compare Locus’s functionality to OruxMaps as appropriate. As with OruxMaps, Locus has so many features that I can’t cover them all, even over the next few days; look at the program’s website, and explore the Settings section, for more info on all of its functionality.



The basic interface for Locus has three toolbars at top, right, and bottom. Unlike OruxMaps, where all toolbars are fully customizable, only the right toolbar in Locus can be modified, and only by checking/unchecking pre-defined options. There are five functions available on the top toolbar. They are:


– An “info” icon, which brings up links to “About application”, a simplified basic guide to using the app, an incomplete online manual viewed in your browser, the version history, and a list of additional apps that can invoke Locus as a helper app.


– Title bar options: tapping on the title bar lets you choose what’s displayed there. In the picture below, coordinates was selected for display in the title bar. One drawback of Locus compared to OruxMaps is that the number of data fields displayed onscreen with the map is far more limited in Locus.


– A GPS icon, which brings up the GPS status screen, with options to turn the GPS and compass on/off to conserve power.


– A data manager, which lets you view tracks/points, import/export data (GPX/KML formats supported), and manage categories. Locus requires you to specify a category label in which to save points and tracks; while I found this annoying at first, I now see the value of forcing you to organize your data by label.


– A map manager, for selecting and managing online/offline maps (more on this later)



Access the right-toolbar options by the Android Menu button, then selecting “Set right panel”; this screen also gives you several other options, most of which can also be assigned to the right toolbar.


The available right-toolbar functions are:

  • Search in POI: This is a saved waypoint search function; there is no general POI database in this app.
  • Move Map: Instantly move the display to an entered address or latitude/longitude.
  • Points: A waypoint list/manager (MOTL, more on this later)
  • Track record: Brings up another toolbar for recording tracks (MOTL)
  • Parking (BETA): Record your current parking spot, with options to set an alarm (useful for timed parking meters), and taking a photo of the location:


  • Share: Lets you send the current map center coordinates, or a screenshot of the current map display, to email, Facebook, SMS, etc.
  • Add new route: Bit misnamed, as it lets you create a new track in the map display; a “route” is a sequential collection of waypoints, which Locus doesn’t seem to have support for. MOTL
  • Compass: Option to switch to compass view, which includes guide information if you’ve selected a POI/waypoint as your destination:


The compass has a long settling time, so it will take a few seconds for the “needle” to move to the current direction. I’d prefer the option to manually adjust this sensitivity, but it’s not too bad. What is bad is that it shows the magnetic direction, not the true direction, as OruxMaps does. I wish I could mandate that every compass app for Android  either have true direction as the only option, or have it as the default with magnetic direction as an option. For many areas, the two will be similar, but in some areas the difference is substantial; where I live, there’s an eleven-degree difference between true and magnetic directions. Hope this gets fixed in Locus in the near future. Now fixed; there’s a new Sensors menu in the Setting that lets you choose True direction (default) or magnetic, and adjust the sensitivity of the compass.



The bottom toolbar has five functions. When the first button is active (as above), and the GPS is on, the map will automatically scroll to your current location. If you tap and drag the map to view a different location while this button is active, it will automatically “pop you back” to your current location in a few seconds.


The second button is a zoom lock/unlock button. When it’s off, you can only zoom in to the native resolution of the map image (or double that, if you turn on “Double sized resolution” in Settings => Map). When it’s engaged, as above …


… you can zoom in well past the native resolution; the above picture isn’t even at the full zoom available, since that would just look like a jumble of pixels.


The third button lets you choose a direction option. “Rotate map” will spin the map so that the direction you’re facing, or moving in, is at the top. This mode drives me nuts as it tends to swing around wildly, so I usually leave it off.


“Show view” displays a “field of view” indicator when you’re standing still, as above. When you’re in motion, the view changes to a triangle/arrow that points in the direction you’re currently moving. Since Locus currently uses magnetic directions, this can be a bit off from the true field of view.

This control is also useful for restoring the map to “North at top”. In the default mode, Locus supports advanced multi-touch, which lets you rotate the map view by dragging two fingers on the screen in different directions. This also drives me nuts, as sometimes when I want to only zoom in or out, I wind up rotating the map; using this control pops the map back to a normal orientation. You can turn off advanced multi-touch in the settings section, as I have.

The toolbars are partially transparent, and fairly small, so I usually leave them all turned on. However, the Settings section allows you to set any, or all, of the toolbars to fade away after a few seconds; tap twice on the screen to make them visible again.

One final topic, peripheral to the interface. Like OruxMaps, Locus has the option to use an external Bluetooth GPS receiver to obtain position, in place of the built-in GPS receiver; this can be specified in the settings section. This has some major advantages for both battery life and position accuracy. Unlike OruxMaps, though, I was actually able to get this Bluetooth connection to work in Locus, though it took some effort. Android’s Bluetooth support is a bit flaky, and it can take multiple attempts to achieve a successful connection. If the first Bluetooth connection attempt doesn’t work, and you’ll get an error message to that effect, go to the GPS status page, and turn GPS off and then on again. It may take 3-6 attempts, but eventually you do get a working connection to your Bluetooth GPS receiver. The application can also use Bluetooth GPS via proxy apps like Bluetooth GPS, which replace the built-in GPS receiver position for all apps.

Tomorrow: A look at maps in Locus.

Map Ship Information With MarineTraffic

Application Name: MarineTraffic.Com

Description: View marine ship traffic anywhere in the world; monitor ships; get port information.

Publisher’s website: MarineTrafic

Cost: Free

Version/date reviewed: v.0.9.3  /  3-8-11

Phone/OS: Droid X / Android 2.2


Android Market (mobile app only)
Android Market (browser)

If you live by the water, and want to know what ship is passing by, or if you’re just generally interested in matters nautical, MarineTraffic for Android is a must-have app.


The app starts out with a default view of marine traffic in the Eastern Mediterranean, and not much else on-screen to let you know what to do next. Triangles mark ships in motion, with the “pointy” end showing which way it’s going. Large diamonds indicate anchored/moored ships, while small ones show navigation aids. The colors indicate what kind of ship/craft it is (more on this later). It’s a standard Google Maps interface, so you can pinch to zoom, and pan to different areas.


Zoom out far enough, and you’ll find the grid areas where there’s information for ships; notice it includes Great Lakes and Mississippi River traffic information as well.


Tap on a green grid square, and you’ll be zoomed in closer to that area. You can then zoom in closer to any desired area for more information.


Here’s the entry to New York City’s harbor area; most of the markers are large diamonds, indicating anchored/moored ships. If you tap on the blue moving marker near the bottom …


You’ll bring up multiple options for additional data.


Vessel’s Details brings up full information about the vessel, including size/weight, current speed/position/course, and its schedule. If photos are available, you can view those (also available from the Show Photos option), but you can also upload a picture of your own.



Select Show Track, and see where the ship has been recently; based on the track above, and the schedule in the Details section, I’m guessing this is a sightseeing cruise boat.  Choosing Add To My Fleet “bookmarks” the vessel so that you can find it again.


From the app’s menu, choose Options to get a listing of vessel types and their color codes. You can choose not to show specific types by unchecking the box; additional options include displaying vessel names on the map, and switching to an aerial image instead of a map.


The Ports menu lets you select a world port for more information. Click on the “globe” icon to go to the map view centered on that port; click on the “magnifier” to get details about the port, and recent/upcoming arrivals and departures.

Additional options on the Menu:

  • Vessels – Search for a vessel by name, then find it on the map
  • Near Me – Fires up your GPS, and shows you the view near your location. If you’re outside of a marine area, you’ll just get a black screen.
  • More – Fast access to your My Fleet bookmarks, About the app, and a quick zoom out to a World Map view.
  • Areas – General marine areas by name (e.g. Baltic Sea, Japan, Ligurian Sea, etc.). Tap on a name, and go to that area in the map view; select a green grid square to zoom in closer.

Other issues: None; no problems.

Final thoughts: Pretty much a model of what this kind of data app should be like. Obviously only for those interested in maritime traffic, but if you are, a must-have.

PS There’s an iPhone version as well, and a general mobile website; the main website is also worth a look if you’re at a computer.

HT to Goya Bauwens for alerting me to the app.

Graphic Local Elevation Displays With AltitudeProfiler

Application Name: AltitudeProfiler

Description: Displays elevation profile graph in one compass direction, graphic display in all directions.

Publisher’s website: AndroidPit

Cost: Free, but with daily data limit; paid version gives you data priority, and supports the program.

Version/date reviewed: v.1.02  /  2-28-11

Phone/OS: Droid X / Android 2.2


Android Market (mobile app only)
Android Market (browser)

Altitude Profiler downloads local elevation data, and plots/displays it in several different ways.


Main screen displays local coordinate data and heading at the top. In the data box are:

  • True heading (not magnetic – yay!)
  • Magnetic declination at your location (?N)
  • The pitch angle and percentage slope (“/”); lay the phone flat on a surface to get its slope.
  • The view rotation angle (“R”), showing the twist angle of the phone
  • Latitude, longitude and elevation at your current location.

The slider sets the distance over which elevation data will be downloaded and displayed. Default is 6 km, and unless you have a really good reason, you should leave it there, or set it even lower. While the app lets you select a distance up to 200 km, this will involve downloading lots of data, and the app developer is paying for this (not to mention your own data download time and costs).

The 6 buttons in the lower part access various data and function screens.


The first button shows you the elevation profile in the direction you’re facing, for the specified distance. Green vertical lines marked the locations of highest and lowest elevation in the profile.Your current position is plotted in a Google Maps view in the lower half. Move the slider to the right …


… and the map scrolls to the corresponding position. Markers are plotted every 1 km.


The second button brings up a 360-degree graphic representation of slopes in every direction; the display rotates with your heading. Reddish colors are up-slope, while greens are down, and the intensity reflects the steepness of the slope.


The third button brings up this odd display, sort of similar to the previous one in intent. Here, it’s displaying the “difficulty of travel” in every direction; the fastest way to travel is to move in the direction with the minimal amount of yellow overlay (here, W is the easiest path, with SE a close second).


Fourth button brings up an augmented reality view, with an airplane-like HUD overlaying a camera view (which you can’t see due to the limitations of screenshots). Heading, roll and pitch are displayed. IMO, the least successful and useful screen.


Fifth button brings up a Google Maps view, with your current location plotted as the starting point. Scroll the map in any direction …


… and see a line of points plotted from your original location to a new one. Press the middle button at the bottom (the square with the zig-zag in it) …


… and see the elevation profile over that plotted line of points.


If you scroll the map to another point, and press the “select” button at the bottom, the center of the map will be designated as the start of a new elevation profile, and marked in red; just scroll the map again to set the end point. This way, you can find elevation profiles anywhere, not just from your current location. Pressing the “GPS” button will bring up back to your current location.


Final button brings up a panel to turn the GPS on/off (toggle the top button), and set the distance units to miles or km (toggle the bottom button).

Other issues: Lot of mixed comments on the Android Market on this app; some people complain about its interface, while others couldn’t get it to work. I didn’t have any issues with the interface, and it worked fine on my Droid X running Froyo.

Final thoughts: I reviewed an app called Elevation and Sea Depth a while back that offered similar functionality. While AltitudeProfiler doesn’t do sea depths, it offers a better display and more options for terrestrial elevation profiles. Unless you absolutely need the sea depth data, I’d recommend AltitudeProfiler as the superior app.

GeoCam – Additional Features

Yesterday’s review of the Android app GeoCam  concentrated on its main features, measuring/recording position and orientation info. But it has a few cool additional features as well.


In the lower right hand corner of the main display are flag and map icons. Tap on the flag …


… and enter a name for that location; the position is now stored under that name.


Go to the Geo tab of the Settings section, and tap on the multi-flag icon to get options for your saved “flags”.


“View on Maps” displays the flag markers in a Google Maps view; you also get this by tapping on the Map icon on the main screen.


Tap on a flag to get its name.


The “View List” option lets you see all your saved flags; a long press on any item in the list brings up the option to delete them. The single flag listing in settings has the same function as the Flag icon on the main screen, to give you the option to record your current position.


Where it gets really cool is that if you point your phone in the general direction of a flag, you’ll see its name and distance on the augmented reality (AR) display (note: you’d normally see the camera view as well, but screenshots can’t capture camera views, so you just see a gray background above).


Under the “Geo” tab in settings, there’s also a compass icon; tap on that, and get options to measure distance and height. Unlike apps such as Smart Measure, which require that the object you’re measuring be on a plain, level surface at the same elevation as you, GeoCam uses GPS position data to get distance and height by triangulation. For distance, select the option, center the object in your display, and tap the display center. Then shift over sideways as long a distance as you can, center the object again, and tap the center. GeoCam uses the two GPS positions, and the two orientations of the phone when pointing at the object, to estimate the distance from the midpoint of the measurements to the object by triangulation.

The accuracy will depend strongly on how precisely you center the object, how far apart the two measurements are made, how far away the object is, and what your current GPS error is; the app won’t let you make this measurement if GPS error is larger than 10m. At short distances on level surfaces, Smart Measure is much more accurate, but its accuracy decreases rapidly as the object gets further away, and doesn’t work well at all on uneven surfaces. I tried multiple distance measurements with GeoCam, and with care you can get accuracy to within 5% or less of the actual value for objects about 50 meters or further away.

Once you have a distance to an object, you can use GeoCam’s Height function to roughly measure how tall it is from base to top. Select the Height option and enter the distance to the object in meters. You’ll then be prompted to point first to the base of the object and tap the screen, then the top of the object and tap; from the distance and angle info, GeoCam will calculate height. Didn’t try this too many times, and didn’t have good height info for my test objects in any case, but the values were at least within the ballpark of what I would have expected.

The author keeps adding new features, so it will be tough to keep this review up to date. One promised new feature will be the ability to export the flag positions as a KML file for use in Google Earth. But I’d love to see an import option for KML or GPX waypoints, so that you can load them in for use in the augmented reality mode. The ability to add a flag marker with a long press on the Google Maps view could also be useful.

In any case, given the current price (free), this is a must-have app, and the paid version is definitely worth a look as well.

Orientation-Stamped Imagery And More With GeoCam

Application Name: GeoCam (originally Theodolite)

Description: Augmented reality app that shows compass direction, GPS coordinates, orientation on camera view, plus much more.

Publisher’s website: None

Cost: Free ad-supported version; paid version removes ads, adds video recording and KML export.

Version/date reviewed: v.1.63  /  2-22-11

Phone/OS: Droid X / Android 2.2

Android Market (mobile app only)
Android Market (browser)

Multi-purpose apps can be a mixed blessing; it’s nice to have multiple functions in a single app, but sometimes each individual function is inferior to that in another app dedicated solely to that function. Ulysse Gizmo has been the biggest exception to that issue I’ve reviewed so far, in that all that functions are well-executed. I’d now include GeoCam – it has a lot of functions, some rarely found on other apps, and performs most of them well.


The primary function of GeoCam is to show you the compass direction you’re pointing, GPS coordinates, and phone orientation/tilt, superimposed as an augmented reality (AR) view on the camera display. You can then take a photograph of that view with the additional data superimposed, to have it for your records. When I saw this in an earlier beta version, the one thing I had hoped for was the option to take a picture without all the superimposed data …


… and the app’s author apparently read my mind, because this feature showed up in a later release.


Here’s the view on the camera screen, minus the actual camera input (which doesn’t show up on screen captures). The red square is a guide to getting the phone aligned correctly; when the phone has zero tilt angles, that red box will turn green and align with the green box in the center of the display.

In addition to the information/data displays, there are buttons/sliders to access various controls. The blue magnifying glass at upper left …


… brings up a data screen with position and orientation data. The icon immediately to its right turns on/off adding the AR data to any photos you take The red slash on the icon signifies that no AR data is added to the photo, and tapping on that icon will remove the red slash and put it into the mode that includes orientation data as an overlay on the photo.’

The camera icon at the upper right takes a photo, but you can also use your phone’s hardware camera button as well. Red icon in the lower-left exits the program, though the Back button seems to work as well. The blue “i” brings up a reasonably-comprehensive in-app help screen. The flag/map buttons at lower right? I’ll save those for tomorrow.

The yellow-highlighted arrow at the right brings up a settings/menu screen if you tap on it; you can also bring this screen up by pressing the phone’s Menu button.


There are three settings tabs, Cam (for camera settings), Geo (tomorrow) and Set (which lets you modify the color and font used in the AR orientation overlays). Above is Cam, with the Brightness subsetting selected. You can adjust the photo’s exposure by sliding the numbers at left to highlight the desired over/underexposure with the red line. For my Droid X phone, the view in the camera display always seems to be brighter than the final photo taken, so if I adjust the exposure to be lower, the resulting photos are too dark; YMMV with your phone.


The next camera subsetting lets you modify the picture tints for monochrome, sepia, negative, solarize, and various tints. At least for me, this doesn’t really offer any useful functionality.


The final camera subsetting supposedly lets you select the photo resolution from all the phone’s supported pixel sizes, but on my Droid X, you only get one choice; the author says he’s working on figuring that one out.


In the Set section, you can choose the color of the orientation overlay for best results. Bright sets it to pure white for darker background images, Light (seen above) sets it darker for light images, and Cockpit (seen in the first pictures above) sets it to green. I’ve found that Cockpit is the best all-around choice, as it’s clearly visible under most circumstances.

Other issues: Compass direction is magnetic; I would really hope that the option to set that to true direction is added soon. For now, you have to manually correct for the magnetic declination. And I hope support for all camera photo resolutions will be fixed eventually.

Final thoughts (Part I): If this were all GeoCam did, it would be a must-have app. But it adds some additional AR geographic functionality, plus some measurement capabilities, which I’ll cover tomorrow in Part Two.

Distances, Times and Bearings To Locations

Application Name: Distant

Description: Distances, bearings to locations on a list; travel times to those locations if you’re in motion

Publisher’s website: dixiak

Cost: Free

Version/date reviewed:v.1.0  /  2-21-11

Phone/OS: Droid X / Android 2.2


Android Market (mobile app only)
Android Market (browser)

Create a list of locations, either by manual entry or by tapping on a map, and Distant will give you distance/bearing info to those locations.


In the startup view, you get a preloaded list of exotic destinations; after a GPS or cellular fix is obtained, you’ll see them listed by distance from you (closest first), with approximate direction as well. If there’s a number with an up-arrow following it, that indicates the increase in elevation from your current location to the destination; lower destinations have no such elevation change number, for some reason. Your current GPS position and altitude will be displayed at top, although why it’s in kilometers and not meters I have no idea.


A brief tap on any item in the list (like Thikse Monastery) will bring up a more accurate bearing degree number. A longer tap will bring up the option to view the destination in Google Maps, edit/delete it, or add a new waypoint to the list. New waypoints can be added by manually entering a name, and latitude/longitude location.


From the program menu, you also have the option of adding a waypoint to the list using Google Maps. Scroll to your desired location, and do a long press on the map; the “new waypoint here” popup appears. Tap on it …


… and get the dialog box for adding a name (the coordinates will be enter automatically). Tap on the “disk” icon to save it to the waypoint list …


… and also see it marked on the map.


If you’re in motion, the app will show your current speed and bearing; for a selected waypoint in the list, it will tell you what angle you need to turn to be heading towards it, and how long it would take you at your current pace to reach that spot (89 days to 7 months for Thikse Monaster – long walk). From the list, the destination you’re closest to heading to will be listed in green, and the one you’re moving the most away from will be listed in red.

Other issues: App worked fine. A compass view, with a marker showing which direction you should move to go to the selected location, would be a useful addition.

Final thoughts: Fun as a geography learning tool, for getting distances/bearings to far-way locales. But could also be useful for local waypoints as well, although the navigation tools are a bit limited for that use.

How The FCC Plans To Destroy GPS – A Simple Explanation

Cross-posted at the Free Geography Tools site.

If anyone had told me three months ago that a company was going to propose a system that would fully disable GPS in areas that cover most of the population of the US, I would have ignored them. If someone told me two months ago that the FCC would give this proposal serious consideration, I would have laughed. If someone had told me a month ago that the US Federal Communications Commission  would actually approve this scheme, I would have considered them crazy. And yet, that’s exactly what’s happened; the FCC has given conditional approval to LightSquared’s 4G LTE proposa l (PDF link). If implemented as planned, all current GPS receivers will no longer operate correctly in areas covered by their system, which include the overwhelming majority of the US population. I wish I were kidding, but I’m not. There’s a lot of technical jargon used in discussing this issue, so in this post I thought I’d try to explain the issues with a somewhat less technical, and hopefully more accessible approach. Technical nitpickers may see some oversimplification, for which I apologize … not at all.

At their most basic level, GPS receivers are pretty close to FM radios.  So to explain some of these principal issues behind the GPS problem in understandable terms, I’ll use the basics of FM radio broadcasting. To tune in an FM radio station, you turn your radio’s dial or push the buttons until the receiving frequency of the radio is set to that of the station: 89.5, 101.7, 104.1, and so on. Those numbers refer to the number of cycles per second of the frequency in millions, so that 101.7 is a radio signal operating at 101.7 million cycles per second, abbreviated as 101.7 MegaHertz (MHz) for short. But that’s just the main frequency, sometimes referred to as the central “carrier wave”; receiving a signal at just at frequency wouldn’t give you any signal information, like music/talk/news. To encode that signal, the frequency of that carrier wave is varied, or “modulated”, by the signal; your radio then monitors those variations in frequency around the central carrier wave’s frequency, and then converts them back to the original signal, music/talk/news. Frequency being modulated = Frequency Modulation = FM.

If you had two stations broadcasting in the same area on the same frequency, they would interfere with each other, making both of them unlistenable. If the frequency is only slightly different, they will also interfere with each other. To prevent this, the FCC licenses broadcasters to transmit on a specific frequency, and also makes sure that the frequencies are far enough apart so that one station’s broadcasts won’t interfere with another station. In the original days of FM, the minimum spacing for FM frequencies was 800 thousand cycles per second (800 KiloHertz or KHz, 0.8 MHz); so if one station was at 90.1 MHz, the closest frequencies allowable to that station would be 89.3 MHz and 90.9 MHz, offset 0.8 MHz up and down from the center one.

With time, the FCC has loosened that frequency spacing requirement up a bit,  taking into account factors like improved FM radio technology, the broadcast power of the station, and the distance from other stations assigned the same frequency. For the most part, the system works, but  you’ve probably experienced occasions when you’ve been listening to one FM station, only to have a second signal cut in and interfere with the first station’s signal. This is especially noticeable if you drive right by an FM radio broadcast antenna; the signal from that station can be so strong, it wipes out reception from any stations that are even marginally close to it in frequency. Because a station requires about 150 KHz of frequency modulation bandwidth to carry its signal, the FCC has also mandated that all standard FM tuning signals need to be at least 200 KHz apart; that’s why your FM tuner jumps from 100.1 to 100.3 to 100.5, bypassing 100.2, 100.4; those frequencies need to be kept free to make sure stations don’t “step” on each other’s signals.

OK, so back to GPS. While GPS doesn’t technically use frequency modulation, it uses a closely-related system called “phase modulation“, which also relies on a carrier wave. The main signal broadcast by GPS satellites, and used by the overwhelming majority of GPS receivers for determing position, is the “L1” frequency, with the carrier wave 1.57542 billion cycles per second (aka a GigaHertz, or GHz); including the total frequency band required for phase modulation, the range is 1.559 GHz  to 1.610 GHz. Phase modulation is used to transmit digital information with pulses 1-millionth of a second wide from the satellites to your GPS receiver; the receiver takes this data from multiple satellites, and uses it to calculate your position. This frequency was defined in the late 1970s, and has been used continuously for GPS operations since the system went operation early in the 1990s, twenty years now. This frequency band is also part of a larger range of frequencies designated for use in satellite broadcasting. As with FM radio, you need to separate the frequency bands far enough apart so that the signals don’t interfere with each other; you also need to make sure that a signal at one frequency isn’t broadcast at such a high power that it will interfere with signals broadcast at neighboring frequencies. The latter isn’t usually a problem – the signal strength from satellites 12,000 or 23,000 miles above the earth is usually so low that interference between adjacent frequency bands is infrequent.

So, enter LightSquared. LightSquared wants to build a high-speed wireless broadband network on the cheap. Problem is, the FCC holds regular auctions for frequency space, with all the big wireless players (Verizon, ATT, Cingular, Google) bidding billions of dollars for this frequency space to carry their traffic; a smaller company like LightSquared can’t compete financially. But LightSquared came up with several clever workarounds to get past this issue. Satellite frequencies are also regulated and auctioned by the FCC, but they usually go for prices far lower than terrestrial frequency space. LightSquared acquired a small satellite company called SkyTerra that already owned frequency rights for 1.525 GHz to 1.559 GHz, directly adjacent to the frequency band designated for GPS. They then announced plans to develop a satellite-based Internet access service using those frequencies. Satellite signals by themselves would be so weak, that Internet speeds would likely be limited to no more than a few megabits per second, comparable to current 3G wireless network speeds. But FCC regulations have a loophole that allows satellite services to broadcast stronger signals terrestrially to supplement satellite coverage in those areas where coverage might be weak. This terrestrial broadcast signal can be as strong as the FCC allows, and is covered by the satellite auction price paid by the licensee.

So LightSquared announces a “satellite Internet access” service, but one supplemented by free use of terrestrial transmitters. But these terrestrial transmitters aren’t intended merely to fill in gaps in satellite coverage; these are high-power transmitters that allow LightSquared to offer the equivalent of 4G wireless Internet speeds (up to 100 Mbps), without paying for terrestrial spectrum. So that’s how LightSquared plans to do high-speed wireless broadband on the cheap – they don’t have to pay for the frequency spectrum they’re using. It’s a clever use of loopholes, and one I wouldn’t have a problem with, except that they will be broadcasting at high-power at a frequency that will interfere with GPS signals to the point that GPS receivers will no longer operate correctly. And this isn’t just a few transmitters – LightSquared’s plans are to install 40,000 transmitters to cover areas that contain most of the US population.

This GPS interference isn’t just a hypothesis. Members of the US GPS Industry Council, Trimble and Garmin met with the FCC on January 19th to present and discuss Garmin’s tests of the LightSquared proposal (PDF link), and its potential for interference with GPS receivers. Garmin used LightSquared’s own proposed transmitter power levels to evaluate the effects of this transmitters on an automotive GPS (Garmin nuvi 265W) and an avionic GPS (GNS430W). Here are screen captures summarizing the effects of the LightSquared transmitters on GPS receiver performance at different distances:



If you get within 0.66 miles of a LightSquared transmitter in open conditions, you’ll lose your position fix with the automotive nuvi 265W, further away in a city environment like New York or Chicago. The results are even worse for the aviation GPS. The FAA has essentially discontinued support for the old LORAN electronic navigation system in favor of GPS, and now LightSquared has proposed a system that essentially disables GPS in exactly the areas aviation needs it most. Garmin’s conclusion, shared by other industry proponents:

The operation of so many high powered transmitters so close in frequency to the GPS operating frequency (1575.42 MHz) will create a disastrous interference problem to GPS receivers to the point where GPS receivers will cease to operate (complete loss of fix) when in the vicinity of these transmitters.

Other government agencies are also concerned. In a January 12th letter to the FCC, Lawrence Strickland, the head of the National Telecommunications and Information Administration (a branch of the Department of Commerce) wrote:

Grant of the LightSquared waiver would create a new interference environment and it is incumbent on the FCC to deal with the resulting interference issues before any interference occurs. Several federal agencies with vital concerns about this spectrum band, including the Departments of Defense, Transportation and Homeland Security, have informed NTIA that they believe the FCC should defer action on the LightSquared waiver until these interference concerns are satisfactorily addressed.

And yet, on January 26th, waiving many of their standard procedures, the FCC gave conditional approval to LightSquared’s proposal (PDF link). The only bone thrown to the GPS community was the requirement that LightSquared work with the GPS community to resolve these interference issues. But since LightSquared is funding the study, there are concerns about how unbiased the results will be. Unless you can change the laws of physics, and principles of electrical engineering, you can’t resolve this problem directly with existing GPS equipment as-is. LightSpeed acknowledged as much when they stated that they saw the main purpose of this joint effort as seeing how to modify GPS equipment to implement “filtering so that they don’t look into our band”. There are only two ways to implement this:

  • Retrofit current GPS equipment with improved electronics; possible but expensive for high-end equipment, impossible at a reasonable cost for consumer-grade equipment
  • Replace all current incompatible GPS receivers with new ones that have improved filtering. While the marginal cost increase on a GPS receiver is likely to be low, the requirement that you have to replace the entire unit will make this staggeringly expensive. Every GPS receiver (automotive, aviation, handheld, mobile phone) would need to be replaced.

There’s additional fodder for conspiracy theorists as well. LightSquared filed its proposal on November 18, 2010, right before Thanksgiving. The FCC fast-tracked its proposal, and limited the comment period to December 2-9, 2010, over the objections of the GPS industry and other opponents. In approving LightSquared’s proposal, they acknowledge waiving some of their requirements (PDF link). And for the real conspiracy fans, the principals behind LightSquared may have political connections deep inside the current adminstration (PDF link). In normal circumstances, I would dismiss all this as nonsense, but the FCC’s decision is blatantly crazy, I have to wonder.

If it weren’t for its detrimental consequences on GPS, I’d think that LightSquared’s system would be a great idea – high-speed wireless Internet access in most populated places, and lower-speed access anywhere in the world by satellite. And if the FCC wants to propose regulations requiring better frequency band filtering in GPS receivers, and other types of satellite-band-based systems, to allow exactly these kind of systems to be developed in the future, I could get on board with that as well. But it should be up to LightSquared to prove that their system won’t interfere with GPS the way it is right now. GPS is the established system – twenty years of operation, hundreds of millions of receivers, uncountable numbers of applications. If LightSquared interferes with GPS, it should be required either to fix the problem itself, or be denied permission to function. That the FCC would even consider LightSquared’s proposal without modification, much less approve it, is astonishing.

If you’re interested in letting the government know how you feel, GPS World has a page on how to contact the relevant members of the House and Senate. GPS World is also the go-to source for coverage of this issue:

Addendum: A great article at InsideGNSS.

And a HT to GPS Tracklog Waypoints for the original link to GPS World.