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Archive for the 'GPS' Category

Map Lightning Strikes With ThunderHunter

Application Name: ThunderHunter

Description: Uses the lightning flash and succeeding thunderclap to map the location of lightning strikes in real time

Publisher’s website: ThunderHunter

Cost: Free

Version/date reviewed: v.1.2  /  8-10-11

Phone/OS: Droid X / Android 2.3


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

It’s “monsoon” season here in Arizona, which means that more days than not, there’s a good chance of thunderstorms. ThunderHunter uses the delay in seeing the lightning flash and hearing the thunder to calculate approximately how far away a lightning strike is. If  you point the phone in the direction of the lightning strike, it uses the phone’s built-in compass and GPS to plot the approximate position of the strike.


Starting up the app gives you the screen above; the compass in the upper right is live, and shows you the approximate compass direction your phone is pointed. When you see a lightning flash, quickly swivel the phone to point in  the direction you saw the lightning hit, and tap the button with the “eye/lightning” icon …


Now wait for the thunderclap; when you hear it, tap the button with the “ear/lightning” icon …


Since light travels almost instantaneously, but sound travels much slower (about 300 meters / second), ThunderHunter uses the difference in time between the flash and the thunder to calculate the distance. The arrow icon at lower left returns you back to the first screen, to wait for another lightning flash. The button at lower right takes you to a Google Maps view …


… where it uses the calculated distance and the orientation of the phone to plot the location of the lightning strike (cloud/lightning icon);  your current position is plotted as the “green man” icon. The GPS will fire up to get your current position,  then turn off to minimize power use. Use the “arrow” button to go back to the previous screen.

Other issues: Don’t worry about not having the phone pointed in the right direction when the lightning hits. ThunderHunter uses the direction you’re facing when you tap the “ear” icon after hearing the thunder, so as long as you point the phone in the direction you saw the lightning before you hear the thunder, the direction and position will be plotted correctly.

Final thoughts: Clean, simple, fun, does what it’s supposed to. Most comparable apps only calculate distance, ThunderHunter goes the extra step and plots the position. Recommended. I will say that if you can see lightning and hear thunder, you should find a safe place to sit out the storm. Lightning can strike without warning as far as 10 miles away from the storm’s central location.

Live Calibration Of Map Images With MapCalibrator

Application Name: MapCalibrator

Description: Geocalibrates a map image using GPS positions, then plots your current position.

Publisher’s website: None

Cost: Free

Version/date reviewed: v.1.06  /  7-20-11

Phone/OS: Droid X / Android 2.3


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

There are lots of apps (e.g. Locus, OruxMaps) that let you take previously-calibrated map images and then view your location on them using your phone’s GPS. MapCalibrator is a bit different – you can take a map image, either download from external sources on your phone, or photographed using the camera, and then calibrate it using three live GPS positions. After calibration, you can then view your approximate position on the map.


The program starts by asking you to select a map image for calibration. This can be a map picture you’ve uploaded to your camera, as with the topo map images above, or a photo you take with your phone’s camera. For example, you could take a photo of a trail from an info kiosk at the trailhead, then use the program to calibrate this map image.

I tried using map images in TIFF, GIF, PNG and JPG format. The TIFF format didn’t load at all into the program; the GIF and PNG formats loaded successfully, but I was unable to calibrate either of them. Only the JPG image worked correctly for me.


When you reach a known point in “real space” for which there’s a corresponding point on the map, you can add a calibration point. Press the Menu button, then select “New Reference Point”. A blue circle will appear in the map display, and you tap-and-drag that blue circle so that the center dot is on your current position. This can be a bit tricky, as your finger will cover the blue circle as you drag it, making it difficult to place accurately. The GPS is also not on continuously, so you’ll need to stand in one spot for about 15 seconds or so before calibrating, to make sure the program has your current position accurately.


Once you have the calibraiion point set, press Menu = Use Reference Point to save that calibration point. Your GPS coordinates are entered automatically, but if you have more accurate coordinates from a map or another GPS, you can enter them manually in degrees:decimal minutes format.


You’ll need to enter three calibration points in order to complete the calibration process. You can add additional points, but they won’t be used (though the program’s author indicates he might add the ability to use additional points in the future).


Once calibrated, your current GPS position is plotted as a red circle/dot on the map image. The GPS updates about every 15 seconds or so, so the position won’t always be up-to-date. In my tests, the calibration was pretty good, although the GPS position would sometimes jump to an offset position, then jump back again to an accurate position.

Other issues: The program doesn’t let you save image calibrations for future use, which is a big drawback; that means you’ll have to calibrate an image every time you want to use it. You should also remember that some maps are “schematic” in nature, i.e. scale, distance and direction may not be depicted with complete accuracy; such maps will be virtually impossible to calibrate accurately. You should try to use three calibration points that are spaced reasonably widely for the best results; if the points are too close together, the calibration is likely to be less accurate.

Final thoughts:  In most cases, you’d usually be better off using apps like Locus or OruxMaps that allow you to use both online maps sources and your own calibrated maps. However, for those instances where the only map available is one posted on a bulletin board or info kiosk, MapCalibrator is a useful tool to have.

Map Lightning Strikes With Thunderhunter

Application Name: ThunderHunter

Description: Map the approximate position of live lightning strikes.

Publisher’s website: ThunderHunter

Cost: Free

Version/date reviewed: v.1.2  /  7-17-11

Phone/OS: Droid X / Android 2.3


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

It’s monsoon season again in Arizona, which means thunderstorms more days than not. You probably know the standard method for estimating how far away a lightning strike is: start counting seconds as soon as you see the lightning flash, stop when you hear the thunder, then divide the number of seconds by 5 to find out how far away the lightning strike was in miles. ThunderHunter automates that process, and adds a twist: if you point your phone in the direction of the lightning flash, it will plot the approximate location of the strike in Google Maps.


Starting up the app brings you this display. The compass at upper left shows the magnetic direction your phone is pointing in, the “?”  at upper right brings up very minimal help. When you see lightning flash, turn your phone quickly to face in the direction of the lightning, and tap the “eye/lightning” button.


The button will change to an “ear” icon; when you hear the thunder from the lightning flash, press the button.


You’ll get an estimate of the distance from the lightning strike in km and miles. Tap on the yellow arrow at lower left to go back to the lightning recording screen; tap on the map …


… and the app will fire up the GPS to get your current position, then plot the approximate position of the lightning strike, along with your current position (the little green man).

Other issues: Most times, the app will determine direction based on which way the phone is pointing when you hear the thunder. So you can hit the “eye” button when you see a flash in any direction, have time to point the phone at the direction of the flash, then press the “ear” button when you hear the thunder to get an accurate time and direction. On a few occasions, thought, that didn’t seem to work correctly, and it took the direction the phone was facing when the “eye” button was pressed.

Final thoughts: Nifty little app that gives you an approximate distance and location for lightning strikes. Best used indoors at a window, though, since if you can hear thunder and see lightning, you really shouldn’t be outside.

Maverick: A Basic GPS Map Application

Application Name: Maverick

Description: Basic GPS mapp app

Publisher’s website: Code Section

Cost: Free lite version limited to 5 waypoints and one track;$5.95 Pro version removes those limitations.

Version/date reviewed: v.1.6.1  /  7-5-11

Phone/OS: Droid X / Android 2.3


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

It’s nice to have GPS map apps with lots of features and capabilities, but these massive feature sets can sometimes make these apps harder to learn and use. Maverick has a somewhat more limited feature set compared to other GPS map apps, but its streamlined feature set makes it very fast, and easy to use.


Default view when you start up is your current position, displayed in a Google Maps interface. Other map options include Google Satellite/Hybrid/Terrain, Bing Maps/Satellite/Hybrid, Wikimapia and Nokia/Ovi maps, accessible with the “Maps” button at upper left; you can also convert your own maps into a compatible format with the paid mapc2mapc utility. Online maps are cached for viewing when you’re out of network range. The zoom buttons (and zoom level) are conveniently located at the upper right, and are an improvement over the default zoom buttons for Google Maps.

The blue triangle represents the field of view ahead of you, as determined by the compass on your GPS. Unfortunately, this uses magnetic direction instead of true direction, so it can be a bit off (11 degrees for my location); I wish app writers would always use Google’s built-in function for correcting for magnetic declination.

If you scroll the map by dragging, a blue arrow will show up at left (visible above); tapping on that will bring you back to your current GPS location. This is a nice implementation of this feature.

Tapping on the icons below brings up a number of additional screen options.


The Binoculars icon brings up a search screen.


The green flag icon puts a waypoint at the center of the screen; it also changes into a pencil icon, which you tap to bring up the waypoint editing screen above. Waypoints are saved in KML format, and can be exported for use in Google Earth and other apps.

The “yellow” checkered icon turns GPS on and off, while the icon at lower right turn GPS track recording on and off; you can also turn on track management using the Menu button. The button at lower left toggles between Map mode (the default) and access to three alternate data screens:



Compass view shows the direction your phone is pointing in; if you have a waypoint set as a destination (as above), it also shows you the direction to travel in to reach that waypoint, and the distance to that waypoint.


The time/track data screen lets you start recording a track, and the total time/distance/average speed along that track. If you have an account at, you can upload the track there.


The final screen is a GPS info screen. Tapping on any of the data screens lets you choose between twenty different datasets for that screen (e.g. UTM coordinates, sunset, ETT, etc.), offering more flexibility in data display than other similar apps.

Final thoughts: Nice, clean, fast, simple GPS mapping app. The free version is definitely worth a look. However, I think the paid version is a bit overpriced at $5.95; apps like Locus and OruxMaps offer larger feature sets at a similar or lower price.

Location Coordinates (Plus Reverse Geocoding?) With GeoPicker

Application Name: GeoPicker

Description: Gives you latitude/longitude coordinates for a selected point, plus supposedly reverse geocoding (address from coordinates/position).

Publisher’s website: Android Life

Cost: Free

Version/date reviewed: v.1.2  /  6-25-11

Phone/OS: Droid X / Android 2.3


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

GeoPicker is a simple, easy-to-use geographic utility for determine latitude/longitude coordinates for a location. It also may have a killer feature for most of you: reverse geocoding for a point (address from coordinate position). But more on this in a bit …


App fires up the GPS automatically, but defaults to a position in the middle of the US.


Select “My Location” from the menu to go to your current GPS location. Tapping on the coordinate display toggles between degrees-minutes-seconds (boo) and decimal degrees (yay). As in standard Google Maps, pinch to zoom, or tap on the map and use the +/- zoom controls; touch and drag to scroll.


As you scroll, a red “X” appears under the final pin location. Stop scrolling and …


… the pin drops into location.


From the app Menu, you can copy the current coordinates into your phone’s clipboard, for pasting into another app. Other options include getting driving directions from your current position to the selected point, toggling between Google Maps/Satellite views, and searching for landmarks and addresses.

The app also has an option for telling you what the nearest address to the current pin location is (reverse geocoding), but unfortunately this caused my Droid X to force-close the app every time. From the App Market comments, this appears to be a common problem with Motorola Droid phones; other phones may not have this issue. You can do something similar in Google Maps, albeit with less precision – a long press on a location in Google Maps will bring up the closest address to the selected location as a pop-up balloon. Tapping on that popup balloon will take you to a page with additional options like directions, Street View, and local search. However, there’s no crosshair for positioning in Google Maps, so you have to zoom in very close to be able to place your finger in the right spot.

Final thoughts: Handy utility for picking up arbitrary position coordinates, especially if you need to copy/paste them into another app. If the reverse geocoding works for you, that’s an added bonus.

Measure Distances, Get Elevation Profiles With Survey

Application Name: Survey

Description: Distance and elevation profile tool

Publisher’s website: sys-irap

Cost: Free (ad-supported)

Version/date reviewed: v.0.7.3  /  6-23-11

Phone/OS: Droid X / Android 2.3


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

The Survey app is an odd mix of different functions, some of which work well and are useful, others less so.


Start up the app, and get three options: Measure, Short distance, and Long distance.


“Measure” brings up the view from your camera (not visible in the screenshot above), along with a graduated on-screen scale and slider. The idea here is that if you know the distance to an object, you can set it using the slider, and the scale will adjust to measure the true size. Not really sure how useful this is, as it only works out to a distance of 5 meters max, and fairly small sizes. Seems to me it would be easier just to pull out a tape measure.


The “Short distance” option brings up another camera view, and a superimposed ground line (red) and ground mesh. The idea here is that if you’ve entered the camera’s height above the ground in the Settings section, and if you put the ground line at the base of an object at the same ground level as you, you can determine the distance to the object, and use the vertical scale to determine the height. It works, sort of, but only to about a distance of 75-80 meters, and not very accurately at that. The Smart Measure app works in a similar fashion, but is easier to use and is marginally more accurate.



The “Long distance” function is substantially more useful. Select this option, and you’ll get a Google Maps view with your current GPS location plotted as a base location. You can tap and drag this icon to set a different base location; unfortunately, there doesn’t seem to be an easy way to reset it to your current GPS location without backing out of this screen. The icon control at top left toggle between Google Maps/Satellite views (right icon), while the one at right centers the view on the current base location.


A long press on a different location on the map creates a “survey point” at that location, marked with a camera icon. Press the “Survey” button at the bottom …


… and get coordinates/elevations for base location and survey point, and the distance from the base point to the survey point. “G.H.” stands for “ground height”, and is determined by GPS for the base location, and always set to 0 for the survey point. You can adjust the ground height for either location with the button controls to the right.


Tap on the camera icon, and get an augmented reality view through your camera, with the arrow telling you which direction you need to rotate the camera to have it oriented towards the survey point.


When oriented correctly, the survey point will show up as a blue dot, labeled with the distance.


Tap the other icon from the map screen, and get a plot of elevation from the base location to the survey point in orange. It’s not clear from the app what the green and red lines are; I believe they’re elevation plots and direct point-to-point sight lines that include the curvature of the earth’s surface, but I’m not sure.

Other issues: This app really needs better documentation; it’s not entirely clear how some of these functions work. The app description also implies that you can take geotagged camera shots of various screen views, but I couldn’t figure out how to get that to work.

Final thoughts: There’s the kernel of a good app here, and it’s worth taking a look at. But I prefer Smart Measure for distance/height measurements, and AltitudeProfiler for elevation profiles (though the latter has data download limits).

Add GPS Status Data To Any GPS-Enabled App

Application Name: GPS Monitor

Description: Shows basic GPS data in the status bar whenever any app enables GPS

Publisher’s website: Illyrium

Cost: Free basic version; paid Pro version adds additional features

Version/date reviewed: v.1.0.5  /  6-22-11

Phone/OS: Droid X / Android 2.3

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

Many GPS apps for Android come with a GPS status screen that shows the number of GPS satellites currently in the sky, the number of satellites for which a signal has been found, and whether a GPS location fix has been locked in. However, many popular apps like Google Maps/Navigation/Earth have no such indicator; there’s only a GPS status bar indicator that shows you whether you have a fix or not. GPS Monitor adds an additional indicator to the status bar that shows the number of satellites that a signal is being received from, the number of satellites for which there’s a position “fix”, and whether a final position fix has been obtained.


Running the program starts up a resident service on your Android phone; anytime you start up a program that enables your GPS, the service adds an icon to the status bar (above, at left). The number indicates the number of GPS satellites from which a signal is being received, while the “red eye” indicates that no position fix has been obtained.


Once a GPS position lock has been obtained, the “red eye” turns in to the green symbol seen at upper left; the green number indicates the number of satellites for which a signal lock has been obtained.  You can change this number to all satellites in view using the program’s Settings section, but the default setting of satellites with a signal lock is probably the best option.


Pull down the status bar, and you’ll get more information, including the total number of satellites for which a signal is being received (the first number), and the number of “signal lock” satellites (the second number).


The second line in the status bar dropdown is an additional information field that can be specified in the Settings section; however, I couldn’t get this to work on my phone for any of the options (from the app reviews, I gather this is an anomaly). Another available option in Settings is to start/stop the GPS Monitor service, but even after disabling this option, it started up again on its own when I rebooted my phone. It uses about 6-7 MB of RAM, something to keep in mind if you have a low RAM phone or a lot of other services running.

Other issues: The paid Pro version currently only adds an audio tone to indicate when GPS has been enabled, and when a fix has been obtained. The developer indicates that he’ll be adding GPS diagnostics to the app, as well as a “keep alive” option that will keep the GPS running even when no app requires it. The latter is great for quick position fixes, but can really burn through your battery very quickly.

Final thoughts: Unless RAM is tight on your system, installing the free version is a no-brainer; having a satellite status/number icon for apps that don’t come with it is a huge help in figuring out whether your GPS is working correctly or not. For the paid Pro version, I would wait until the additional features are added (and also whether the additional information field is working on your system).

Range Circles In A Google Maps View With CircleMap

Application Name: CircleMap

Description: Draws range circles in a Google Maps view

Publisher’s website: pscdroid

Cost: Free (ad-supported)

Version/date reviewed: v.1.1.4  /  6-14-11

Phone/OS: Droid X / Android 2.2


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

CircleMap draws a set of concentric range circles on top of a Google Maps interface.


The initial view shows a wide-area zoom, with constant distance circles centered on your current location. Use pinch-to-zoom to zoom in and out, or tap on the screen, and +/- zoom controls will appear at the bottom.


As you zoom in, the distance spacing for circles changes to match the zoom; unfortunately, you have no control over the spacing. Your current location starts out in the center, but if you drag the map over, a distance measure (red line with distance in metric units) will show up, indicating the distance between your current location and the center point of the map.


From the menu control, you can set a base location for measurement other than your current location by scrolling to the desired location and choosing “Set base point”. The “Current position” control puts your current GPS location at the center of the screen; if that’s not the current base point, choosing “Set base point” will make it so. Finally, “Change map” toggles between the standard Google Maps view and the satellite/hybrid view. The latter doesn’t work very well, as the range circles are drawn with such thin red lines that they’re difficult to see against some backgrounds.


The pencil control in the lower-right-hand corner of the first three screenshots lets you draw freehand on the map, but the utility of this is marginal; it makes the range circles go away, and you can’t save your drawings. Tap on the double-arrow control to erase the drawing and go back to the range circles view.

Final thoughts: The only app of its kind that I could find on the market, and does a decent basic job. Would be a lot better if you had control over range circle spacing and units, and the thickness/color of the circle lines.

Geographic Data Recording On Android With Memento

Application Name: Memento

Description: Database app with custom form design, GPS geolocation input

Publisher’s website: Memento

Cost: Free ad-supported version; $9.95 Pro version removes ads, removes limits on number of databases that can be synced with Google Docs

Version/date reviewed: v.1.8.3  /  4-24-11

Phone/OS: Droid X / Android 2.2


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

Memento is generally regarded as the best consumer-level database app for Android. You can select from 11 standard data templates (Tasks, CDs, DVDs, Purchases, etc.), browse an online catalog where others have shared their templates, or create your own Custom data template, choosing from 19 different data types:

  • Text
  • Integer
  • Real number
  • Boolean
  • Calculation
  • Date
  • Time
  • Date/Time
  • Contact
  • Image
  • String values
  • Multiselect values
  • Audio
  • Currency
  • Rating
  • Hyperlink
  • Barcode
  • Link to entry
  • Link to file
  • Password
  • Phone
  • Email
  • Google Maps coordinates

Of particular interest here is the last one; you can save geographic coordinate data using a Google Maps interface in conjunction with GPS.


Here, I’ve created a simple database, with a text field and location field.


Tapping the Location field brings up a Google Maps view, and fires up the GPS; your current location will be marked by the blue dot.


Ideally, the default would be for your current location to be the desired location for recording. However, Memento requires you to select a location by tapping on the map view; the selected location is marked with a pushpin icon. Accurate placement requires you to zoom in to the maximum zoom level, and even then it may take you some practice to get it right. You can also zoom out to a different location, and position the pushpin there.


Clicking on OK enters that location in to the appropriate field; clicking on Create saves the record.

Databases can be exported in CSV format, although some data types like images cannot be exported to this format; you can also import data in CSV format to a data template, if you follow the directions to make sure the data fields in the CSV match the data fields in the template correctly.

Even more usefully, you can sync your database automatically to a Google Docs spreadsheet. Syncing is done manually, so that you can record data while offline, then sync it up later with Google Docs. Syncing works both ways, so you can add data in Google Docs, and have it synced to your Android unit. Once in Google Docs, you can analyze the data, manipulate it, and export it in a variety of formats (e.g. CSV, XLS). It’s usually best to do this on a copy of the data, as modifying the original spreadsheet may result in sync problems later on.


One quirk of the geographic coordinate recording is that the latitude and longitude are combined into a single entry, separated by a colon, as seen above in a screen capture from Google Docs. However, it’s pretty easy to convert that into split Latitude/Longitude columns:

1. Make a copy of the synced spreadsheet to avoid sync issues later on.

2. In the copy, create a new C column, and label it Latitude.


3. Use the Split command to split the data in the B column (Location) into two separate data fields. You need to specify the spreadsheet location you want to modify (B2 here), and the delimiter (a colon), so you would enter =Split(B2,”:”) into the C2 column. Hitting the Enter key will now split the B column data into two data entries, the first half going into the C column, the second going into a new D column:



4. You can now copy and paste the C2 data into all the other rows in the C column, and have all that data split as well; the D column is the Longitude, so you can label it as such:


If you export this modified spreadsheet as a CSV or XLS file, some mapping/GIS programs can open it directly. Otherwise, you can use a program like MapWindow to convert the CSV file into a GIS-friendly shapefile format, or a program like DNRGarmin to convert it to a GPS-friendly GPX format.

Other issues: The free version limits the number of databases you can sync with Google Docs, but I couldn’t find out anywhere what that limit was. The in-app help is terrific, maybe the best I’ve seen, and it’s available even when you’re offline.

Final thoughts: The free version is a no-brainer must-have; this is the best basic database app for Android, especially with the geographic capabilities and Google Docs sync. If you need to sync lots of databases to Google Docs, the Pro version is expensive (for an Android app), but may be worth it.

Local Points Of Interest In Wikipedia

Application Name: Wikipedia Places Free

Description: Lists Wikipedia entries near your current location.

Publisher’s website: 2-3

Cost: Free ad supported version; $2 paid version removes ads.

Version/date reviewed: v.1.11  /  4-1-11

Phone/OS: Droid X / Android 2.2

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


Straightforward app – gets you GPS location, and lists any nearby locations geotagged in Wikipedia. Tap on a list item …



… and go to the mobile browser view of that page; your phone’s Back button will take you back to the app.


Clicking on the “map icon” next to a listing brings you to a map view of that location; you can select any supported and installed  app (Google Maps here, but works with Bing, Mapquest, Locus, etc.). It’s accurate, but some kind of more-visible placemark would be useful.

Other issues: Lots of nags to upgrade to the ad-free version, but if you use it enough to be bothered by those, you really should upgrade.

Final thoughts: Other apps show Wikipedia locations as small icons on a map, that can be hard to tap accurately; this list approach definitely has advantages.