We’re big fans of Google Earth here at DestinSharks.com and it is unsurpassed for arm-chair global exploration, but what about its use as a real-time mobile mapping solution? To use Google Earth in a mobile setting you need 4 things – a portable PC, Google Earth (preferably cached with imagery from the area of interest), a GPS which supports NMEA serial or USB output, and software which translates the GPS output into KML for Google Earth (or the latest release of Google Earth 4 Plus, Pro, or Enterprise). Read on as we review 4 ways turn Google Earth into a powerful moving map and find out which application might be best for you – at the end of the review we have a video showing each in action. If you’re looking for a good PC GPS, read our companion Garmin 18 review.
Moving-Map Options for Google Earth
1 Google Earth Plus
Google Earth Plus is a $20 upgrade over the standard free client. One of the additional features is a GPS menu tool which allows for realtime tracking via Serial or USB GPS and the download of waypoint, track, and route data from compatible GPS receivers. You can read more about supported features and GPS units in the Google Earth Plus documentation. This option is the only one with direct support for USB only GPS units from Garmin.
Using the realtime tracking feature is simple – plug in your GPS, open the Realtime menu in Tools-Options-GPS, select the GPS message type (NMEA for serial, Garmin PVT for Garmin USB), and press the ‘start button’ shown in the screen shot at right (click for a large view). Google Earth will do the rest. Unfortunately, the rest is somewhat limited compared to the other software in this review. You can set the track length and update period and not much else. Google’s automatic zoom and follow feature seemed to overzoom in our trials. Frank at gearthblog.com also reviewed GE’s realtime GPS tracker recently.
2 GEtrax is a low-cost payware solution ($10) to realtime GPS tracking in Google Earth (along with a good set of other functions). The program is available with a 30 day free trial. The trial version appeared to be fully functional in our testing – although we did not test all the features. It supports the NMEA GPS message protocol via Serial Port, but requires ‘virtualizing software’ such as GPSGate for use with a Garmin USB-only Protocol GPS. GEtrax can also display prerecorded tracks in many GPS log formats and realtime data from the APRS Ham system via the internet.
As you can see in the screen shot, you can select the eye altitude and tilt, add additional placemarks for the start, finish, and fastest point of a track, set track transparency and colors, and select a north up or heading up following mode. GEtrax offers 4 options for track altitude. You can clamp the track to ground, use the GPS altitude values, extrude the track up to your GPS altitude, or set the altitude relative to velocity complete with an adjustable scale factor. One issue we discovered in our area with the speed as altitude feature was that ‘zero’ altitude appeared above the ground in Google Earth in our area.
Earth Bridge is a freeware program built with a focus on realtime tracking in Google Earth and GPS data logging. The user interface is split into 3 main tabs.
The 1st tab is ‘KML Output Settings’. Earth Bridge offers nice customization of the main GPS position icon label and speed units. You have the option to use altitude data (such as when flying) or leave the track clamped to ground. You can specify the desired viewing altitude and angle while following a moving track. Earth Bridge will also display the cumulative track with a nice set of options to control the length of track log, extruded and ‘shadow’ options for 3D tracks, and the ability to save out track data to a KML file.
The 2nd tab shows GPS status information. This is far and away the best GPS diagnostic feature in any of these programs. From this tab, you can see the raw NMEA serial data, which satellites are in view and their signal strengths/positions, and the core position/accuracy data. You can freeze the NMEA stream display at any point and save out the raw message log for external analysis.
Finally, the Preferences tab is used to set default paths for saving KML and GPS data, configuring the serial GPS connection, and general program options. The last Earth Bridge release was nearly a year ago – hopefully we’ll see continue to see updates for this promising program.
Our last application in this review is GooPs. Unlike GEtrax and Earth Bridge, it does not require installation – the program is entirely self contained in a single file. GooPs is free and is being actively developed (and some features are not fully functional), but it does extremely well with those which are. Besides serial GPS input, GooPs can also receive GPS NMEA messages over TCP/IP networks and can display more than 1 track at the same time. We did not test this multi-track ability except via the built-in demo mode.
Similar to the other programs, you have the option of a 2D or 3D track, extrusion option for the 3D track, choice of track color and units. An added option is called ‘SpeedTrack’. When speed track is selected, the track and position icon color are based on velocity. This provides an intuitive way to review speed along a track line.
Once a connection is made to a live GPS, GooPs really begins to shine. From the main GooPs control, you select which source (if more than 1) to actively follow and the auto follow mode. GooPs has the best automatic view control in this review. If full auto mode, it sets tilt, zoom, and heading and adapts them based on the current velocity. As velocity increases, the view zooms out and up (towards looking straight down) – when stopped, the view zooms in close and tilt low to maximize the view ahead. The auto modes can work independently – so if you don’t like the zoom level, you can control this manually without loosing auto tilt.
Also from the main control you can pause display updates and save out the current track to KML. GooPs has very smooth updating and fast response. Our screen video doesn’t really do it justice – as our laptop was struggling with maintaining the fast update rate in Google Earth while also capturing full-screen video. We encourage you to download GooPs and try it yourself in demo mode.
We put together a video which shows each program in action with an EarthNC marine chart as the backdrop. If you’ve used these or other GPS solutions with Google Earth, please share your experience by commenting below.