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To match the UTC times associated with a GPS tracklog to the local times associated with the photos, the program has to convert UTC time to local time. By default, the program does this by looking at your computer's time zone information and whether daylight savings time is in effect for your location. This process can be problematic in some situations. Optionally, you can specify the UtcTimeBias preference option - this is the preferred method, but it requires that you accurately set it.
You can view the imported tracklog data by selecting the main grid's 'Tracklog' tab. This is handy if you need to diagnose why you got unexpected results when geocoding photos.
You can automatically download or import tracklogs by specifying the appropriate command line parameter.
If you're using a Garmin GPS model, you can download the tracklog direct from the unit. You'll need the proper data cable for your specific model.
The program supports Garmin units having either a serial or a USB interface.
The GPS's interface mode must be set to the Garmin protocol.
When you manually save a tracklog to the internal memory of most Garmin models, the trackpoint timestamps are discarded. This behavior is a relic of the days when memory was very expensive. Without timestamps, the tracklogs are of no use. Don't save your tracklogs in your older Garmin GPS units and expect to use them with the program. Some newer Garmin models save the tracklogs to removable media in GPX format where the trackpoint timestamps are preserved. In that case, the tracklogs can be used by the program if you first enable that feature in the GPS unit. With the GPSmap 60CSx model, for example, this is done from the Tracks screen (Setup->Data Card->Log Track to Data Card).
Not all Garmin models support the transferring of altitude data. Generally speaking, the newer Garmin models (like the Etrex and GPS 60) will while the older models (like the GPS 12) will not. If you can't obtain altitude data from your unit, you can either ignore it or manually enter the altitudes for each image by double clicking on the image and then selecting 'Edit Altitude' from the resulting pop-up menu.
The program automatically detects your GPS by first looking for a USB connected device. If one is found, it's used. Otherwise, it scans all of the COM ports and tries to detect an older Garmin model.
If the program is unable to communicate with the GPS, check the following:
1. The GPS unit is turned on and is physically connected to the computer.
2. Make sure the computer port connection (USB or COM) is functional.
3. You're using a Garmin model GPS and that it's supported.
4. The GPS's transfer mode is set to Garmin's proprietary format (not NMEA).
5. Valid data exists in the GPS unit.
6. The cable connection is secure at both the GPS and at the COM port.
The program makes 3 attempts to detect the GPS and/or download the tracklog, waiting 3 second between each try.
If you don't own a supported Garmin GPS unit, you can import the tracklog from a disk file or by dragging and dropping one onto the main image grid. You can import either standard GPX files, OziExplorer track files (PLT), or tracklog files from the MN DNR Garmin program.
You can select multiple files when prompted by left-clicking while holding down the Ctrl key.
GPX File
Most GPS utility programs can export tracklogs to this industry standard format. The file extension is GPX and you can import them into RoboGEO. If a camera offset is specified, it's applied when imported.
OziExplorer PLT Files
This is the tracklog format exported by OziExplorer. The file extension is PLT and you can import them into RoboGEO. If a camera offset is specified, it's applied when imported.
DNR Garmin Format
DNR Garmin, provided by the Minnesota Department of Natural Resources, is an extension for ArcView that allows you to interface with Garmin GPS units.
To export a tracklog, follow these steps:
1. Connect the Garmin GPS to an available port and turn it on.
2. Start DNR Garmin.
3. Select the GPS port from GPS-->Set Port.
4. Is using a COM port, select the baud rate from GPS-->Set Baud Rate.
5. Set the units to feet from GPS-->Units.
6. Ensure that 'time' is selected from Track-->Track Properties-->Track.
7. Download the tracklog from Track-->Download.
8. Save it as a TXT file from File-->Save to File.
Since a DNR Garmin tracklog file contains no information with respect to the units, you must select 'feet' (not 'meters') in step #5 above.
If, per your computer's regional settings, your locale uses commas (instead of periods) for decimal points and if you select the comma delimited format in step #8, RoboGEO won't be able to parse the file. For consistency purposes, you should always select the 'Text File (Semicolon delimited) (*.txt)' format.
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