AMATEUR MODES OF OPERATION
APRS MAP DATA
.GEO and .INF FILES
Updated 5 Oct 2006, 0200 UTC
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AMATEUR MODES OF OPERATION
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Toporama Maps .geo/.inf file information Zipped .geo or .inf files for Toporama maps .geo and .inf files in general One type of map used in APRS programs is one that is scanned in and saved in one of many formats as an image file. These image files are usually in the form of a .jpg, .bmp., .gif, or .png. Unlike vector maps such as those in the .map format, where the information is coded within the file, the APRS program needs to be told where our image map fits in the world. A separate data file with this information has to be created giving reference points in the image to geographical co-ordinates. Normally two points are chosen, upper left and a point towards the lower right of the image and then these are referenced to the lat and long of these points on the image. WinAPRS uses Decimal Degrees and a .geo file. Inside the .geo file is the filename of the map image, two reference points (x/y pixels), lat and long in decimal degrees. UI-View32 uses Degrees, Minutes, Seconds, and an .inf file. Inside the .inf file are the geographical coordinates of the upper left and lower right corners and a title for the image map. For example, if you have downloaded the topographical map sheet 031C07 - Sydenham at 1:50,000, you will need a .geo file for WinAPRS or an .inf file for UI-View32. Without these files the image map is useless to APRS. Under WinAPRS, you would place 031c07.gif and 031c07.geo into the "images" directory under WinAPRS, or in a subdirectory of the images directory. In UI-View32, you would place 031c07.gif and 031c07.inf into the "Maps" directory under WinAPRS, or in a subdirectory of the Maps directory. Now when you use your APRS program, the image map is available. Note that you can rename your files for example 031c07 doesn't tell you much about the map, so to make it easier you can rename both the .gif and .geo/.inf file to a more descriptive name, in this case, we will call them 031c07_sydenham.gif and 031c07_sydenham.geo or.inf. Toporama Maps .geo/.inf files Topographical maps correspond to the published map sheets and Landsat 7 maps of the same sheets are available at: Natural Resources Canada's Toporama web site in both 1:250,000 and 1:50,000 scales. These map images are free to use, however, ensure you read the legalese of the license and modification use as these are copyrighted maps! The topographical maps/orthoimages are GIF images and do not show all the details of the normal map sheet but are detailed enough for your GPS/APRS/Navigation Programs. There are no Grid lines, borders or legends on the images, and any information on the American side of the border is missing from the images. Landsat 7 (orthoimage) map images do show the American side where applicable.
Manually creating .geo and .inf files is a tedious, time consuming task,
requiring converting between decimal degrees and degrees, minutes, seconds
format for the geographical lat/longs.
As more data is manually entered and each map has its .geo/.inf files
created, they will be posted here. If you have some time and would like to
help enter the data, download the Excel spreadsheet "toporama_blank_raw_data.zip"
and when you have the data entered email it to the address in the file and if
yours is the first to arrive, you will be given credit for the maps you have
collected the data. Hopefully we will be able to have GEO and INF files
for all the map sheets of Canada!! |
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