![]() ![]() False NorthingĮnter the false northing used by this projection. False EastingĮnter the false easting used by this projection. Therefore, the vertical Central MeridianĮnter the latitude of the natural origin of the map. In the example below, the 0º and 20º East lines of longitude slope away from the vertical at the same angle. If the Central Meridian is not explicitly listed in the map margin, determine the line of longitude that is vertical on the map. This is the only line of longitude on the map that is vertical. The standard parallels for maps showing the 48 conterminous US states are typically 29º 30' and 45º 30' North.Įnter the longitude of the central meridian. The standard parallels for maps showing all 50 US states are typically 20º and 60º North. Standard ParallelsĮnter the latitude of the two standard parallels, in degrees and decimal minutes. It's only when you start working with maps that cover a whole country or continent that the distortion due to the Earth's curvature starts to make the exact projection details necessary. If your map doesn't have projection information listed, and it covers a small area (like a county, town, or regional park), you can safely choose the Mercator projection and get reasonable results. ![]() This information should be printed in the margin or a corner of your map. In order for your scanned map to display correctly, ExpertGPS needs to know the details of the projection used when the map was printed. Click the Parameters button and enter the projection details for the map. Parameters If the Parameters button appears, ExpertGPS requires additional information about the map projection. This information should be printed on the margin of the map.ĭatum Select the datum used on the map. Select the projection that this map uses. Need to manually calibrate the map so that your GPS data appears correctly on it. If your scanned map came with a calibration file (worldfile or map calibration file), it will automatically be detected and used. Specify the projection information located on the collar of your map. In the Edit Scanned Map dialog, enter a descriptive name for your map, and Select a JPEG, TIFF, PNG, or Bitmap image of your map. To add a new map to the Scanned Map Library, click Add and Calibrate a New Scanned Map on the Map menu, under Scanned Paper Maps and Digital Charts. Before you can use your map in ExpertGPS, it must be added to the Map Library and calibrated. ![]()
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