Calibration Points

Before a scanned map can be displayed in the correct location, it needs to be calibrated (geo-referenced). This process involves specifying the location of two known points on the map. Once the correct geographic coordinates are known for these points (called Calibration Points), ExpertGPS can calculate the coordinates of every other point on the map.

Scanned maps that were produced by other mapping programs may already be geo-referenced, in which case ExpertGPS will perform the map calibration automatically. There are three main formats for expressing map calibration information:

Calibration File Types

Map Calibration Files (.map) are used by consumer mapping programs like OziExplorer.
World Files (.jgw, *.tfw, *.pgw, *.bpw) are used by professional GIS software.
GeoTIFF Files (.tif) embed the calibration information in the TIFF image (not currently supported by ExpertGPS).

If the scanned map does not have a calibration file, you will need to calibrate it manually before it can be properly displayed in ExpertGPS.

ExpertGPS works with hundreds of GPS receivers, including all Garmin Drive, nüvi, eTrex, Colorado, Dakota, echoMAP, GPSMAP, Edge, Forerunner, Montana, Oregon, and Rino models, Magellan eXplorist GPS receivers, and Lowrance HDS, Elite, and HOOK GPS chartplotters and fishfinders. Download ExpertGPS

Find your GPS on the ExpertGPS compatibility list.