Using the math model for georeferencing

When a math model is used to set the georeferencing, the image is displayed without correction in the viewer. Accurate ground coordinates are calculated for each pixel using the pixel and line coordinates, the math model, and the digital elevation model (DEM), or an approximate elevation value that you provide.

To use the math model for georeferencing

In the Source of georeferencing list, select the segment containing the math model that you want to use in the area.
The projection, bounds, upper-left coordinate, lower-right coordinate, and pixel sizes are displayed under Georeferencing Information.
To use a DEM as the source for your elevation values, click DEM, and then do the following:
1. In the File box, type the path and file name of the DEM or, to select a file, click Browse.
2. In the Layer list, select the layer that contains the DEM.
3. In the NoData (background) value box, type the value that represents the pixels that lie outside the DEM area.
  By doing so, the pixels are not mistaken for elevation values.
To use an estimate of the elevation instead of the DEM, click Approximate elevation, and then do the following:
1. In the Elevation value box, type the elevation value that you want to use.
  If you do not enter an elevation value, a value of 0 meters (Mean Sea Level) is used by default.
2. In the Elevation reference box, select Mean Sea Level (MSL) if the elevation values were calculated based on the geoid; select Ellipsoid (ELL) if the elevation values were calculated based on an ellipsoidal model of the Earth.
3. In the Elevation units box, select a measurement unit for the elevation values.