Importing ground control points from a file

During manual GCP collection, you can import ground control points (GCP) from a PCIDSK (.pix) or a text file. When you select PIX/Text file in the Ground control source list in the GCP Collection window, the Read GCPs from PIX/Text File window is displayed automatically.

In the GCP input file box, type the path and file name of the text file or the PCIDSK file containing the GCP segment or, to select the file, click Select.
The layout of the file is displayed under Preview.
To change the format of the GCPs, in the Format box, type or select the string representing the layout of the file, and then click Apply Format.
Each format variable in the string represents a field in the text file. For more information about the format, see Understanding formats for text files containing GCPs.
To view or modify the projection of the GCPs being imported, click View/Edit.
Click OK.

If the file contains the pixel and line coordinates, and the ground coordinates, all the points corresponding to the raw image are transferred to the project. After the points are transferred, in the GCP Collection window, you can add elevation values to the points or change their positions. If the file does not contain the pixel and line coordinates, you must manually enter them in the GCP Collection window.