Apply a Warp to an Image

When you warp an image file and you want to keep the colours of the original image, the new warped output image must be a Geosoft COLOR grid (*.grd) File type.

If the image of the new warped grid appears twisted or has an incorrect size, check that the warp points are in a circular order (clockwise or counter-clockwise) and that the points are correctly located within the defined map area.

If you want to warp an image file (i.e., *.tiff, *.bmp) and the file is large, you may only want to attach the warp to the file. "Attaching" the warp is suitable if you have a very large file that is stored on a CD, for instance. The warp process is repeated every time you display the file to a projected map but the original file remains unchanged.

1. On the Coordinates menu, select Georeferencing > Warp a Grid. The system displays the Warp a Grid dialog.

2. Use the Browse button next to the Input grid field to select the image you would like to warp. You may need to change the selection in the file type list in the Input Grid dialog to find the image. Click the Open button to return to the Warp a Grid dialog.

3. Use the Browse button next to the Warp definition file field to select the warp file (*.wrp) you want to use (you must have already defined this file).

4. Type in a name for the Output warped grid file. Click the Browse button to specify the image file type. Choose Geosoft default (*.grd) to retain image colours.

5. The New cell size is an optional parameter. If left blank, a default cell size is calculated to give approximately the same number of grid cells in the new image as they are in the input file. By clicking the Default button, this value may be determined, and if desired, altered.

6. Click Next. The system displays the cell size and grid dimensions for the new grid.

7. Click Finish. The system displays the warped grid or image on a new map using the projection defined in the warp file.