The program 3DField can overlay a contour map on bitmap base map. One can generate a list of files from which to choose a background. Base map can be attached with contour map and scaled together.

The Objects | Base Map menu opens the dialog.

The Add button adds a file in the list. The list can contain positions in the same file, but at other attachment to a contour map. The Delete button removes a selected line from the list. The Visible box shows or hides background image on a map. Set as Default automatically places the selected image on a new map. Rename gives a position a new name.

The background can be stretched to a full window, placed at the center or adhered to two coordinate points with the Assigning Coordinates button.

To attach the base map to the points, please, follow the next step:

1. Press the Assigning Coordinates button
2. Double-click (or to enter manually) the first point's location (x₁, y₁) in pixels. Enter the coordinates (X₁, Y₁) for this location in units relative to the data points. OK
3. Double-click (or to enter manually) the second point's location (x₂, y₂) in pixels. Enter the coordinates (X₂, Y₂) for this location in units relative to the data points. OK