Display Image on Map

Use the Image (bmp, tiff, etc.) option (geogxnet.dll(Geosoft.GX.Map.DisplayImage;Run)*) from the menus Grid and Image > Display on Map or Map > Import to place an image on a map.

Display Image dialog options

Image name	Select the image file to display. Use the Browse tool to pick the correct image file type from the drop-down list, then select the file. If a grid is specified, it will be displayed using the default grid colour table specified in the General Settings dialog. For a list of supported image formats see the topic Supported Data Formats. Script Parameter: GRIDIMG.IMAGE
Background colour	Select the background colour option: none, white, or black. Points in these colours will be treated as dummies. See Application Notes below for more details. Script Parameter: GRIDIMG.DUMMY [0: None, 1: White, 2: Black]
Registration	Georeferenced images, such as grid files or GeoTIFF files, can be plotted in their default locations. Other images should be placed where you want them. Choose how to place the image on the current map:  Default: the image is placed in the default location. If the "Default" option is selected and the aspect ratio of the selected image differs from that of the active map, the [More] button will become available. Click the button to expand the section and decide if the image to be displayed on the current map should or should not inherit the aspect ratio of the map. Fit to area: the image is placed within an area that is interactively defined. Script Parameter: GRIDIMG.REG [0: Default, 1: Fit to area]
[New Map] [Current Map]	Click the New Map button to display the image on a new map. If the map already exists, you will be prompted to overwrite or provide a different name. Click the Current Map button to display the image on the active map. Script Parameter: GRIDIMG.NEW [0: Current map, 1: New map]
[More]
Map aspect ratio X/Y	Informational field that displays the aspect ratio of the current map (note that X/Y is ≠1/1 when the X & Y axes are different).
Reconcile aspect ratio	You have the option to either preserve the image aspect ratio or scale it to match the existing map aspect ratio: Preserve image aspect ratio - the aspect ratio of the map is ignored, and the image is displayed on the map based on its own aspect ratio. Scale image to map aspect ratio - the map aspect ratio is applied to the image, and the rescaled image is displayed on the map. Script Parameter: GRIDIMG.IGNORE_IMG_ASPECT [0: Scale, 1: Preserve (default)]

Application Notes

There are several software packages that create and manipulate images. Many such systems use very common extensions such as .IMG, while they generate files in entirely different formats. Some of these formats are proprietary and can not be supported. In such an instance, you are still permitted to select the file; however, in the next step, a message appears stating that the format is not supported, and the import is then terminated.

Add Raster Images to Maps

Oasis montaj supports a variety of raster image formats. Images are defined as files containing location (X and Y) and colour values. Values are not interpolated. Examples of images are standard raster graphics, such as Windows bitmaps (*.BMP) or tagged image format (*.TIF) files.

Large raster images now include enhanced image caching performance. Maps with large raster images may take a few seconds longer to open the first time you open them; you may notice the progress bar message "Copying grid data to pager" followed by "Caching grid". However, after the initial loading of the raster file, zooming and panning around and on the map are instantaneous!

Accessing ER Mapper Bands

Oasis montaj enables you to work with a variety of grid and image formats — freely importing them, specifying certain grid parameters (such as specific bands) and exporting them as required. The procedure for accessing (importing) an image by placing it on a map is similar to the method for importing a grid.

The basic mechanism for accessing grids and images is provided through a special technology called DAT. DATs are DLLs that provide interfaces to a variety of image and grid formats. Each DAT has a 3-letter identifier and a number of parameters that can be used to "decorate" the file name when accessing a file for import or export.

For example, to access the third band of a TM image in an ER Mapper image named "CITY.ERS", you would "decorate" the name as follows:

City.ers(ERM;band=3)

The first parameter in the decoration block (inside the parentheses) is always the 3-letter DAT identifier, which you must supply any time you want to specify a decoration. If you do not specify a decoration, the default DAT type is taken from the "DAT Settings" parameter in the Advanced Settings dialog.

For a complete list of decorations currently available for use in the system see the topic XGD DAT Qualifiers.

Background Colour

Points in the background colours will be treated as dummies, meaning that:

• If you select "White", any pixel that is white on the input image will become transparent on the map.
• If you select "Black", any pixel that is black on the input image will become transparent on the map.
• If you select "None", all pixels of the input image will be represented with the same colour on the map, i.e. any pixel that is white in the image will remain as white on the map.

Interactively Fitting an Image or Grid to an Area

When you place an image or grid on a map, the system assumes you are using the default registration system as defined in the grid or image header. If you want to position the grid interactively, select the option Fit to area; then use the mouse to define a rectangular area on the map and the system will fit the grid (or image) exactly to this area.