SPOT images are satellite (raster) images of the earth. SPOT Image Corporation offers these images under the name SPOTView™. SPOT images work well with MapInfo Pro and are particularly useful when scant vector data is available for a geographic region, or when you want to super-impose vector data on top of a highly accurate raster backdrop. Additionally, MapInfo Pro works with the Geospot™, format.
This section assumes you have some familiarity with manually registering raster images. If the subject is new to you, see Registering the Coordinates of a Raster Image in this user guide.
The process described here is not foolproof. Because of inaccuracies in the header file settings or problems in companion vector data, you may occasionally need to manually readjust the control points using the Register Raster Image dialog box. Refer to Register Raster Image.
Part of registering a SPOT image is assigning the proper coordinate system. The standard coordinate systems for most US SPOT images are Universal Transverse Mercator and State Plane. But in other cases a SPOT image may use a different coordinate system and may even require that you add a new coordinate system to MapInfo Pro. This section will help you identify what settings to use for a SPOT image, as well as when to add a coordinate system to MapInfo Pro, should you need to. A SPOT image consists of several files, not all of which are required by MapInfo Pro. Here are the files that MapInfo Pro uses:
- .HDR file - A header file in ASCII form that contains information about the image's size, coordinate system, (SPOTView only) and location on the earth.
- .BIL file - A binary file that contains the image's raw raster data.
- .CLR file - A palette file that contains a list of suggested colors to be used with the image. This file is only provided with color images, and MapInfo Pro reads the contents of this file when present.
A report (.REP) file in ASCII form also accompanies each Geospot product. Although MapInfo Pro does not read this file, you may find that it too contains useful information for registering the image, particularly image rotation and coordinate system information.