Working with Images & Maps
Updated May 03, 2016
This article applies to:
- Terrain 3D
- Terrain Forestry
- RoadEng Civil
- RoadEng Forestry
Digital images (or bitmaps) can be used to enhance the visual impact of a map or drawing. They can also be used to extract and/or represent geometric information. The Terrain Module allows you to import bitmap images in various standard formats such as BMP, JPG or TIF. In order to use images for mapping they must be georeferenced.
In GIS terminology Georeferenced means ‘tied to a specific geographic location on the earth’. A georeferenced image is one that has been scaled, rotated and stretched into position to correlate to a map projection. It may be an aerial photograph, a scanned paper map or a satellite image. What makes a georeferenced image distinct from other raster images is the inclusion of coordinate data used to locate its exact geographic position. This additional coordinate information can either be encoded in the image (e.g. Geotif), or as a separate “world” file (e.g. *.tfw).
Standard images (*.bmp, *.jpg etc) do not contain georeference information. However, images from mapping or GIS sources contain this information. If an image is not georeferenced, Terrain Tools can be used to create this information. This example will explore several methods for georeferencing an image.
To do this example Mapping and Drafting, Import Basic and Export Basic function groups must be enabled. See Function Groups for additional information.
In this section: