Importing ortho-corrected images with geodetic data

Tool(s): Bitmap Area

There are TIFF or JPG files providing additional information on the location and size of images, e.g. in the case of aerial photos (ortho-corrected images). This geodetic data is saved in text files with the extension TFW or JGW. There are GeoTIFF files, however, where the data is embedded in the file. Allplan detects both types automatically .

When you select a bitmap file with geodetic data using the Bitmap Area tool, you can use its scaling and drop-in point. In this case, Allplan will not prompt for the drop-in point. The TIFF or JPG file (without its extension) is automatically saved in the project's design folder and if you want, you can also save it in the office standard’s design folder.

This way, an number of ortho-corrected images can be placed correctly.

Note: In Germany the coordinates are defined as Gauss-Krüger or UTM coordinates. As bitmap areas tend to be far from the origin, it is a good idea to select the Optimize working with large coordinates option in the Options - Desktop environment - General area.

The UTM system is a global coordinate system that divides the surface of Earth between 80°S and 84°N latitude into 60 zones, each 6° of longitude in width. These individual zones are covered with a two-dimensional Cartesian coordinate system.

UTM is a worldwide standard that is used for surveying, GPS navigation, conventional maps and Google Earth/Maps. The UTM coordinate system has already replaced various national coordinate systems like the Gauss-Krüger system in Germany or the Swissgrid in Switzerland.

Allplan handles UTM, Gauss-Krüger and Swissgrid in the same way, that is as offset coordinates. In Allplan it is not necessary and thus not possible to convert UTM coordinates to other coordinate systems such as Gauss-Krüger or Swissgrid. So the same coordinate system is used for import and export.