INTERNAL: UNDER CONSTRUCTION - ENVI 5: Opening a TIF/TFW file
Anonym
Topic
A TIFF file with no embedded geographic information will often come wiht a TIFF world file (.tfw) that provides this information. However, a .tfw file only includes the coordinate of the tie point, but no information is provided about the projection type. When you open the TIF file in ENVI, the image will not be projected. To solve this, you can edit the header file which will allow the image to be projected and ready to use, with the map coordinates attached to the header file. This help article discusses how you can enter the map information from your .tfw file into the ENVI header.
Discussion
After opening the TIF file in the ENVI interface, do as follows:
1. In the toolbox, go to Raster Management > Edit ENVI header
2. In the Edit header input file dialog, select the TIF image
3. In the Header Info dialog, go to Edit Attributes > Map Info
4. In the Map Coordinate of Tie Point section, click on Change Projection, and select the right projection/datum (i.e. UTM / WGS-84) (you must know this information or get it from the data provider).
5. click on OK to save the information to the ENVI header file (.hdr).
The image will be closed by the ENVI interface, due to the modifications made in the header. You can use the Data Manager to open again the image, which should now projected and associated to the proper map info.
You will notice a .hdr file has been created by the system, and located in the same folder as the TIF/TFW files. Next time the image will be opened in ENVI, the map information written in the hdr file will be used and the image will properly projected.