ADRG, .thf

NGA ARC Digitized Raster Graphics (ADRG), loaded from .thf files.  ADRG is a US military format, often used for raster scans of military charts.   Remarkably, for such an old format, ADRG files will usually provide projection information so that the images created from them will have the correct projection assigned on import.

 

ADRG files typically come in hierarchies of folders containing many constituent files.   The .thf or .THF file is the guiding file that we will choose.

 

dlg_import_adrg_thf.png

 

To import from ADRG format:

 

  1. Choose File-Import from the main menu.

  2. In the Import dialog browse to the folder containing data of interest.

  3. Double-click the file ending in .thf for the data of interest.

  4. Tables and images will be created.

 

 

eg_import_adrg_thf01_01.png

 

The IMG file above is the main image.  The other images provide scans of legends and similar information from the paper map that was scanned.

 

We can double-click on images that are created to view them.   For a more interesting display, we first create a new data source using a Bing street maps imageserver as shown in the Example: An Imageserver Tutorial topic.   We then create a map and drag and drop the Bing layer into the map, and then we drag and drop the TPUS0102.IMG image into the map.

 

eg_import_adrg_thf01_02.png

 

The image appears using the correct projection.   

 

eg_import_adrg_thf01_03.png

 

Zooming in we see it is a tactical air navigation chart, scanned and reasonably high resolution.   All text is very clear.

 

eg_import_adrg_thf01_04.png

 

Other images imported from the file provide additional information that was scanned from the paper chart.

 

See Also

Maps

 

Images

 

Example: Spectacular Images and Data from Web Servers

 

Example: An Imageserver Tutorial