NDF (NLAPS Data Format)

The National Landsat Archive Production System Data Format (NLAPS Data Format) is the distribution format used by the USGS (Eros Data Center) for Landsat data. It apparently supersedes use of Eosat Fast Format from the Eros Data Center. NDF format is a CDROM raster image format supported for read, but not for creation.

NDF data sets consist of a number of files, as shown below. In order to read an NDF data set it is necessary to select the header file (the one with the extension `.hd'). Once this is selected, each of the band files (.i1, .i2, etc.) will be opened. If the naming conventions are different than those shown here, it may not be possible to read the data set.

-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:33 01196082.dat
-r-xr-xr-x  1 11431  24       889 Sep 18 15:33 224242.sum
-rwxrwxr-x  1 11431  24       588 Sep 19 08:27 YMTRANS.TBL
-r-xr-xr-x  1 11431  24      2565 Sep 18 15:33 lt501704.hd <-- Header File
-r-xr-xr-x  1 11431  24    100836 Sep 18 15:33 lt501704.hi
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:36 lt501704.i1
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:38 lt501704.i2
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:40 lt501704.i3
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:43 lt501704.i4
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:45 lt501704.i5
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:48 lt501704.i6
-r-xr-xr-x  1 11431  24  44073342 Sep 18 15:50 lt501704.i7
-r-xr-xr-x  1 11431  24     20836 Sep 18 15:50 lt501704.wo

NDF data can potentially have many variations, however the translator has only been tested with a few typical output products. Some precision geocoded products may include a DEM; these cannot be read.

All the information from the header file will be imported as a text segment in order that the information is preserved with the data set for later review. A ground control point segment will be generated with five points representing the four corner points and the central reference point of the image. The data sets can be easily geocoded using OrthoEngine and these included control points. However, even geocoded products are produced with some rotation from north, therefore it is not possible to treat the original data set as geocoded.

CDNLAPS can be used to import NLAPS data with the ephemeris data required for satellite ortho correction preserved. MNLAPS can be used to read NLAPS tapes. CDNLAPS and MNLAPS are part of the satellite ortho correction package.