[ARCHIVE] How to rename GLCF Landsat 7 GeoTiff files so they match the standard Landsat naming convention

Topic:
This article describes how to rename single band GeoTIFF files so that Landsat 7 data distributed by the University of Maryland Global Land Cover Facility (GLCF) can be properly interpreted by ENVI's Landsat calibration tools.

Discussion:
ENVI's Landsat calibration tools can ingest raw data in several forms, including multiple single band GeoTIFFs. This form of data distribution has become increasingly common, especially in regards to the large amount of free Landsat 7 data available through the GLCF. The naming convention used by the GLCF for single band Landsat GeoTIFFs does not match that used by the USGS. Where this difference becomes important is when a user attempts to calibrate the single band data to top of atmosphere reflectance. This is because the calibration for each band requires the inputting of a unique scaling factor. ENVI determines the correct scaling factor to use by parsing the filename in a very particular way, looking for a designator which indicates the band number. If ENVI does not know which band it is dealing with, it will always assume that the input is from Band 1 and calibrate it accordingly. Because the scaling factor can vary significantly from band to band, this assumption will lead to erroneous calibration results. This is what happens with GLCF Landsat data because of how the files are named. A workaround to this problem is to rename each single band GeoTIFF so that it matches the standard Landsat naming convention. So, for example, Band 3 for a Landsat 7 scene could look like this:

p089r066_7t20000906_z57_nn30.tif

where p089 is the path, r066 is the row, 7 is the sensor, t is the file type (TIFF), 20000906 is the year/month/day, z57 is the UTM zone, and nn30 is the band (3). The UTM zone used is always in the northern hemisphere--even if the scene coverage is in the southern hemisphere.

In standard Landsat form, that same Band 3 file looks like this:

L71089066_06620000906_B30.TIF

where L7 is the sensor, 1 is the file type (TIFF), 089 is the path, 066_066 is the starting and ending row (always the same in this case), 20000906 is the year/month/day, and B30 is the band (3). So, for an entire set of GLCF TIFF images for the scene in question, the file names would look like this:

L71089066_06620000906_B10.TIF
L71089066_06620000906_B20.TIF
L71089066_06620000906_B30.TIF
L71089066_06620000906_B40.TIF
L71089066_06620000906_B50.TIF
L71089066_06620000906_B61.TIF
L71089066_06620000906_B62.TIF
L71089066_06620000906_B70.TIF
L71089066_06620000906_B80.TIF

If the files are renamed in this way, ENVI will properly interpret the filename and use the correct scaling factor when performing a calibration to reflectance. This filename issue does not affect calibration to radiance.

 

reviewed on 9/9/2014 by CS