Loading Mars Gravity Data MRO 2016 data

[BrianK]

Hi, I am trying to load .img data from mro-m-rss-5-sdp-v1/mrors_1xxx/data/rsdmap/ into a Win 10 /ArcGIS 10.5 environment. I have been treating these data e.g. http://pds-geosciences.wustl.edu/mro/mro-m-rss-5-sdp-v1/mrors_1xxx/data/rsdmap/ggmro_120_anom_100.img as img files and keep getting the message "file corrupt" when I try to mount them. I have used a selection of analysis tools to try and find why these files are not loading. Any suggestions welcome please

[June Wang]

Hi BrianK,

ArcGIS doesn’t read all of the PDS IMG format data. Some may work and some may not. GDAL is a standard application for changing formats for PDS IMG data.
http://www.gdal.org/ (general information and the link to download)
http://www.gdal.org/gdal_translate.html (basic GDAL commands)

I used Gdal to translate this PDS IMG data product to a Geotif image. Since the MAP_SCALE field has value of "N/A" in the product label, Gdal cannot recognize the pixel size for this data product and cannot make a successful format change for this data product.

The data product label actually defined a real value for the field MAP_RESOLUTION. Based on this value and other parameters in the label, there are two ways to calculate the MAP_SCALE at equator for SIMPLE CYLINDRICAL projection. Both way get the same result of 3704.461337 <m/pix>.  
               A_AXIS_RADIUS                = 3396.0 <km>
               LINE_SAMPLES               = 5760
               MAP_RESOLUTION               = 16 <pix/deg>

1)      MAP_SCALE = 1/180*pi* RADIUS/ MAP_RESOLUTION     

2)      MAP_SCALE = 2*pi* RADIUS/ LINE_SAMPLES              

I used this number to update the MAP_SCALE field in the data product label, then ran gdal commands below to view the information of this data and do format translate from PDS IMG to Geotif. You can later load this Geotif into ArcGIS.

             Gdalinfo D:\test\data\mro_rss\ggmro_120_anom_100.lbl
             Gdal_translate -of GTiff D:\test\data\mro_rss\ggmro_120_anom_100.lbl D:\test\data\mro_rss\ggmro_120_anom_100.tif

Feel free to let me know if you need more help. Thanks,

June