Post

2 followers Follow
0
Avatar

Contents Not Specified

Hi there,

I downloaded the trail version of PCI Geomatica 2018 in order to re familiarize myself with what I learned in school. 

I downloaded two Landsat 8 images for the USGS and when I open them in Geomatica the three channels all say Contents Not Specified, which is not something I ever encountered during my degree. There is also a red x beside the file name for the satellite images which means that it is read only.

From what I remember there are supposed to be 7 or 8 bands shown and you can load different combinations of them into the three channels. The absence of this is causing problems when I try to do an atmospheric correction.

Under the section titled Radiometric Information where it says Calibrate Coefficients source it is automatically set to Manual Entry. When I press Band Setup it takes me to a window that lists the 8 Landsat 8 bands that I would expect to see under the raster in the maps/files directory on the left side of the program. Next to the bands are two columns for offset and gain, which are all set to 0.00000 for offset and 1.00000 for gain. It is my understanding that these values need to be different, and should be imported from the images metadata. However this information is absent, and I therefore cannot do the atmospheric correction.

If anyone knows a solution to this problem please let me know, as it is hard to re familiarize myself with the program and all the different processes if I don't have this data.

Thank you.

Adrian Ramanzin

Please sign in to leave a comment.

1 comment

1
Avatar

Hi Adrian,

What processing level did you download from EarthExplorer? "Landsat Collection 1 Level 1" is what we recommend. Also, what version of Geomatica are you using (in Focus, Help-->About).

We recommend opening Landsat imagery using the "keyfile", which is named as follows for all Landsat packaged data from USGS:
LC08_L1TP_174038_20180515_20180604_01_T1_MTL.txt

Drag/drop this file into Focus (or open in any of the Geomatica tools) and you will be prompted to open either the PAN band, the MS bands, or the Thermal band. To get all bands to load correctly (for the multi-spectral), choose "-MS"

You can review how to open Landsat in the help:
http://www.pcigeomatics.com/geomatica-help/references/gdb_r/Landsat8.html

As for the red X, that's because the file is not imported to PIX. Landsat imagery contains multiple raster channels (Pan, MS, Thermal, Quality). Once you import to PIX you will be able to add channels, or write to the file. The temporary import/view is not writable, thus the red x.

To create a full dataset with all bands at the same resolution you will need to create pansharpened data (Algorithm Librarian-->PANSHARP). This will take all the MS bands and resample them to 15m and retain the spectral content. A better algorithm to preserve radiometry while pansharpening (for scientific analysis) is MRAFUSION. It works in a similar way, but has been designed to preserve radiometric content in original imagery.

If you follow these guidelines you should be fine. If you search "Geomatica Atmospheric Correction" on YouTube you will see many examples of tutorial videos for Landsat 8 Atmospheric correction. PCI's last video on this topic was done 3 years ago, and since then our technology has changed again quite a bit, but the steps are similar. See the video here: https://youtu.be/5ATyM-bbyc8.

Good luck,

Kevin (PCI Geomatics)

Kevin Jones 1 vote
Comment actions Permalink