Dulci Avouris
New Member
Posts:51  
| 28 Aug 2018 10:06 AM |
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Hello!
I am using ENVI 5.4.1 & the open_as function to import Landsat 8 OLI Surface Reflectance files in GeoTIFF format with an _MTL.txt is not reading in the data. I know that there has been some support for that format, but the program is not recognizing the MTL.txt files as valid. Importing the GeoTIFFs and creating a metafile has created a host of problems because the data periodically is moved around on our computer, so while we have used this work-around for a couple of years, it is not ideal.
Is the Landsat 8 import function supposed to be working, or is there just a bug? We cannot upgrade to ENVI 5.5 at this time.
Thank you!
-dulci
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MariM
Veteran Member
Posts:2396 
| 28 Aug 2018 01:49 PM |
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What is the error you receive when opening the metadata file? Is there also an XML file present in the data directory with the tiff and metadata files? There are instances where the MTL and XML files reference different bands/files that do not exist and can produce an error. These were resolved in ENVI 5.5 by modifying the files read from the MTL file. You could possibly edit the MTL to match the actual file names present in the directory, if it is the same issue.
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Dulci Avouris
New Member
Posts:51
| 30 Aug 2018 09:13 AM |
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The original _MTL.txt file does not show up on the list of potential files to open when I use the Landsat GeoTIFF with Metadata option. If I edit the filename to have lowercase letters: _mtl.txt it does show up in the list of recognized files. However, when I open it, it tells me 'variable undefined - ignore' . I click OK & nothing opens up. I edited the _mtl.txt file to read in the surface reflectance bands names, but it is still not right.
So I guess it could be a two-pronged problem: ENVI isn't recognizing filenames that it should, and potentially Landsat processing is not providing the correct _MTL files.
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Dulci Avouris
New Member
Posts:51
| 30 Aug 2018 09:15 AM |
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I should add - the .xml file is available, but I can't find how to read that in with ENVI 5.4.1 - from previous forum posts, I gathered that the .xml for Landsat 8 surface reflectance is not supported in 5.4.1. Thank you for your help!
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MariM
Veteran Member
Posts:2396
| 30 Aug 2018 09:22 AM |
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We have seen the IGNORE error and the solution is to upgrade to ENVI 5.5. There are cases where you can open via the XML but not always as there are quite a variety of XML updates out there. If you are unable to upgrade, then the solution would be to stack the bands manually using something like Layer Stacking resulting in an ENVI format file.
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Dulci Avouris
New Member
Posts:51
| 30 Aug 2018 03:08 PM |
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Ok. Thank you for the help! I appreciate it.
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