SRTMGL1N repeating tiles issue

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axel_corseaux
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Joined: Mon Dec 06, 2021 4:35 am America/New_York

SRTMGL1N repeating tiles issue

by axel_corseaux » Wed Dec 08, 2021 5:10 am America/New_York

Hello everybody,
I tried using the SRTMGL1N v003 product (found at https://lpdaac.usgs.gov/products/srtmgl1nv003/). I encounter issues trying to use this product, finding repeating tiles over the North of Africa.

I tried to download tiles using the Data Pool (at https://e4ftl01.cr.usgs.gov/MEASURES/SR ... age_1.html). I then imported these tiles into the QGIS software. In the attached "num_files_into_qgis.jpg" image are shown the "N22W017.num" and "N22W016.num" tiles. You can see that the right tile (N22W016.num) looks similar to the left tile (N22W017.num), repeating the shape of the shoreline.

Then, I tried requesting a GeoTiff raster over a larger bounding box using the AppEEARS tool (see attached "appears_request_example.jpg" for the request).
Again, we can see repeating tiles over this area (see attached "appears_geotiff_into_qgis.jpg"). More precisely, it seems that the water masking is repeated over these tiles, but the other pixels seem correct.

Did I miss something when downloading / importing these tiles ?
Attachments
Shows the result of an AppEEARS request of SRTMGL1N over the North of Africa.
Shows the result of an AppEEARS request of SRTMGL1N over the North of Africa.
appears_geotiff_into_qgis.jpg (487.36 KiB) Not viewed yet
Shows an AppEEARS request of SRTMGL1N over the North of Africa.
Shows an AppEEARS request of SRTMGL1N over the North of Africa.
appears_request_example.jpg (97.3 KiB) Not viewed yet
Shows the "N22W017.num" (left) and "N22W016.num" (right) tiles.
Shows the "N22W017.num" (left) and "N22W016.num" (right) tiles.
num_files_into_qgis.jpg (312.38 KiB) Not viewed yet

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LP DAAC - jwilson
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Posts: 81
Joined: Mon Sep 30, 2019 12:39 pm America/New_York
Answers: 1

Re: SRTMGL1N repeating tiles issue

by LP DAAC - jwilson » Wed Dec 08, 2021 8:57 am America/New_York

We have forwarded your inquiry to our Subject Matter Expert for guidance.
Thank you,
Janice

axel_corseaux
Posts: 2
Joined: Mon Dec 06, 2021 4:35 am America/New_York

Re: SRTMGL1N repeating tiles issue

by axel_corseaux » Tue Dec 14, 2021 9:36 am America/New_York

Hello,
Thank you for the quick reply. Is there any update concerning this request ? We would really like to use this product for our projects.
Kind regards,
Axel

LP DAAC - jwilson
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Posts: 81
Joined: Mon Sep 30, 2019 12:39 pm America/New_York
Answers: 1

Re: SRTMGL1N repeating tiles issue

by LP DAAC - jwilson » Mon Dec 20, 2021 4:06 pm America/New_York

Our Subject Matter Expert has sent your inquiry to the PI to provide some clarity on what is going on here or if there may be a fix for the issue?
Thank you for your patience.
Janice

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