I am working in QGIS 2.10.1 and I have the following situation: I have some Landsat8 scenes (different paths and rows) and I want to extract their boundary. My final objective is to superimpose them to the vector of my study area, so that I can show how the scenes cover the study area and in which points they overlap. I have already tried to convert the raster into a vector, but QGIS cannot make it, it crashes or it gives me back only part of the polygon.

Is there anybody who's got an idea to solve this problem?

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    What workflows are you using to accomplish this? And, if you receive an error, please post the error text in your question. – MaryBeth Jan 4 '17 at 14:35
  • At first I was using a stack of raster layers, then I got an error saying that the maximum threshold of 2 GB had been exceeded, so now I am using only one Landsat8 band. I load the band in QGIS, then go to Raster -> Conversion -> Polygonise; I use the raster image as input and then run the tool. However, the output is not a vector covering the area of the raster, but only part of it. In addition to this, I think the result is not a polygon but a polyline, so QGIS has also got difficulties in loading it after creating it... – Laura Paladini Jan 4 '17 at 15:00
  • Sounds like image footprint extraction? plugins.qgis.org/plugins/imagefootprint_plugin – Mapperz Jan 4 '17 at 15:00
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    Perhaps try using the Raster Calculator with an expression like "raster@1" = 1. This makes all cells with a value of 1 which might make it easier for QGIS to polygonize... – Joseph Jan 4 '17 at 15:18
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    @Joseph thank you for your suggestion, maybe it's an easy but good one! I will try it as soon as possible :-) – Laura Paladini Jan 5 '17 at 17:04

You can use Plugin: Image Footprint as commented by @Mapperz. You need to download the plugin from plugin Manager, and this is how it works:

enter image description here

  1. Specify the folder (directory) where the images are located
  2. Use Valid pixels and specify the CRS of the image.
  3. The outpout will create a virtual vector file with a CRS of WGS84 as the default CRS
  4. You need to Save as the virtual vector file into a permanent file with the correct CRS that should be same as the image file.

Here is the input image file stored in the folder:

enter image description here

Here is the output footprint:

enter image description here

You can refer to the presentation: Qgis ibama imagefootprint for more information.


If you have an alpha channel in you image, you can use GDAL. to be more specific gdal_polygonize.py and use the alpha band to convert to polygon

gdal_polygonize.py image.tif "boundary.shp" -b 4 -f "ESRI Shapefile" None DN

It will return a polygon layer which has two features in it. inside and outside of alpha band. delete the outside and you have an image boundary. GDAL Polygonize


You can use "Create layer from extent" processing algorithm selecting the desired raster layer as extent source

enter image description here

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