Talk:Land Cover/Use Classification using the Semi-Automatic Classification Plugin for QGIS

From AWF-Wiki
Revision as of 10:35, 26 November 2018 by Hfuchs (Talk | contribs)

Jump to: navigation, search

To be updated for QGIS 3

  • For these tasks you may also use one processing toolbox model.

Qgis convert boa model.png

  • Open the Processing --> Toolbox and Models --> Tools --> Add model from file. Load the previously downloaded model.
  • The model should appear in the Models tab.
  • Double click to open the model.
  • Assign the layers to the right band numbers.
  • Click OK



Note: In order to use the batch process in the Raster Calculator you need to first create all of the 9 band split tifs using Translate. Here again you can use the batch processing option.

This batch does not work probably because there seems to be a bug in the processing toolbox raster calculator module: it does not correctly convert the datatype UInt16 to float32:

  1. Load the multiband raster file Subset_S2A_MSIL2A_20170619T.tif available in the course data. This contains all 13 bands of Sentinel-2 scene.
  2. Follow Split stack to extract bands 2, 3, 4, 5, 6, 7, 8, 11 and 12, using the multiband raster file Subset_S2A_MSIL2A_20170619T.tif as input layer.
  3. In the processing toolbar, type Raster calculator into the search field to find the GDAL\OGR --> Raster calculator tool and open it.
  • Click the button Run as batch process..., and use Add row Add rows.PNG button to add enough processing rows.
  • Click the button ... of Input layer A to select the single extracted bands as input layers (i.e. one per row).

Convert DN to reflectance.png

  • Enter and repeat the expression A/10000 under Calculation in gdalnumeric syntax using +-/* or any numpy array functions (i.e. logical_and()) and set Output raster type to Float32

Batch2.png

  • Click the button ... of Calculated to save output file
  • Click Run
Personal tools
Namespaces

Variants
Actions
Navigation
Development
Toolbox
Print/export