Bit Flag Renderer

About

The Bit Flag Renderer is a QGIS Plugin to visualize bit flags in raster quality images.

The Bit Flag Renderer is developed at Humboldt-Universität zu Berlin, Earth Observation Lab as part of the Land Use Monitoring System (LUMOS) project, funded by the Belgian Science Policy Office as part of the Stereo-III research program (grant no. SR/01/349).

Features

• visualizes bit flags consisting of 1 to 3 bits (from 2 (on/off) to 8 different states)
• layer legend shows flag state colors
• predefined flag schemes, e.g. for [Landsat Quality Assessment (QA) bands](https://www.usgs.gov/landsat-missions/landsat-surface-reflectance-quality-assessment)
• allows to specify, save and reload flag schemes
• Documentation [https://bit-flag-renderer.readthedocs.io/en/latest](https://bit-flag-renderer.readthedocs.io/en/latest)
• Repository [https://bitbucket.org/jakimowb/bit-flag-renderer](https://bitbucket.org/jakimowb/bit-flag-renderer)

How to Use

Clouds and shadows according to the Landsat quality assessment (QA) flag layer, visualized with the Bit Flag Renderer panel

To visualize bit flags of a byte/integer raster layer, select this layer in the QGIS raster layer tree and open the QGIS Layer Styling Panel. Then:

1. Select the Bit Flag Renderer sub panel

2. Add the number of Bit Flag parameter that you like to show or open load a pre-defined scheme of bit flags

3. Specify for each parameter (double click) the first bit position and the total number of bit the parameter is using. The total number of bits controls the number of possible states a parameter can have per pixel, e.g.

   • ‘0’ for the first bit = 2 flag states
   • ‘1’ for the second bit = 2 flag states
   • ‘1-2’ for bit 1 and 2 = 2^2 = 4 flag states
   • ‘1-3’ for bit 1, 2 and 3 = 2^3 = 8 flag states

Now control the visibility of flag states in the map and layer legend:

• Change flag state visibility by checking/unchecking them in the tree view
• Define names of parameters and flag state (double click)
• Define flag state colors (double click)

Online documentation	https://readthedocs.org/projects/bit-flag-renderer/
Source Code	https://bitbucket.org/jakimowb/bit-flag-renderer
Issue tracker	https://bitbucket.org/jakimowb/bit-flag-renderer/issues

License and Use

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License Version 3 (GNU GPL-3) , as published by the Free Software Foundation. See also License.