Raster Data Plotting¶
Raster Data Plotting is a QGIS plugin for creating plots visualizing raster data for all pixels currently visible inside the map canvas.
The Raster Data Plotting plugin adds a panel for creating plots (e.g. 2-d scatter/density plot) visualizing all visible pixel for selected raster layers and bands. The plot data is adapting in real-time, whenever the map canvas extent changes.
- In QGIS select QGIS > Plugins > Manage and Install Plugins…, search for RasterDataPlotting and install the plugin.
- In the toolbar click to show the Raster Data Plotting panel.
- Create a Scatter Plot:
- Select two raster bands (e.g. Red and NIR bands of a Landsat 8 image).
- Interactive plotting:
Zoom to the raster layer and navigate to specific locations of your choice. Notice how the plot is adopting to the map canvas content.
Scatter / Density Plot¶
The scatter plot is using Cartesian coordinates to display values for two raster bands. Data density is derived by 2-d histogram binning. The number of points falling onto the same bin are color-coded.
Spectral region of interests¶
Create spectral region of interests (spectral ROI) inside the scatter plot to overlay/colorize pixels in the map canvas with the same spectral characteristics.
E.g., in this Landsat 8 image, it is quite easy to identify Water and Forest pixels inside a Red vs. NIR scatter plot:
Map Canvas: Landsat 8 in true-color composition (left) and together with spectral ROIs overlay (right).
Spatial region of interests¶
Select spatial region of interests (spatial ROI) to focus the analysis on specific regions in the map canvas (e.g. urban, forest, water or agriculture areas).
Given a Landsat 8 image and some landcover polygons, different kinds of plots are available.
MapCanvas: Landsat 8 in true- color composition and four different landcover polygons as spatial ROISs.
Scatter Plots: density of all pixels (left), density for spatial ROIs (middle), and colorized scatter for spatial ROIs (right).
Note that for coarser binnings, it is very likely that points from different ROIs will fall into the same bin. In those cases, the bin color is given by a weighted average of the involved ROI colors.
Spectral Profile Plot¶
For Temporal Profile Plots install the RasterTimeseriesManager plugin.