Tutorial Zonal Statistics and Area Computations
Voltooingsvoorwaarden
1. Introduction
For many studies it is important to know the statistics of a continuous raster for discrete units (in raster or vector format). For example, the average elevation per subcatchment, the maximum NDVI per land-cover class, etc. In this tutorial you'll explore several tools available in QGIS for calculating zonal statistics and compute surface areas.
Learning objectives
After this lesson you will be able to:
- calculate zonal statistics from a continuous raster layer using areas defined by a polygon vector layer
- calculate zonal statistics from a continuous raster layer using zones in a discrete raster layer
- calculate the surface area of classes in a discrete raster
- calculate the surface area of classes in a discrete raster per area defined by a polygon vector layer
- calculate other univariate statistics from raster layers
Materials
In this lesson we will use the following data that is provided as a GeoPackage from the main module page:
- subcatchment layer with polygons delineated from the DEM
- DEM raster derived from the SRTM 1-Arc Second product. Downloaded from USGS Earth Explorer and further processed in QGIS.
- CORINE 2018 Land Cover 100 m raster provided by Copernicus
- NDVI derived from a Sentinel 2 image of 7 May 2020. Downloaded from USGS Earth Explorer and further processed in QGIS.