Hands-On Geospatial Analysis with R and QGIS

Sampling raster data using points

We can add values from a raster layer to a vector layer. Suppose we have a raster of digital elevation and we have point data in the same extent as covered by the raster. We can get the elevation data for the specific data points sampling raster data. In this case, we'll work with two files: dem_chittagong.tif inside the DEM folder, which contains the digital elevation data in southern parts of Bangladesh; and indicator.shp, which contains some point data (just longitude and latitude values), all of which are within the spatial extent of the raster layer. We want to extract the elevation data from dem_chittagong.tif for points in the indicator.shp shapefile. The steps to accomplish this are as follows: