Tutorial: Introduction to GDAL

1. Introduction

What is GDAL

GDAL is a translator library for raster geospatial data formats that is released under an X/MIT style Open Source license by the Open Source Geospatial Foundation. As a library, it presents a single abstract data model to the calling application for all supported formats. It also comes with a variety of useful commandline utilities for data translation and processing. See for more info: http://www.gdal.org

Learning objectives

After this course you will be able to:

Retrieve information from GIS data
Reproject GIS data
Change raster properties
Convert raster formats
Convert vector formats
Apply spatial queries on vectors
Convert comma separated values files
Perform batch conversion

Software

For these exercises GDAL needs to be installed, preferably using the OSGEO4W distribution package. If you have installed QGIS, the OSGeo4W distribution is already there. In the video you can see how to install the LTR version of QGIS, which we will also use later for PyQGIS.

Exercise data

The exercise data can be downloaded from the main page. It contains:

roads.shp: road map from OpenStreetMap (http://openstreetmap.org)

srtm_37_02.tif: tile of a Digital Elevation Model (DEM) from the Shuttle Radar Topography Mission (SRTM) (http://www2.jpl.nasa.gov/srtm/)

gem_2011_gn1.shp: borders of Dutch communities, freely available from CBS (Statistics Netherlands) and Kadaster (http://www.cbs.nl).

Locations.csv: table with object locations.

landuse.zip: contains land-use time series in IDRISI format.