GRASS-HRU/Tutorial

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Contents

Preface

Installation

Quickstart catchment

Catchment used in this Quickstart

Free sample input data

Datasets listed here are just samples to show the simple usage of GRASS-HRU and to provide you a quickstart. In order to improve the delineation results please consider to use more accurate data!

SRTM elevation

  • resolution: 90 meter
  • CRS: EPSG:4326 - WGS84

Go to http://srtm.csi.cgiar.org/SELECTION/inputCoord.asp, select and download the data tile for central/eastern Germany. Now cut the area of Thuringia using QGIS functions, e.g. Raster > Extraction > Clipper. Therefor, using the bounding box x1:9.861871, y1:51.703773, x2:12.677359, y2:50.176473 is an option. Finally, reprojct to a meter-based reference system - here we will use EPSG:32632 (WGS84/UTM zone 32N).

Corine Landcover

  • resolution: 100 meter
  • CRS: EPSG:3035 - ETRS89

Download the CLC 2006 - 100m dataset from http://www.eea.europa.eu/data-and-maps/data/corine-land-cover-2006-raster-2. The resulting GeoTiff file you can load into QGIS. Use Raster > Extraction > Clipper to cut in advance. Extent coordinates of x1:4311011.14124, y1:3172437.46652, x2:4508461.13837 and y2:3009522.44988 would be a good choice in order to keep the area of Thuringia. At the end, reproject to the target spatial refernce system (Raster > Projections > Warp) - in our case EPSG:32632 (WGS84/UTM zone 32N).

Result: tbd

Harmonized World Soil Database

  • resolution: ~ 1.000 meter
  • CRS: EPSG:4326 - WGS84

From http://webarchive.iiasa.ac.at/Research/LUC/External-World-soil-database/HTML/HWSD_Data.html download the zipped raster in ESRI BIL format (unzipped about 1.8GB!). As the format is supported by GDAL you can open it in QGIS and cut it afterwards (like landcover map above) - Pay attention to source projection (WGS84) when cutting and transforming the map extract (e.g. Thuringia again) to desired reference system and GeoTiff format.

HNZ Gauging stations

Search http://hnz.tlug-jena.de/aktuelle-situation/thueringen.html for gauging stations Rappelsdorf and Hinternah and create a simple text file that contains at least the station coordinates and a whole-number identfier. A header line is advised:

id, name, lat, long
42151, Rappelsdorf, 50.49646395, 10.72495857
42160, Hinternah, 50.51864038, 10.79306017

Using Layer > Add delimited text layer in QGIS, you can easily import the stations as a layer and convert it into a Shapefile as required by GRASS-HRU: Right-click on imported layer and save it to a new Shapefile. Do not forget to specify the desired target coordinate reference system, here EPSG:32632 (WGS84/UTM zone 32N).

Result: tbd

Results

HRUs of urban settlements with various threshold used for generalization

Nahetal-Waldau: Merging threshold: 5 cells
Nahetal-Waldau: Merging threshold: 10 cells
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