6.9.1. Downloading data and changing projection
First, land cover data for the region surrounding Fribourg will be downloaded and extracted.
- Download the dataset g100_06.zip (CLC06 – 100 m) from the website http://www.eea.europa.eu/data-and-maps/data/corine-land-cover-2006-raster-2 to a local directory (e.g. on the Desktop).
- Unzip the file g100_06.zip with a file archiving program of your choice (if you need additional software for this task, the program “7-zip” is a good choice: www.7-zip.org) into your ArcGIS working directory (e.g. the GISBEEBOOK folder). Note: data in zipped folders cannot be seen in ArcGIS applications so you must first unzip.
- Open ArcCatalog.
- Navigate to folder containing the land cover raster g100_06.tif and select the Preview tab to get a visual impression of the data. As you can see, the data layer covers all of Europe.
open the Properties of the raster
layer by double-clicking the layer name.
From the General tab in the layer properties, you see that CLC06 is a 1 band raster dataset with 8 bit unsigned integer values (that correspond to different land cover categories) at 100 m horizontal resolution. Because it covers all Europe, the CLC06 raster is quite large and the rendering on the screen may take some time. We will improve the performance by clipping to the extent of interest. The coordinate system is different (ETRS89_ETRS_LAEA) than the one used in Switzerland therefore it is best to project it into the same coordinate reference system as the other layers (CH1903 LV03).
- Now, add the CLC06 layer into a new blank *.mxd by dragging the layer from ArcCatalog into ArcMap directly, or using the Add Data button in ArcMap.
- To reproject the raster to the Swiss coordinate system, open the Project Raster (Data Management) tool (browse to Data Management Tools > Projections and Transformations > Raster > Project Raster).
- Select g100_06.tif as the Input Raster. The Input Coordinate System will already be filled in.
- Save the Output Raster Dataset to your working folder as g100_06_ch1903.tif.
- Choose CH1903 LV03 as the Output Coordinate System (Projected Coordinate Systems > National Grids > Europe > CH1903 LV03).
- Choose the NEAREST Resampling Technique.
- Leave the default Output Cell Size (100 m) (Fig. 48).
- Click OK.
OK again to run the tool.
Be patient, this is a large file and it will take some time to complete (~ 10 minutes but depends on your processing system). You will get a pop-up at the bottom right-hand side of your screen when the process has finished.
The resulting projected raster (g100_06_ch1903.tif) will be automatically added to the *.mxd. The original CLC06 layer can now be removed from the document as it is no longer needed:
- Right-click the g100_06.tif layer in the TOC.
- Select remove.
Fig. 48. Project Raster dialog for the reprojection of the Corine land cover 2006 (CLC06) layer.