Practical Manual - Malareo

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Open the Attribute Table of the new dissolved layer. You will notice that it has been aggregated (condensed) to just the districts. Geoprocessing of Raster Data Quantum GIS also supports raster based analytical functions. These are Raster Based Terrain Analysis and Raster Calculator. In Raster Based Terrain Analysis there are 4 analytical functions: Slope, Aspect, Ruggedness and Total Curvature generators. We will concentrate on Slope and Aspect. Slope is the steepness, or gradient of a slope. It shows areas of steep and shallow gradient. Aspect is the direction that the slope is facing. Both of these functions rely on the map units being in meters, hence they require a projected coordinate system whose units are in meters. For this exercise the Cape/UTM Zone 36S projection will be used. The Raster Geoprocessing Tools are located in the Plugins Menu, under Raster Based Terrain Analysis. The Raster Based Terrain Analysis Window houses both the Slope and Aspect functions. QGIS for Malaria Page 52
Task 5: Slope Analysis Open a new QGIS project and add the layer called elevation_UTM. This is a DEM of eThekwini. Change the CRS of both the layer and the project to Cape/UTM Zone 36S. Zoom to the layer extent. Open the Properties menu of the layer and change the Color Map to Psuedocolor. This is in the Style Tab of the Properties window. This now symbolises the layer to show the altitude differences. Open the Raster Based Terrain Analysis window. Select Slope as the Analysis Select elevation_UTM as the input layer. Give the output a name and make sure to save in the correct folder. Select GeoTIFF as the output format. Check Add Result to Project Box Display the resulting image as a Psuedocolor map. The resulting image is a raster layer showing the slopes of the image. QGIS for Malaria Page 53
Page 1 and 2: Introduction to Geographic Informat
Page 3 and 4: occurrences you can gain a better u
Page 5 and 6: Once in the folder, using your mous
Page 7 and 8: Map Legend You now have 2 layers lo
Page 9 and 10: Select the Identify features tool a
Page 11 and 12: 30% release it and click on Apply a
Page 13 and 14: It is important to note that althou
Page 15 and 16: Open your Identify features and exa
Page 17 and 18: Acquiring Spatial Data There are nu
Page 19 and 20: This adds the shapefile to the lege
Page 21 and 22: You will be creating a layer using
Page 23 and 24: This opens a co-ordinate reference
Page 25 and 26: Next you will create a line layer (
Page 27 and 28: Continue digitising the other roads
Page 29 and 30: If you are interested in seeing the
Page 31 and 32: PROJECT COORDINATE REFERENCE SYSTEM
Page 33 and 34: Task 1: Changing the Default CRS in
Page 35 and 36: Practical 5 Tabular Data Queries Ou
Page 37 and 38: ecords. Switching and clearing yo
Page 39 and 40: Practical 6 Spatial Analysis Outlin
Page 41 and 42: Task 1: Open a new QGIS project. A
Page 43 and 44: In order to make measurements in un
Page 45 and 46: Now to measure along the length of
Page 47 and 48: Buffer and Dissolve Buffer: Often i
Page 49 and 50: Open the Attribute Table for the Pr
Page 51: The result window shows the number
Page 55 and 56: Active Layers in the TOC Mathematic
Page 57 and 58: In this practical you will undertak
Page 59 and 60: 1999 (which was year 1 of the 10 ye
Page 61 and 62: updated with percentages of prevale
Page 63 and 64: Click on Set to current extent Leav
Page 65 and 66: Practical 8 Summary Practical Outli

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