Land use change and management
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4.1.Land use change and management Exercise02
- Bu sahifa navigatsiya:
- Install QGIS if you do not have in your system!
- Opening QGIS project
- Rasterize polygons into raster using attributes
- Rasterize points into raster using Grid interpolation method
- Inverse distance to a power
- Rasterize polylines into raster and reclassification
- Plugins Manage and Install Plugins…
- Raster
Geographical features presented in Figure 1. Delineation of the region based on landscape type and ranks for usability status exist in working directory of gisserver//GIS//CDB features called CentralAsia. Table 1. Alphabetic order of GIS layers in Central Asian feature
In this exercise, GIS base functions such as conversion tools of polygon to raster, polyline density, point density, Euclidean distance and weighted overlay which are able to run using QGIS will be used to evaluate land suitability assessment in Central Asia. Install QGIS if you do not have in your system! Press windows icon in keyboard and write cmd.exe and press ENTER, command line window will appear Use command line and write: cd gisserver/softs/gis/QGIS_R_installer/ and press ENTER Write a next line: install.bat and ENTER, it calls install.bat window for both R and QGIS installation: 1 – Install QGIS 2 – Install QGIS Plugins 3 – Install R-Packegts 0 – Exit Please write 1 to install QGIS and fallow to accept installing windows to complete installation Do the same and write 2 to install QGIS Plugins, fallow and complete installation Opening QGIS project Press windows icon in keyboard and write QGIS Desktop press enter to open project save project in the working directory D://CDB/CentralAsia/project folder write name as “rasterize” Rasterize_polygons_into_raster_using_attributes'>Rasterize polygons into raster using attributes Select D://CDB/CentralAsia/shape folder from Browser Panel and existing features appear Double click on Landscape.shp to enter layer into Layers Panel Rasterize vector data Click on Raster Conversion Rasterize (Vector to Raster). The tool dialog will appear. Set it up like this: Repeat steps from 3 to 5 in order to convert each features of “Land_Type”, “Relief” and “Rainfall” into raster module. Rasterize points into raster using Grid interpolation method Go to main menu and Click Raster Analysis Grid (Interpolation) Fill Grid (Interpolation) window as follow and click OK to finalize operation: Input file: click and dropdown Input file array select City shape file Mark Z field section and select ZPOP_THOUS field from attributes Mark algorithm section and select a method “Inverse distance to a power” In order to reclassify continues raster into discrete use Raster Calculator Look at the further steps through 18-19 and classify into 8 classes: (( "Popdensity@1" <= 10 ) * 1 + ( ( "Popdensity@1" >= 11 ) AND ( "Popdensity@1" <= 20 ) ) * 2 + ( ("Popdensity@1">= 21 ) AND ("Popdensity@1"<= 30 ) ) * 3 + ( ("Popdensity@1">= 31 ) AND ("Popdensity@1" <= 40 ) ) * 4 + ( ("Popdensity@1" >= 41 ) AND ("Popdensity@1"<= 50 ) ) * 5 + ( ("Popdensity@1">= 51 ) AND ("Popdensity@1" <= 60 ) ) * 6 + ( ("Popdensity@1">= 61 ) AND ("Popdensity@1" <= 90 ) ) * 7 + ("Popdensity@1" >= 91 ) * 8) Rasterize polylines into raster and reclassification Click VectorGeometry ToolsExtract nodes: in order to convert River networks as polylines into points extracting by nodes for further estimation of density. Dropdown Input layer section and select River shape file. Click Node’s section and select Create temporary layer Click Plugins Manage and Install Plugins… from main menu to activate required function for instance Heatmap Write Heatmap into search panel in Plugins window select Heatmap function and click Upgrade all button Note: Installed button provides you functions that installed plugins! Go to main menu and click Raster and select Heatmap Fill as follow the Heat Plugin window: Input point layer: select Nodes as temporary shape file of River network In the Output raster section select a path to the working directory where raster catalog located in CDB/CentralAsia/raster/ and write a name of new raster filename as RiverDens, respectively. In the Output format section select GeoTIFF In the Radius section write as 100 000 meaning we will suppose lands around 50 km radius potentially arable lands Click OK from plugin window when you fill all sections same as like instruction or below the picture. Click RasterRaster Calculator… Enter the expression as follow to reclassify River density continues raster into 8 classes: (( "RiverDens@1" <= 10 ) * 1 + ( ( "RiverDens@1" >= 11 ) AND ( "RiverDens@1" <= 30 ) ) * 2 + ( ( "RiverDens@1" >= 31 ) AND ( "RiverDens@1" <= 60 ) ) * 3 + ( ( "RiverDens@1" >= 61 ) AND ( "RiverDens@1" <= 90 ) ) * 4 + ( ( "RiverDens@1" >= 91 ) AND ( "RiverDens@1" <= 120 ) ) * 5 + ( ( "RiverDens@1" >= 121 ) AND ( "RiverDens@1" <= 150 ) ) * 6 + ( ( "RiverDens@1" >= 151 ) AND ( "RiverDens@1" <= 200 ) ) * 7 + ( "RiverDens@1" >= 201 ) * 8) Figure 1. Delineation of the region based on landscape type and ranks for usability status Click Processing and select Toolbox from main menu and Processing Toolbox will appear Write “density” into the searching section of Processing Toolbox in order to find a density extention Double click on Kernel density estimation from SAGA geoalgorithms Raster Creation Tools section Table 2
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