Measured fer yer Chains...
Manipulations in ArcMap
Slope
As slope is based on elevation per unit distance, a 50 metre digital elevation model of the GVRD obtained from the S Drive was used to calculate slope. This file was already projected into the necessary coordinate system and so was simply opened in ArcMap and converted to ASCII format for importation into IDRISI where slope calculation was performed.
Landuse:
Upon opening the 2001 GVRD landuse file from the S Drive in ArcMap, it was decided that, since this file was already projected into NAD 1983 UTM zone 10N, this projected coordinate system would be used for all other layers created. It was then necessary to convert the shapefile into raster format. Rasterization was based on the landuse description field of the attribute table. This produced cell values of 1 to 17 representing the distinct descriptive classifications. A 50 metre resolution was used for rasterization as this conforms to the resolution of the digital elevation model. From raster format, the file was converted to ASCII format and imported into IDRISI for further preparation.
Population Density
The census analyzer was used to extract population values for dissemination areas in the GVRD. Tabular data was created in Microsoft Excel for use as a database file in ArcMap. A shapefile of dissemination areas in the GVRD was provided by Verda which had been obtained from data made available on the S Drive for Assignment 2 of Geography 351. This shapefile was projected into NAD 1983 UTM zone 10N. A join was created to add the data extracted from the census files to the attribute file of the dissemination areas shapefile. A new field was then added to the table and population density was calculated by dividing the 'area' field by the 'total population' field. The resulting file was converted to raster format based on the new 'population density' field created in the attribute table. A 50 metre resolution was used conforming to the resolution of the digital elevation model. The rasterized product was then converted to ASCII format and imported into IDRISI for further preparation.
Streets
The 'juststreets2' shapefile from the GVRD folder on the S Drive was opened in ArcMap. Projection was not necessary as this file was already projected in the NAD 1983 UTM zone 10N coordinate system used by the landuse file and the population density file. The projected shapefile was then converted to raster based on the 'street type' field with a 50 metre resolution. The raster output was then converted to ASCII format and imported into IDRISI for further preparation..