How To Import LINZ Elevation Data into IRRICAD (NZ)

Tutorials and 'How To' information.
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jovivier
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How To Import LINZ Elevation Data into IRRICAD (NZ)

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1. Visit the LINZ Data Service Website (http://data.linz.govt.nz/)
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2. To download data, you need to register with your email address. Registration is free. Register using the “Register” link in the top right-hand corner, above the map.
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3. Pan and zoom to your area of interest on the map.
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4. Turn on the elevations layers to include the data you want to export. The “NZ Topo 50 Data” layers offer the best resolution.
• In the left-hand list, click the “Elevation” link, under “NZ Topo 50 Data”
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• Click the “+Add” buttons to add the “NZ Mainland Contours” and “NZ Mainland Height Points” layers.
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5. You can now focus more tightly on specific map areas using the “Crop” tool.
• Click the “Crop” button at the bottom right of the left-hand panel.
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• Drag a box on the map to specify an area for data download.
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6. Click the green “Download or Order” button, next to the crop button (see step 5). Select the appropriate download format and map projection. It is highly recommended that you download in Shapefile format, using the WGS 84 / UTM Zone 59S (EPSG: 32759) projection if in the South Island. Note most of the North Island and eastern Marlborough is in UTM zone 60S. If you have data to import from other sources, ensure that that data uses the same projection.
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7. Click “Accept terms and create download” and wait for LINZ to create your dataset. If you have selected a large area this might take some time. LINZ can optionally e-mail you when your download is ready.

8. Download you data. The data set comes as a zip file containing a directory and shape file for each layer you selected. Save the zip file and extract it somewhere relevant – your Irricad “Designs” folder is a good choice.

9. Use “Import Contours” in Irricad to import the elevation data from the Shapefile(s). Note that this data is quite coarse, giving 20m contours. Once the data is imported, you can use “Interpolate Elevations” and “Calculate Contours” to add intermediate data if required.

10. Note that by adding extra layers on the LINZ website a wealth of other data – including map images, and some aerial photography - can be added, downloaded, and imported into Irricad in a similar fashion.
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