Civil Engineering Transportation GIS Workshop
Lab Exercise: Geometric Calculation Differences
- Start ArcMap.
- Check data frame's coordinate system: within Table of Contents, double click Data Frame to open Data Frame Properties. Click Coordinate System tab - there is no coordinate system identified.
- Add data: ...MapProjections\DMTI_Roads_Calgary
- Check the layer's coordinate system: double click the data layer to open the Layer Properties. Click the Source tab - take note of the geographic coordinate system.
- Check data frame's coordinate system: the data frame adopted the coordinate system of the (first) added data layer.
- Select NAD_1983_UTM_Zone_11N as the projected coordinate system. To execute geometric calculations (e.g. shape length) a projection needs to be identified (in data frame or set as part of the data layer).
- Set Transformation:
- Convert from: GCS_WGS_1984
- Into: GCS_North_America_1983
- Using: WGS_1984_(ITRF00)_To_NAD_1983
- Add Field: Open Attribute Table of the data layer, from Table Options select Add Field (name - RoadLength, Type - Double).
- Run Calculate Geometry in the newly created field. Set Property - Length and select Use coordinate system of data frame.
- Compare fields the two length fields. If you want the geometry to persist as part of the data layer, run Project (Data Management) Tool.
- Last Updated: Feb 28, 2018 12:56 PM
- URL: https://library.ucalgary.ca/encigisworkshop
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