AUTOCAD INTEGRATION
Problem
Computer aided design or CAD files can be used in geospatial analysis software packages such as ArcMap. Integrating these file types can enhance analysis and help to create shapefiles that would not otherwise be available. For this project, I must use the North Carolina State University Masterplan CAD dataset to create a geodatabase of campus buildings, facilities, and other features. This geodatabase must contain separate layers for streets, streams, sidewalks, lakes, buildings, and athletic fields, which consist of line data for the first three and polygon for the last three, respectively.
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Analysis Procedures
The data I used in this analysis included a CAD dataset of North Carolina State University campus and the surrounding area, as well as an orthophoto of the same area. I used ArcMap (version 10.5) to georeference the data using the orthophoto as a reference. I first had to define the projection for the orthophoto, which was North Carolina Stateplane NAD83 (US Feet). I then used the orthophoto to georeference the CAD data. I used the corners of distinct buildings on either side of campus as the reference points. Once I had successfully georeferenced the CAD data, I exported each of the necessary layers from the polyline data into its own shapefile using the Feature Class to Feature Class conversion tool. This resulted in six new layers made up of lines. The buildings, lakes, and athletic fields layers, however, needed to be in polygon format, so I used the Feature to Polygon tool to convert the polylines to polygons. I then used the streets, streams, and sidewalk line layers, and the buildings, lakes, and athletic fields polygon layers to create a new file geodatabase.
Figure 1. Diagram of methods.
Results
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Figure 2. CAD data before (left) and after (right) georeferencing.
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Figure 3. Original line shapefile compared with polygon shapefile. Some of the lines were not correctly exported into polygons, such as the large building on the lower right.
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Figure 4. Result of the Polyline to Polygon tool. All of the building polygons were present.
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Figure 5. All layers correctly georeferenced and displayed.
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Figure 6. Closer view of all layers within the main campus area.
Application & Reflection
I thought that this project was very interesting and provided a great “real-life” scenario to apply my GIS knowledge.
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Problem Description: NCSU is well known for the plethora of large trees, especially oaks, inhabiting the campus. These trees help to beautify the area and provide a number of ecological benefits; however, old trees are also prone to cause damage when limbs become weak and die. This could pose a hazard to campus facilities, especially buildings. This creates an opportunity for GIS analysis to help in management procedures.
Data Needed: To expand on this project, one could use the NCSU Masterplan CAD dataset in conjunction with a layer of tree data to determine the spatial distribution and conditions of different tree species. This could help the facility landscapers to determine if certain buildings have trees in poor condition nearby, and would help them to prioritize which trees to prune or replace when necessary.
Analysis Procedures: The first steps would be the same as those used in this project. One would first have to georeference the CAD data and create a polygon layer representing campus buildings. Then, one could open the trees layer and use the Select by Attribute tool to select only trees in poor condition. Lastly, one could create a buffer around campus buildings of roughly 5 to 10 meters. The landscapers could then target unhealthy trees that are within these buffers as trees in need of pruning and removal or replacement.