Description of the Problem
Computer Aided Design (CAD) data is not stored in the exact same manner that GIS data is stored and therefore requires some consideration when integrating CAD datasets into a GIS environment. In some cases this means that CAD data needs to be georeferenced and, when pulling data from CAD data sets, verified. The study presented here looks at the buildings in and around the North Carolina State University environs to understand the growth and development of the area.
Strategies of Solving the Problem
The problem was approached by acquiring relevant data from North Carolina State University which included CAD and raster orthographic data. The CAD data was then georeferenced to the raster orthographic data and necessary polyline and polygon data were extracted from the CAD into a file geodatabase.
North Carolina State University environs data was acquired from the University. The raster orthographic and CAD data were loaded into the GIS. The CAD data was then georeferenced to the raster orthographic data. Athletic fields, Buildings, Lakes and Ponds, Sidewalks, Streams and Creeks, and Streets layer files were written out from the CAD data into the file geodatabase as feature classes. However, not all of the buildings were represented as polygons when loaded into the GIS so the polyline buildings had to be converted to polygons using the Feature to Polygon Tool.
Discussion of Methods
There were a few issues that were encountered while working with the data mainly due to SQL queries. After understanding the issues that were being encountered with the SQL queries, there were no further problems.
Data Evaluation Procedure
Data was checked by looking at inconsistences in displayed data between raster orthographic and CAD data and then again with polyline and polygon data. It was further evaluated by measuring between points in the raster orthographic data and CAD data.
Reflection and Ideas of Other Applications
The integration of CAD data into a GIS has many applications not least of which has allowed archaeological researchers to display their results in a greater context as in displaying excavations within their greater environs. Some archaeologists have even gone so far as to suggest that CAD will allow archaeologists to depict their projects in a 3D format in GIS, however this has not yet been adequately demonstrated.