AutoCAD Integration

Development of Geodatabase of NCSU buildings and other facilities

Problem Statement

NC State University has AutoCAD data which was not georeferenced. However, it needed to use this data to develop a geodatabase for all its buildings and other facilities to inform its future projects. The objective of this assignment is therefore to use the Orthophoto layer in georeferencing the AutoCAD data, and then create geodatabase based on features in the layer.

Analysis procedure

To address the problem, I used virtual computing lab’s ERIS ArcGIS Pro 2.9.1 which is hosted on Remote Desktop Web Client. Main tools used were Define Projection, Move to Display, Move, Scale, and Add Points, to have the AutoCAD data georeferenced. I then used Feature class to Feature class tool, and Feature to Polygon tool to export the features to the created geodatabase. Data used was the one provided by instructor, which were the NC orthophoto layer, and the NC building AutoCAD data.

Firstly, I georeferenced the NC State Masterplan - 2005 CAD drawing file using the orthophoto raster layer which was provided. To do this, I added the NC orthophoto raster layer to the map and assigned to it the spatial reference which was in NAD 1983 (NSRS 2007) US feet projection, namely NAD_1983_NSRS2007_StatePlane_North_Carolina_FIPS_3200_Ft_US. This was done using a define projection tool which was found under Geoprocessing tab. After reviewing the projection system of the map, it was realized that it was projected on WGS 1984 Web Mercator. This was changed to the Orthophoto’s projection system for consistence on projection used to display data on the map.

I added the NC State Masterplan - 2005 CAD drawing layer to the map, which was displayed in Alabama, away from the required position since it was not yet georeferenced. I zoomed to the Orthophoto layer, and then selected the three layers under the AutoCAD data and clicked move to display under geofencing tab of the CAD layer manage tab. This repositioned the AutoCAD data but did not perfectly align it to the orthophoto extent. I used the move button to drag the AutoCAD group layer to the required position. Then, I used Add Control Points Tool, which was found under Adjust group, within Georeferencing ribbon tab, to select two sets of control points, starting from the point on the AutoCAD layer, and finishing with a reference point on the orthophoto. After this, I applied the adjustments, which repositioned the map to a closer alignment to the orthophoto. This concluded the georeferencing of the AutoCAD data. I then saved the world file through the georeferencing ribbon tab with a file name of NCST_Masterplan05_edited2.wld3.

In part 2, I started with coping the AutoCAD geodatabase to create a new file geodatabase of the masterplan. Copying was opted for since I did not want to lose the schema and the spatial reference which was already under the AutoCAD geodatabase. CAD was used to Geodatabase to convert the edited masterplan created above into feature layers under the new geodatabase. This did not produce the results I was looking for but exported the data as a group. Then I used feature class to feature class tool under the geoprocessing tab to export the following features into the geodatabase: 1) Streets, 2) Lakes, 3) Sidewalks, 4) Streams, and 5) Athletic Fields. For the building layer, since it was combining multiple layers, some of which were polylines, I used Feature to Polygon tool.

Process Diagram

Results

Application and Reflection

Problem Description: USAID Malawi has its school building project data in AutoCAD format. It would want to map this data in relation to existing schools in Lilongwe city. This would inform future plans and form a basis for justification with the Malawi Parliament on where to concentrate next based on the gaps that exists in secondary school facilities in Lilongwe City, Malawi.

Data needed: AutoCAD school building data, existing schools layer data, raster layer image of Lilongwe City, primary schools layer (as a proxy to populations with potential secondary school candidates). The data will be obtained from USAID/Malawi GIS database.

Analysis procedures: Now I will use the skill to georeference AutoCAD data from our school building project, championed by engineering team. I will first access the raster data layer from either landsat8 or sentinel image. I will classify the layer for visual contrast and assign a spatial reference to it. Thereafter, I will use it to georeference my AutoCAD data and save the features to the geodatabase through feature to polygon, since the buildings are a polygon. Then I will display this data together with existing building layers, and primary schools layer to showcase the gaps that exists in secondary school facilities within the five kilometer buffer of the primary schools.