The Business Need
A Texas-based metro approached Mobius to provide PDF images and AutoCAD drawings to vector GIS conversion of water/sewer/storm network maps and associated attribute information into ESRI Data Model. The NCTCOG orthophotography, as a general reference, and GPS points, as spatial references were used to create the GIS layers. We were expected to create layers with parcel polygons, plot reclaimed water, all the hydrants, valves and storage facilities, the sewer systems and their flow directions, the location of manholes, and the storm sewers while including them with details such as flow directions, inlets, and outfalls.
Challenges we faced
Prior to the project proposals, all of the parcel polygons, water, sewer systems, and storm networks were stored in PDF and AutoCAD drawings. The project forms were pdfs that varied from 10 to 150 pages each, and also included AutoCAD drawing files that had to be digitized.
However, these challenges were overcome using tools such as Quantum GIS (QGIS) Open Source that was used to modify the polygons and points. Another ArcGIS licensed software was used for final validation checks such as Geometry checks, topological checks, etc.
How we solved the problem
Mobius took several steps to ensure efficient conversion of graphical legacy data to industry standard GIS format. Network assets were placed in relation to land base, base map, and other water/sewer/storm features as per the customer’s requirements and all network relationships were maintained.
We analyzed the input files and identified the list of feature classes (placements) to be captured from the source files. Mobius came up with a focussed approach in order to capture the water/sewer/storm network assets from scanned maps into data model defined by the customer (Exhibit A Data Dictionary).
Upon capturing the parcels, subdivisions, and easements by overlaying orthoimages and project plans. We also performed the Quality routine checks such as Topology and Network checks on the converted GIS database.
The captured parcels, water, sanitary sewer, storm, and easements were delivered to the customer in ESRI SHP/FGDB format as desired. Targeted collection efforts yielded outstanding results.