The Williamson CAD staff is responsible for the maintenance of parcel, abstract, school, municipal, subdivision, County, and MUD boundaries relating to over 155,000 parcels. They were faced with multiple challenges in this process, the first of which was maintaining cadastral data which was originally drawn without the aid of aerial photography, and did not spatially align with their orthophotography. WCAD was also faced with the problem of cadastral lines within their GIS that were not coincident.  In these cases, school district, abstract and additional cadastral lines did not align with the parcel boundaries they were intended to follow. Given the overall size of their jurisdiction, WCAD found the task of addressing these challenges to be daunting, and after considering available solutions, has again chosen The Sidwell Company as their professional GIS service provider. Under the most recent agreement, Sidwell will conflate the cadastral line feature class of the existing GIS.  Feature tags will be assigned so that, when queried, the selection set can be used to create topologically accurate polygons.  Sidwell will also register all cadastral boundary features in the GIS to the current digital orthophotography. According to Pamela Orr, WCAD’s Director of Operations, “Williamson Central Appraisal District chose The Sidwell Company for this GIS parcel rectification project due to their highly qualified and professional staff.” Orr adds, “Based on our prior experience with Sidwell, we appreciated getting a project that not only came in on time and under budget, but provided excellent customer service.”
 
Sidwell was previously selected by WCAD to convert their cadastral parcels from a MicroStation DGN format into the ESRI Geodatabase format, in addition to implementing their industry-acclaimed, ArcGIS®-compliant Parcel Builder™ software as a map maintenance solution.  This project, along with the Sidwell-developed public-access website which features the WCAD map data, and tabular data, was completed in late 2008. You can visit WCAD on the web at www.wcad.org.