County Cadastral Mapping

Capture cadastral details

Background and Objectives

The client is a leading consulting engineering firm specializing in the land development, water and transportation markets and offers services in Water and Wastewater, Transportation, Land Development, Planning and Entitlements, Natural Resources, Surveying and Mapping, Geographic Information Systems, Program/Construction Management and Special District Financing to public and private sector clients.

The objective of this project was to capture the cadastral details in reference with the recorder map, assessor map, ownership details, subdivision overlay maps, GPS & BLM grid details.

Key Aspects of the project

• Drafting
  Capture the cadastral data such as Tract Boundaries, Lot Lines, Parcel Lines and Road Centerlines referring to the input maps.
• Edge Matching
  The individual maps were edge matched to form a seamless map data.
• Clean-up & Topology
  The map was cleaned for the topological errors and the polygonal topology was created. The topological data was attributed with all the required information.
• Quality Control
  A QC check is undertaken after the conversion process and the output was evaluated on the accuracy of drafting, featurization check and dimension accuracy.
  
  

Services Rendered and Methodology
The scope of work involved the following activities:

• Plotting and Pre-processing
  Recorder & Assessor maps received from client are in image format, which are plotted and
  checked for any discrepancies.
• Drafting
  Drafting is defined as the process of converting the raster to the vector format using drafting standards. Drafting is performed in AutoCAD Map.
• Clean-up & Polygon Creation
  Perform cleanup to correct the dangling errors, overshoots, undershoots and duplicates of all layers.
• Attribution
  Object data is attached to the respective cadastral features in AutoCAD map.
• Quality Control
  Processed data is checked via automated software routines to ensure a one-to-one correspondence between polygons and centroid. Errors are highlighted and corrected by the GIS data technician. The process is repeated until no errors are found.
• Edge Matching
  Edge matching is performed by pulling up the adjoining map & establishing the common boundary.
• Spatial Adjustment (Vector Geo-Referencing)
  Spatial adjustment will be carried out using “Transformation-Affine” (scaling, rotating & shifting) with reference to the GPS control points provided by client in ArcMAP software.
• Export CAD to GDB
  The collection of CAD Layers to convert to geo-database features, the new output geo-database where all the input CAD features are put along with the accompanying tables The spatial reference to be applied to the Output Staging Geo-database if it is provided by client.
  

Tools Used:

• MicroStationJ
• AutoCAD Map
• Arc MAP