GRW was selected to provide comprehensive planimetric mapping and polygon services for Milwaukee County, Wisconsin. The planimetric mapping project covered approximately 250 square miles and contained a wide variety of features, including: buildings; roads; bridges; parking; driveways; sidewalks; vegetation; utility poles; hydrology; wall/fences; guard rails; and tanks/towers.
The features were mapped from recent digital orthophotography and LiDAR data. The orthophotography was used to digitize features on the ground such as roads, parking, driveways and sidewalks. The LiDAR data was used to digitize features with height such as buildings, bridges, and other overhead structures. Buildings, roads, bridges, driveways, parking areas, and sidewalks were digitized and delivered as topologically structured closed polygon features with no overlaps, gaps, or free end-points.
The final database was verified with 100 survey-grade GPS check points to confirm that the mapping met the accuracy requirements of the project. The project was completed in ArcGIS Version 10.x GeoDatabase format and was performed using ArcSDE disconnected editing so that multiple users could edit the database simultaneously, and so the client could check-in, review and use production areas as they were completed while other areas were still being edited.
Under a separate contract, GRW is providing polygon services for Milwaukee County.