GRW completed a comprehensive mapping and GIS project for Porter County in northwest Indiana. All products produced during the project were delivered in ESRI GeoDatabase format and in AutoCAD DWG format. The project was completed in three main phases:
- Photogrammetric Mapping
- Impervious Surface Mapping
- ArcGIS Server Website Design and Hosting
The Photogrammetric Mapping phase included new aerial photography, digital orthophotography, digital elevation modeling, and contours for all of Porter County (covering over 400 square miles of ground). Project specifications required that GRW generate a 1’ contour dataset for the overall project area from LiDAR data. To accomplish this part of the project, data was collected with an Optech 3100EA sensor at a 2-points-per-meter density. A bare ground surface was generated through the use of macro processing and manual editing. To supplement the LiDAR dataset, breakline data was added for hydrographic features and where additional elevation detail was required. GRW delivered final contour and DTM data in ESRI GeoDatabase and AutoCad formats. GRW also created grid files for the overall project area in AutoCad and ESRI formats. Grids were created for both the bare earth surface and the first-return dataset at a 5’ and a 25’ spacing. Once LiDAR processing was complete, the LiDAR surface was utilized as the elevation source for the generation of orthophotography. Color orthophotography was generated for the full county, plus a buffer of 1 mile. Orthophotos were generated to meet 1”= 100’ accuracy, with a 0.5’ pixel resolution, and was delivered in both GeoTIFF and MrSid formats.
The Impervious Surface Mapping phase included the mapping of all impervious surfaces for the major cities and towns within Porter County including Valparaiso, Portage, Chesterton, Porter, Burns Harbor and Ogden Dunes. Impervious surface mapping was delivered in ESRI GeoDatabase format. The impervious surface mapping was delivered in topologically structured closed polygons and included:
- Roads
- Bridges
- Buildings
- Paved Driveways
- Unpaved Driveways
- Paved Parking
- Unpaved Parking
- Patios
- Public Sidewalks
- Private Sidewalks
- Paved Recreation
- Airfield Pavement
The ArcGIS Server Website Development phase, resulted in the creation of public web site that hosted all of the GIS data that was created during the project. The website allows for the viewing of delivered contour data, grid data, DTM, orthophotography, and impervious surface layers in a web browser, without the need for additional software. The web site is accessible on-line here.