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Phase 1: 2000 Aerial Photography Project (Status:100% Complete):

On March 17, 2000 Western Air Maps (WAM)  flew Vanderburgh County, Indiana. This produced black and white aerial negatives at a NCS appropriate for ASPRS Class 1 for    1-inch = 100-foot planimetric mapping and a two-foot contour interval. Aerial photography was exposed at 3960' +/- above mean terrain. This warranted a nominal negative scale of 1" = 660-foot and which produced 1-inch = 100-foot scale digital ortho images with a 6" pixel resolution. This means that each pixel within an image represents 6 inches on the ground.

Triangulation for control was accomplished by fully analytical methods. Positional accuracy (vector of both northing and easting coordinate errors) of pass points established by triangulation was sufficient to support digital photogrammetric feature accuracy requirements outlined by ASPRS Class 1 standards for a map scale of 1-inch = 100-feet. Planimetric mapping was also produced with ninety percent of all well-defined features (except control points) were positioned on the finished digital maps with an accuracy of at least +/- 2-feet of their true coordinate position, and such that none of the features shall be misplaced by a relative value of more than 4-feet. This also produced 2-foot contours with ninety percent of the elevation points determined from the contours having an accuracy of 1-foot or better with respect to true elevation, and spot elevation accuracy of 0.5-foot or better with respect to true elevation.

Phase 2: Vanderburgh County Parcel Conversion and Street Centerline Conflation Projects (Parcel Status:100% Complete; Street Centerline Status 100% Complete):

Parcel Project: Vanderburgh County encompasses about 77,613 parcels onto approximately 2750 paper maps of various scales and accuracies. During the 2001-2002 Parcel Conversion Project, these paper maps were converted into digital parcel lines that meet one-inch equals one hundred feet mapping scale which suggests an accuracy of +- 2ft. All horizontal coordinates are in survey feet in the Indiana State Plane Coordinate System (SPCS) West Zone (1302) North American Datum (NAD) 1983. Descriptive information about the parcels (attributes) are collected, entered, and maintained by each individual Township Assessor.

Street Centerline Project: During the 2000 Aerial Photography Project, over 13,000 street centerlines were captured at an accuracy of +/- 2-feet. These centerlines were highly accurate geographically, but did not contain street information like address ranges, street name, street type, etc. This information was contained in a national dataset like TIGER that was created by the Bureau of the Census. The problem with the TIGER dataset was that it was geographically off by hundreds of feet which is insufficient for critical applications like 911, Emergency Planning, Engineering, etc.

The first step in the project was to automate the process of transferring the street information (attributes) from TIGER to the highly accurate street centerline layer from the 2000 photography. This was done through a software process which tremendously reduced staff hours and achieved approximately a seventy to eighty percent success ratio. Currently this dataset is being thoroughly looked at (scrubbed) by Central Dispatch and will go through a series of tests to check its accuracies. After tests have been performed, this local dataset will be implemented into the new 911 system which brings several advantages for the residents of the City/County. Some of these include the following:

• Highly Accurate
• Maintained by local government departments.
• New streets are added quickly and by the departments that are responsible for address ranges.
• Once new streets have been added, the 911 system is updated right a way which would not be the situation with national datasets.

This dataset will also be the base in which Census boundaries like Tracts, and Blocks will be recreated to more accurately represent Evansville and Vanderburgh County. Once these additional layers are corrected, they will be re-submitted to the Bureau of the Census to be forever part of future Census releases.

Phase 3: Utility Infrastructure Project (Status: Beginning Stages):