GIS Coverage Info and Status

Parcel Basemap Coverage Info and Status
"Uprooting your family and moving to a new city might be more fun than a tax audit but not by a wide margin. Think of the questions that flood your mind when you first find out you’re moving someplace new. What are the neighborhoods like? How far will I have to commute? Is there some place near by where we can go hiking? Where are the schools and are they any good?Pulling out a paper map might give you an answer to your commute question, but that’s about it. With a GIS map of the new town opened on your computer, you could get answers to all those questions. Answering questions is one of the things a GIS does best." Davis E. Davis

One of the ways Weber County GIS (Geographic Information Systems) is working to answer some of those questions is by creating a Parcel Map. A parcel map shows land ownership and descriptions of lots for everyone that lives in Weber County. This is used for property tax information but can also be connected to a myriad of data about the County and its residents.The Weber County parcel coverage was built using AutoCAD drawings made by the Weber County Recorders office. The creation involved a mosaic process of edge-matching all of the drawings for the entire county and then piecing these drawings together using section corner data supplied by the Weber County Surveyor. However, due to slight inaccuracies and rotational problems in the drawings, there were some complications edge-matching many of the pages. Some liberties were taken, so by no means is the parcel level base map of survey or engineering grade. Although, it is an accurate inventory of parcel level data for the county and it is adequate for answering a bulk of the County’s parcel level questions. Weber County will continue to advance the accuracy of the parcel map as more data becomes available. The base map was created is in State Plane, NAD83.

Information can be viewed on the GIS web page that allows anyone to view plots of land and get taxing, zoning and other land value information. Having the Parcel Map current is critical to keeping this information up to date on the web page. New subdivisions and property changes are added daily by the Recorders Office to the parcel map. They are continuing to use the same process of taking AutoCAD files and edge-matching them to the current map.Also, at the end of each year a parcel map will be date stamped and saved as the tax year map.

Centerline Coverage Info and Status:
"The movement of people, the transportation and distribution of goods and services, the delivery of resources and energy and the communication of information all occur through definable network systems." ESRI

Network systems are represented by line coverages in GIS, such as streets. By giving information to line data, like address ranges and street names, lines can be used as a tool to find spatial interaction of people and places. With such data EMS (Emergency Management Systems) can find the shortest or least-cost route to a series of locations. The best school bus route can be calculated, and fundamental address geocoding can connect all kinds of information with an address.

For example, if Mr. Weber lives at 1405 Play Street in Happyville and his house starts on fire, he of course contacts the Fire Department, who reside at 1600 W LampLight Lane. If the fire department or dispatch office has GIS they can enter that address and find the fastest way for the fire truck to get to Mr. Weber. They can also pull up information on where all of the fire hydrants are located around Mr. Weber’s house, and know if any power lines or other hazards surround his home. GIS can speed the process and answer questions before the fire fighters even arrive on the scene.

The centerline coverage (or digital street map) is crucial to a good GIS, and the creation of street data is priority one with Weber County. Of greater importance is having a geographically accurate database. To achieve the levels of accuracy we desired, the streets were generated from digitizing lines form georectified aerial images taken of the County in 1985. Of course that wasn’t the most current source available, so newer streets had to be drawn from 1993 and 1997 DOQ’s (Digital Ortho-Photo Quads). All streets that were created after 1997 have been added to the map using the Parcel Coverage. The hope for the future is to add streets using a newly acquired GPS (Global Position System) unit. This unit will help us to verify the geographic accuracy of the current streets and to get under 3 feet of accuracy on the new streets.

After all of the lines were drawn an attribute process began. About 30 fields of information were put to each line in the street coverage, the main ones showing street names and address ranges. The process was time consuming but the County felt that it was best to benefit the community by providing the most accurate information we could.The process has taken nearly 9 months to complete. It began Jan. 1, 2000 with a goal of completing it by the end of Sep. 2000, which we reached.The streets will be updated on a monthly basis, so that as we get this information open to the web it will be current.