Pima County Geographic Information Systems

Parcel GIS Overlay Details

What are Parcel GIS Overlay Details?

Each parcel's information page on this website (like this one) has links that can gather over 100 parcel details based on how the parcel's location relates to other map layers such as zoning, city limits, school districts, and so-on.

This parcel process is an example of GIS overlay analysis. The details that parcel overlay analysis provides are "attributes" of the parcel that come from map layers such as Zoning, Jurisdictions, School Districts and many others. The information overlay details provide may not be available from other sources. It can also confirm or corroborate information from other sources and may be easier to find as well.

Parcel overlay analysis is a process that "looks" at GIS map data layers and determines how those layers relate to the parcel. For each area defined by a GIS map layer, parcel overlay details answer questions like:

• Is the parcel in or out of the area?
• Is the parcel partially in or out of the area?
• Is the parcel in more than one type of area?
• What is the area the parcel is in?
  • Zoning returns the parcel's zoning code.
  • Jurisdictions returns the parcel's city or other jurisdictional area.
  • School Districts returns the parcel's school district name.
  • There are over 100 more...

You do visual overlay analysis when you turn on a layer like Zoning using MapGuide and look at the displayed zoning areas on the map looking for the zoning code, if any, for your parcel of interest. You can have parcel GIS overlay details do this for you without using a map and without having to find, turn on, and interpret dozens of map layers that you may want to investigate for a parcel. (Depending on the overlay results you may still want to see the map layer on a map to get a better understanding of what the overlay process found.)

See What is GIS Overlay Analysis? for a slightly more technical overview.

Finding Parcel GIS Overlay Details for a parcel

Each parcel's "detail" information page on our website has an "Over 100 parcel details from GIS overlay analysis" section with links to groups of parcel details such as Census, Jurisdictions, Schools, etc. Together they display over 100 details derived from many overlaid GIS layers. The easiest ways to get to a parcel's detail information page are:

1. Use the "Search for a parcel" link toward the bottom of the main Pima County MapGuide Maps page. You don't even need to use a map.

2. If you're already in a MapGuide map, double-click on the parcel to open a new window with parcel information.

Sample Parcel GIS Overlay Details results

The diagrams below show sample Parcel GIS Overlay Details results. The corresponding map view is also shown to assist with understanding the result text. Parcel overlay details show only the text, not the map. However, the detail results page has a link you can use to go to the parcel's area on the Main MapGuide Map. You can then turn on the corresponding map layer that was overlaid with the parcel like these sample maps.

Parcel details that return just "In" or "Out":

The Rio Nuevo Business District layer has no identifying details that can be displayed. The result is simply whether the parcel is "In", "Out", or partially in the district. In this example, the large parcel near the center of the map is only partially in the district. This parcel is 4.29 acres. The overlay results indicate only 3.24 acres are in the district. The white triangular area of the parcel is outside of the district, making up the difference between the 3.24 acres that are in the district and the 4.29 acre total parcel area.

Parcel details that return values for each area:

The Riparian Habitat layer has areas coded "IRA, "H", "A", "B", "C", or "D". This sample area shows results with two of those coded values, "IRA" and "H". Results also include a field indicating ownership. In this example, the ownership values are all "PRIVATE RIP" which is short for "Private Riparian".