When Squares Aren’t Enough: Mapping Lots, Tracts, and Quarter-Quarters
Eyes often glaze over when I mention our “Lots, Tracts and Quarter Quarter” data. While customers are often familiar with the one square mile (640 acre) sections contained within a thirty six square mile township, many are often unfamiliar with the smaller section divisions, particularly government lots and tracts.
Mapping a land parcel or oil and gas legal description (the survey system used in thirty states) presumes familiarity with section subdivisions. Most commonly, this is simply a “quarter” (160 acres) or a “quarter of a quarter” (40 acres) or even a “quarter quarter quarter” (10 acres) of a section. Completely quartering a section assumes that it is a perfect one square mile.
Unfortunately in many cases, because of rivers, old Indian boundary lines, rough terrain, or other circumstances, a section deviates from the ideal. When subdividing a section, the federal surveyor wants to preserve as many ideally sized pieces as possible and create government lots to store the excess or deficient acreages. Here is an example of one such section abutting a lake.
In this example, the NW quarter and the SW quarter are idealized 160 acre subdivisions. What would otherwise be the NE and SE quarters are bounded by a shoreline, so the land is divided instead into numbered lots (Note: In some areas, the lots can also have letter designations.) A land legal description in this section might read: SEC 15 LOTS 1-2; NW meaning that the parcel covers all of the NW quarter as well as lots 1 and 2 of section 15 (160 + 48.92 + 31.23 or 240.15 total acres). There is no way to know where lots 1 and 2 are, or what geometries they have (in spite of absurd hard coded defaults in some software programs to the contrary) without a map.
Hand mapping land legal description is time and labor intensive, on the order of $75-$100 per hour. Someone could spend hours just researching and digitizing the example above, or they could do it automatically using software such as the WhiteStar Legal Mapper which references this type of data when it computes the land polygon. You can see that such workflow improvements can have a huge impact on the size and cost of a job when many legal descriptions must be calculated.
Clicking on our StoryMap, the states in red shows the states for which we have completed data. We have intentionally completed states with original data for which no alternative exists. In California, Colorado, Utah and New Mexico, we have curated and vastly improved the underlying data previously available. In addition we have integrated the best available sources and quality checked attributes as well as performed edge matching to all adjacent states. Finally, we make sure county boundaries coincide with section lines where they should.
Use Case: Weyerhaeuser
See how accurate Lots, Tracts and, Quarter-Quarters, data drove huge efficiency gains at Weyerhaeuser.
“About 80 to 85% of our legal ownership can now be automatically mapped in seconds”
