Land Layers

[john.guess]

I was wondering if anyone could point me into the right direction of finding any Sec-Township-Range layers for Oklahoma. For some reason when the database I'm working in was created, they only brought in enough Township/Ranges to cover the area that they were interested in originally and now we have stepped outside the box, and do not have the Township/Range layers that cover the new areas of interest.

[Kent Williamson]

John,

IHS offers land grid - here's the link on our website:

http://energy.ihs.com/products/lat-long

Best Regards,
Kent

[Kent Williamson]

I forgot to mention you can use PETRA Direct Connect to directly download the IHS land grid (if you subscribe to it) into your PETRA project using the shapefile importer found in PETRA Map at Overlay>Import Shapefiles.

[Clay Stringer]

Try this out:

The Land Survey Information System or LSIS is the official government Web site for the distribution of the Public Land Survey System (PLSS) of the United States. The Bureau of Land Management (BLM) cadastral survey program is responsible for the official boundary surveys for all federal agencies in the U.S. that together manage over 700 million acres. The Public Land Survey System also called the Rectangular Survey System is the foundation for many survey-based land information systems.

http://www.geocommunicator.gov/geocomm/lsis_home/home/index.shtm

http://www.geocommunicator.gov/LSIS6/map.jsp

Free PLSS shapefile downloads provided by the government.

Kent, is this the source IHS uses or do you have some proprietary data that's been through a better QC process?

[Kent Williamson]

Clay,

Ours is the Whitestar landgrid with proprietary IHS improvements.

Kent

[Bob Meyer]

John:

Just a reminder to make sure your well data locations and your land grid are all based on the same reference. The differences between NAD27 and NAD83 locations can vary by a few hundred feet in places. Sometimes that variance is not obvious, but you can have a big mess if your wells and landgrids are not consistent.

Bob

[Clay Stringer]

Clay,

Ours is the Whitestar landgrid with proprietary IHS improvements.

Kent

"WhiteStar’s Public Land Survey is digitized from USGS 1:24,000 series topographic maps using a highly accurate spatial averaging digitizing technique, which captures corner boundaries to +/- 40 foot accuracies."

Not sure how the BLM goes about getting its data.

Can you say what proprietary improvements IHS makes?


Also about NAD 27 vs NAD 83.  Don't be too quick to switch everything over.  Yes, multiple data sets need to be in the same system, or everything will be in the wrong place.  but there is no true mathematical conversion from 27 to 83.  There are mathematical estimations that get you close, but no true conversion.  I would pick the projection that has the most data and stick with that so you are converting as little as possible. 

That's why here in Texas the Rail Road commission still does everything in NAD-27.

[Kent Williamson]

Here is what our product manager for the IHS Grid LL told me:

In Texas, many of the enhancements have been to add Abstract Numbers to the grid where they did not exist.  There have also been some survey line movements.

In CA, we added grid from the CA Division of Oil and Gas that is not available in the PLSS grid that covers Spanish Land Grants.

In CO, WY, and NM we added BLM section layers.

[Bake7734]

In 2007 the Onshore Oil and Gas Order #1 was declared by the Department of the Interior, but hasn't been followed fully yet. Soon, to drill on federal lands you will need to use the geographic coordinate database system or PLSS GCDB (BLM grid). You won't be able to get an APD without using the correct grid and geodatabases. It is in everyone's best interest to take preemptive steps in being ready for the eventual enforcement of the order.

As to the grid data derived from the topographic maps; it is grossly inaccurate due to a majority of the lands being resurveyed over the last 20 years. You have to remember that topographic maps haven't been updated in 10-20 years. An oil and gas company can find its self drilling in the wrong location, because some sections have been adjusted 1000' or more. This can easily land you in the wrong section or quarter.

NAD27 to NAD83 - The conversions are easily done using ArcGIS, Corpscon, or any of the other datum/projection conversion tools out there. For the most part a conversion will have minimal distortion. Modern geodetics are excellent and the conversions are very reliable when using reputable software for the conversion.


Below are the links to the new rules.

Nifty website describing the order - http://www.ntc.blm.gov/krc/uploads/190/OnShore.swf
The order - http://www.blm.gov/pgdata/etc/medialib/blm/wo/MINERALS__REALTY__AND_RESOURCE_PROTECTION_/energy/onshore_order_videos.Par.62610.File.dat/Onshore_Order_No_1_The_Order.pdf

BAKE7734
GIS GUY
Oklahoma

[Clay Stringer]

NAD27 to NAD83 - The conversions are easily done using ArcGIS, Corpscon, or any of the other datum/projection conversion tools out there. For the most part a conversion will have minimal distortion. Modern geodetics are excellent and the conversions are very reliable when using reputable software for the conversion.

Yes, they are easily done with the software you mentioned, and for the most part, for oil and gas application, you won't have many problems.  I was just pointing out even NADCON (the federally approved method for transforming between 27, 83, 83 HPGN/HARN is an ESTIMATION only.

When you convert from say, a state plane to a UTM there are precise exact mathematical conversions, converting from projection to projection, there is a formula, plug in the coords and solve and you have your converted coord.  But Datum to Datum is totally different, your not just changing the way the coords are represented (projected) but your shifting the entire reference points and ellipsoid models used to derive those coords, it can only be estimated.


http://www.ngs.noaa.gov/TOOLS/Nadcon/Nadcon.shtml

The accuracy of transformations between NAD 27 and NAD 83 (1986) are typically 12-18 cm and 5-6 cm between NAD 83 (1986) and HPGN.

NADCON was developed in order to facilitate conversion between the datums,. The grids used by the program are based on more than 150,000 horizontal control points whose coordinates reside in NGS' data base, and provide transformed positions based on the shifts of the control nearest to the input position.

For the most part, in oil and gas 12 cm isn't that big a deal, for a surveyor that could be a big deal.  Plus the further your point is away from one of the 150,000 control points, theoretically the larger error you will have in the conversion.  So, because of that fact, just to be on the safe side, I always stick with the datum I have the most data in, so I convert as little as possible.  I have no problem converting projections in the same datum, that's just simple (not that simple) math.  But I convert datums as little as possible.  That's just my personal preference.

This mathematical estimation and resulting error (I think) is one of the reasons why the Rail Road Commission in Texas sticks with NAD27.

[Clay Stringer]

I stumbled across this today, more info on how whitestar created its land grid data set for Texas:





Beyond Spaghetti: Polygonizing the Texas Railroad Commission Digital Land Base

http://proceedings.esri.com/library/userconf/proc97/proc97/to150/pap102/p102.htm

[John Preston]

Another excellent source for Land Grids, and other GIS data, is Topographic Engineering in Oklahoma City. They have been my preferred vendor for GIS data in the Mid-Continent for many years. Here is a link to the map data portion of their site: https://www.topographic.com/datasamples.htm#landgrid

[Scott-Chaparral]

Then there is always Tobin landgrid, which my sales rep states is orthographically corrected from proprietary ortho aerial photography and legal description investigation. $$$$$
they also provide surface ownership lines and culture data that is far more detailed than you will find at IHS, Whitestar, TMC, or any others I have found... also very $$$$$

It just depends on what you are looking for and willing to pay.

[ShammWow]

I have created a new project and imported Whitestar data into various layers. For example layer 6 is townships and layer 7 is sections. When I try to use the "auto qtr. sec. grid" tool, I get an error of "Unable To Auto Detect Section Corners". What did I forget to do?

[Steve Hartzell]

Your sections were imported as a set of intersecting lines.  The autodetect only works if the sections are closed polygons.  You can manually pick the section corners with Tools>Qtr Section grid>Pick Section corners.  Alt-P is a shortcut.  Use F2 to snap to the corner, hit enter, and pick the corners.