Please indicate any States that have implemented a statewide system of LDP's (Low Distortion Projections).
I want to help insure that these projections are added as standard projections in the Javad Coordinate System library. I'm sure other vendors will also want to make sure that their software includes these projections.
Oregon. https://www.oregon.gov/ODOT/HWY/GEOMETRONICS/Pages/ocrs.aspx
One thing the dot did a great job with in Oregon along with a free realtime network. Jp
Iowa Regional Coordinate System_IaRCS
Click on region of interest for PDF zone map and ESRI .prj links.
EPSG Registry codes EPSG::7057 to EPSG::7070
Oregon's doesn't cover the entire state, just the major highways.
County-based
Minnesota
Wisconsin
Indiana
Iowa (Not sure if this covers the entire state)
Tribal
US Rocky Mountains Tribal Lands (Montana, Wyoming)
I know of a few city/county-based ones too: San Francisco, Idaho's Ada county
Information on all these except Ada County are in the EPSG Geodetic Parameter Registry.*
You can tell them to check spatialreferences.org but it's not actively curated so there are lots of duplicates, etc.
* Disclosure: I'm on the subcommittee that maintains it.
In Minnesota each county has its own coordinate system. It was created and is maintained by MNDoT as far as I know.
The city and county of Denver uses one, the DIA (airport) has another, but I don't think it's state-wide.
mkennedy, post: 374290, member: 7183 wrote: Oregon's doesn't cover the entire state, just the major highways.
Oregon's doesn't cover the entire state, just the parts with people living in it.
I hear that they love them in Austin. 😀
Indiana is switching to a county system similar to MN from what I have been told.
Atlanta airport (HJAIA) has one. If I remember correctly, we have to figure out a GIS-friendly definition for the :stakeout:-designed "local" system.
Oh. Did I say that out loud? :-$
mkennedy, post: 374290, member: 7183 wrote:
Iowa (Not sure if this covers the entire state)
Yes it does, using 14 zones.
That Iowa report is really nice.
http://www.sco.wisc.edu/coordinate-reference-systems/coordinate-reference-systems.html
Here is the link for Wisconsin.
It is my understanding there is an LDP in San Francisco City/County.
After giving Low Distortion Projections some thought, reading Shawn Billings' two part article a while back, I do not understand the purpose or gain realized by creating a LDP. Grid is always grid.
What am I missing?
DWoolley
DWoolley, post: 374785, member: 6749 wrote: It is my understanding there is an LDP in San Francisco City/County.
After giving Low Distortion Projections some thought, reading Shawn Billings' two part article a while back, I do not understand the purpose or gain realized by creating a LDP. Grid is always grid.
What am I missing?
DWoolley
The datum surface may not correspond well with the terrain surface in a location (AKA grid versus ground). An LDP tries to move the projection surface closer to the datum surface via careful choice of parameters, including a scale factor.
