US Survey Foot or International Foot
I am a big fan of reporting state plane coordinates of all relevant control and monuments on my surveys. I typically dimension on the grid also -but not always. I mostly work in central Indiana where there is little vertical relief and not much difference between grid and ground (a few hundredths to fifteen hundredths in a quarter mile). To me, for a modern survey, coordinates on a known datum are an important part of a survey as they are so easy to retrace. Its ok with me if this is not part of your approach.
I was recently asked why I still use US Survey Foot instead of international feet by a 20 something y/o. I answered because I am a 50 something y/o. I guess I really should switch over.
Who here still uses US Survey Foot and who uses international? Why? Just curious.
I use the Int'l Foot when working in NAD83 in Oregon. The "Oregon Coordinate System of 1983" is so defined in state law. The same law dictates using US Feet when working in NAD27, but I haven't done that in quite some time.
Similarly, Washington State statute law dictated the use of the US Foot - until recently. It was changed to the Int'l foot a couple years back in anticipation of the new NATRF2022 datum.
When the NATRF2022 datum is rolled out for real everybody everywhere will be obliged to use the Int'l foot.
Check out this document, which I found by googling "Indiana Coordinate System":
It's the law in my jurisdiction to use U.S. Survey Feet.
Oh, brother! Don't get me started on INDOT's low distortion projections. Went from Indiana's two zone SPC's (East and West) to 40-something separate projections. Unless they are working for INDOT, I don't know anybody using those LDP's. Even the county and city DOT's aren't using it.
Use the defined value for Indiana. If that's US feet don't change to international. It could be either a statute or basically an agreement with NGS.
Similarly, Washington State statute law dictated the use of the US Foot – until recently. It was changed to the Int’l foot a couple years back in anticipation of the new NATRF2022 datum.
When the NATRF2022 datum is rolled out for real everybody everywhere will be obliged to use the Int’l foot.
Washington's switch to international foot does not occur until the NATRF2022 datum is declared to be the NSRS. Do not use international foot in WA at this time.
https://www.dnr.wa.gov/publications/eng_plso_nsrs_meters_to_feet_with_nad83.pdf
Disclaimer:
The switch has already occurred, but trust me, it hasn't.
I would make a caveat to this: If there is a new realization that occurs between now and 2026 when the (2022) datum is put into effect, then it may be interpreted that we should be using the international foot.
We are in an interesting place when the PLSO, and the definition of WA North Zone, are calling for US Survey feet, but the code clearly says that the WPCS is Standard Foot.
Just another reason to NOT put coordinates on my maps. Maybe I will just report Cartesian Coordinates and a reference frame, eschewing any mention of WPCS or SPC.
The type of foot is as much part of the definition of a projection as the false northing and easting. If your SPC or LDP was defined with US Survey feet it makes no sense to try to use Ift, regardless of when or what some official body may say. That would be inventing a new map.
The change in type of foot comes with a new projection definition to go with the new datum.
The SPCs are all defined in meters (along with most published LDPs I'm familiar with). In most survey programs the units don't matter since they are just a matter of scale and be changed back and forth at the push of button. The one exception is AutoCAD which for some reason deals with units in the most backwards of ways.
Pretty sure most, I think it's 48 out of 50, state recognize us feet. I could be wrong on the recognition vs. usage.
I work in Oregon, so we all are pretty much on INT FT. Won't be long, based on NGS, that we ALL will be there.
Love reporting coords. Mainly on mons, but still great.
