"Scaling about a point different that the SPCS origin?"
I've heard that Oregon is using some LDP's, otherwise every DOT I've been involved with (not all that many) do it the same way, coordinates multiplied from 0,0 by the combined factor.
Since so much data is produced that way from ROW maps, descriptions, section ties, really good ortho's,,,,,it's a good idea to learn how to use it. Regardless of how you feel about the process
"Scaling about a point different that the SPCS origin?"
> I've heard that Oregon is using some LDP's, otherwise every DOT I've been involved with (not all that many) do it the same way, coordinates multiplied from 0,0 by the combined factor.
>
Yep Oregon DOT is utilising Low Distortion Projections, LDP
http://www.oregon.gov/ODOT/hwy/geometronics/Pages/ocrs.aspx
Previously they like to see the Local Datum Plane LDP method used being scale coordinates at 0,0 by the csf.
http://www.oregon.gov/ODOT/HWY/GEOMETRONICS/docs/ldp_workshop/1_making_the_case_for_change-ron_singh.pdf
Probably could have used a different acronym for the current stuff but it is what it is.
"Scaling about a point different that the SPCS origin?"
I like using LDPs a lot, however other users don't like them at all:-(
"Scaling about a point different that the SPCS origin?"
I've heard that Oregon is using some LDP's, otherwise every DOT I've been involved with (not all that many) do it the same way, coordinates multiplied from 0,0 by the combined factor.
Just for the record Iowa DOT is going to 14 LDP zones this summer. Up to now they scaled about a central project point to facilitate imagery overlays. Scaling about 0,0 does not play well with imagery.