Hi, Fred. Funny that we're carrying on interoffice communication on a public listserver, but I'll reply here for completeness of the thread.
I think one of the experiements I've done over the past couple of days includes your procedure. 1. I saved the polygons from the NAD27 map into a .ply file, converted it to a .xyz file of lines, imported it into a new database, and attached appropriate NAD27 projection information to that (X,Y) pair. 2. I did a coordinate transformation of this (X,Y) pair to the WGS-version parameters producing a pair of channels named XW84 and YW84. 3. When I post either of these coordinate sets as lines, they post directly on top of each other even though the actual numbers in the channels are different by ~3 meters in the X coordinates and ~21 meters in the Y coordinates. >From this experiment, I infer that Oasis is handling things consistently internally. However, and here's the rub, when I post the original .ply file that I saved from the NAD27 map, the polygons appear ~215 meters north of those lines I posted from the database (how did we ever live without the Ruler feature?). Recall that this file has NAD27 projection information in header records that begin with /#. To see if these header records have some effect, I removed them from the .ply file and posted again. The polygons post in yet a 3rd position - very near those from the lines database. Any thoughts? Regards, DLH _______________________________________________________ More mailing list info http://www.geosoft.com/support/listserv/index.html
