Oblique Mercator

I'm a fan of the projection. It is simple to implement and an elegant solution, esp. when working with local mine grids. I was introduced to it many years ago by a gent who used to work for Mr. Potterfield. As I recall, Mike wrote the routine for the yellow-box equipment. It greatly simplified retracing prior work where the basis of bearing was assumed.

I prefer knowing what is going on rather than blindly accepting a black box site calibration. I may use it for a large triangulation network that I am currently retracing. The network is the Central City Triangulation Survey of 1880, which has over 80 triangulation stations. Most are drill steel holes with lead plugs, but about a 1/4 of the stations are building corners.

Like most things, it depends on the application.

Loyal, post: 333201, member: 228 wrote: I was wondering how many folks have used Un-rectified Oblique Mercator (Hotine) Projections in their work?

I know that Leon uses them on a regular basis, and I have used them a handful of times for specific scenarios where nothing else seems to "fit" the bill (so to speak). Shawn Billings and I have discussed their use a few times, and Cliff Wilkie and I recently discussed their potential use in RTK "Calibration/Localization" solutions. If I recall correctly, Mike Potterfield is a fan of this projection as well.

Aside from Alaska SPC Zone 1 (which uses a rectified version), and the US Lake Surveys of the Great Lakes, one does not encounter this projection (rectified or otherwise) very often.

I believe that it is a very elegant (and mathematically rigorous) solution to many of the extant (existing) "coordinate system" issues that many of us encounter. It is certainly superior to the multistep "scale, rotate" methodology all too often seen in "site calibrations" by some RTK Software.

Loyal

Loyal, I've been having so many problems merging coordinate systems with all the vendors.

I started doing my own thing back in the 90's because it produced "better" field numbers to do say a LDP of my own.

Problem was many clients and others couldn't use it.

They didn't have any programs or ways to create or access a projection outside the UTM, State plane universe.

For strictly in house work, fine, but for sending data to clients, others, not so good............

Of course you can always reproject the underlying data, but is it worth it to keep doing that?

I've looked at them (Oblique Mercator (Hotine) Projections), it's been my conclusion that I can do a LDP in say autocad, but only a Transverse Mercator one, I can't make a Lambert work outside of the existing state plane Lamberts already imbedded, maybe codes could be rewritten, but why bother.

Although, I haven't looked at the latest autocad version, the last time I beat my head against it was spring 2014.

And, of course calibrations are an abomination.