View Full Version : transverse mercator projection
2010-01-27, 12:18 AM
I'm using LDT2005 and would like to use Project>DrawingSetup>Zone>TransverseMercator
but I don't see it on the pick list. Does anyone know if it's available on a newer version?
"Transverse Mercator" is a type of projection, and is not a Coordinate System.
You should be selecting your desired Coordinate System in the zone. The type of projection is built-in to each Coordinate System definition.
2010-03-26, 04:19 PM
Not actually. While state plane grids are based on the transverse mercator grid system in some cases, he may be wishing to plot the actual UTM grid system which is based on Lat/Long like is showm on military maps and quad maps.This is the 100,000 meter grid system used by the military. My state is in Zone 16.
I'm not sure that any cad system can be set to that, but he could "fuge" the projection in by converting his points tp lat/long and applying the applicab le curvature factors to his line work. (That would be a pain!!)
State Plane grids are usually what is shown abnd as you stated, are built into the software.
The zone setting is in LDD2007, are you sure you have scrolled all the way to the bottom of the tab?
Not sure what you're saying Dent, but UTM uses a Transverse Mercator projection. (After all, that's what the "TM" in "UTM" stands for.)
And yes, UTM is built in to most systems. It's in Civil 3D and Map 2008 and later. Don't know about 2005 - that's too old, and I can't check. I'd be surprised if it's not there, however.
2010-04-08, 01:28 PM
Sinc, I am one of the few school trained cartographers that you will run across, so I am fully aware that "UTM" means Univeral Transverse Mercator.
The UTM coordinate system is what we used in the military to plot locations. The military does not use state plane coordinates bedcause they do not exist world wide.
Look on any USGS 15 minute Quad or 7.5 minute quad and you will see the UTM grid system. It is another coordinate system used on most maps.
If you have Corpscom, you will see that you can convert state plane coordinates to UTM values if you know the Zone for your area.
OK, as a school-trained cartographer, can you explain what you are saying?
UTM is a Transverse Mercator projection, just like any other Transverse Mercator projections. I have no idea what you are talking about when you say it is "based on Lat/Long". It is true that UTM is based on a datum, and that means we can convert between Lat/Long and our UTM coordinates. But that's all it means.
Similarly, the State Plane grids are based on datums, and use projections of various flavors. And similarly, we can convert between State Plane coordinates and Lat/Long, just as we can with a UTM systems. Some of the State Plane grids also use a Transverse Mercator projection. There is no difference between a State Plane grid that uses a Transverse Mercator projection, and a UTM zone, except for the parameters of the projections. A UTM zone is basically identical to a Transverse Mercator State Plane zone, except much larger (and with correspondingly greater error).
The OP was asking about selecting "Transverse Mercator" as a coordinate system. This is not a coordinate system, but a type of projection. It is possible that the OP wants a UTM zone, but that's an assumption.
Oh, and of course, even if we assume the OP wants a UTM zone, we still have a problem. We would need to know WHICH zone. But even more, we would also need to know WHICH DATUM.
I know that for us here locally, when we get stuff on UTM, it is generally either in UTM-27 or UTM-83. One is based on NAD27, the other on NAD83, and they are very different. The Lats/Longs are quite different between NAD27 and NAD83. Of course, data can be reprojected between the two datums, but it is critical that all the requisite metadata is known about the source coordinate system for the data.
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