AutoCAD Map 3D

[#1]

I made a big mistake when I did a converion on some drawings a long time ago. I thought the drawings where NAD 27 UTM 15 feet and I needed them converted to NAD 83 UTM 15 feet. Well, I found out that I was wrong and the drawing that I thought where NAD 27 where already NAD83. So I thought if I did a conversion from 83 back to 27 everything would be fine. WRONG. How do I go about fixing this?? I need help!

Thanks in advance.

Keith

[#2]

I hope I can help you here.

The absolute best way to fix your problem would be to get a backup of your file in the original zone.

ArcView may be able to help this problem. If you use 3.2 you will need the projector utility(not the one that ships with the program). If you use Arcview 8.1 it will reproject on the fly.

I don't know if or how you can modify the file with arcview.

Unfortunately AutoCAD Map's coordinate conversions are still a little dirty; I hope Autodesk gets the bugs out.

[#3]

Hi pmlhome,

I have to take exception to your comment that the Map conversion tools are "dirty" and the inference that there are bugs to be ironed out. Without getting into specifics, I can assure Map users that the coordinate system conversion tools are high quality, and that there are no bugs logged against the coordinate conversion tools. There are also features available in Map and other Autodesk products that are simply not supported in some other GIS and mapping applications.

If you have specific instances of problems that you think are present, I'd be interested to hear them.

Cheers,
David Walsh

[#4]

Hi Keith,

I tried this on a sample drawing the other day; I went from system A -> B and back to A again. The data seemed to transform just fine. What exactly are the problems that you found?

David Walsh

[#5]

in advance, i apologize for this question . . .

i have established a series of .dwg files w/ georeferenced data based on
nad83, central texas state plain, feet. everything comes in great. i know
have additional data assigned coordinates from usgs maps (still
texas-central) zone 14, coordinates are utm easting xxx,xxx & utm northing
x,xxx,xxx whereas my existing coordinates are x,xxx,xxx , xx,xxx,xxx. i've
tried assigning different coordinate systems to new drawings and bringing in
data again, but i still wind up with the x,xxx,xxx by xx,xxx,xxx
coordinates.

could someone please help out a gis-ignorant landscape architect?

thanks in advance . . .

Dan

[#6]

Sounds like you just have a units conversion problem if I understand correctly. Coordinates from USGS maps will be expressed in meters. You'll have to assign UTM Zone 14 meters to the USGS coordinate data and then query it into your drawing that it is UTM 14 Feet.

Ray Weiser

[#7]

I am converting a drawing from MO83-cf to NAD18-15f and getting double data
when the conversion if done. One appears to be a block of all the data and
the other appears to be the actual data. Anyone know why I'm getting double
info? I open the drawing and I have 1 set of data. Running Map 5 that come
packaged with LDD 3 on Win 98.

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