Importing .dxf to Global Mapper

[GPSJane]

I am busy exporting .dxf  and .dwg files to Global Mapper but it says they don't have projection information. I have set the coordinate system and as part of that datum there is a description of what projection is used. Now I have to find the datum and projection and it is not that easy to get this right. Does anyone have experience exporting ACAD files for use in other GIS software? I would make life easier if the coordinate system I choose in ACAD could be read in the other woftware.

[antoniovinci]

Which CRS did you set in Autocad, before saving as DXF..?

[GPSJane]

Do you mean coordinate system? I am using Lo29 although I just tried WGS84 in case the coordinate system had to do with it and I had the same problem.

[antoniovinci]

Perhaps I've an idea: would you please copy-and-paste here the LO29 coordinates of a point somewhere in the center of the drawing..?

[GPSJane]

That took a while, sorry.

X = -10184.289 Y = 2306391.982

There is also an issue with the signs and the quadrant used by ACAD vs other software. Basically, though, this should work for a south-oriented Transverse Mercator projection and the Cape datum Lo29 (central meridian of 29°).

[parkr4st]

Usng Map3d 2015

I set crs to Lo29, entered the point and saved to dxf attached

opening it in a blank map and the file set the crs to Lo29 so that is in the file,  try it and let us know

I also map exported to shp and had to set  crs to LL84 to get the prj file to write

dave

[antoniovinci]

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GPSJane wrote:

X = -10184.289 Y = 2306391.982.

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Does that point refer to somewhere 12 km at north-east of Gwanda (Zimbabwe)..?

[GPSJane]

Dave, thanks for the confirmation that I am not being stupid. Global Mapper still can't read the coordinate system and I have to go select it myself. That is good to know about the .shp file as that does not help if we ever need to create shape files and send them to someone.

antoniovinci, yes, spot on. Zimbabwe is why we still work in Lo29 by the way

[antoniovinci]

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GPSJane wrote:
yes, spot on

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 When you load the DXF in GM, you should simply declare the EPSG:22289 as CRS.

[GPSJane]

Well I have to choose the datum and projection from drop down lists. When doing batches of multiples files this is frustrating. I will have to ask them to help me find out why the dxf coordinate system is not being read. When I have time!

[antoniovinci · Accepted solution]

With my 2006 release, I can set the current CRS by prompt, so maybe in yours too.

In the F2 window, paste the following string:

(ade_projsetwscode "RSA-LO29")

When you now run the ADESETCRDSYS command, it should be already filled by that LO29 code.

If it works,  create a new icon, and assign the string to it.

[GPSJane]

Oh cool, thanks. That is very helpful 🙂

I meant choosing the info from Global Mapper's interface although it was just as irritating doing it form the lists in ACAD. That makes it easy, I am even going to add it to my macros for setting standards in old files.

Now I just need to get GM to see the coordinate system so I don't have to do it twice...

[antoniovinci · Accepted solution]

GPSJane wrote:

Now I just need to get GM to see the coordinate system 

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I fear you won't do that, just because the CRS embedded in a DXF file is not "visible" out of Autocad Map (as far as I know).

I would try another approach, i.e. _MAPEXPORT all your LO29 maps to shape format, then GM should read the .PRJ file:

[GPSJane]

Aah, thanks. That explains it. So it's not Global Mapper. Why on earth does AD not make that information available? Aaargh!

I will look at exporting shape files instead. Thanks for the answer.

[GPSJane]

I feel I should know this but how do I create a button with this assigned to it? This is so much more helpful that the dialogue 🙂

[antoniovinci]

GPSJane wrote:

how do I create a button with this assigned to it?

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Sorry madame, I can do it in my archaic Map2006, whilst in newer releases.. wait for up-to-date other gurus' advices...

[parkr4st]

Button do do what exactly?  We have covered alot of items so need some refinement. 🙂

dave

[GPSJane]

Lol, good point:

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@antoniovinci wrote:

With my 2006 release, I can set the current CRS by prompt, so maybe in yours too.

In the F2 window, paste the following string:

(ade_projsetwscode "RSA-LO29")

When you now run the ADESETCRDSYS command, it should be already filled by that LO29 code.

If it works,  create a new icon, and assign the string to it.

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[antoniovinci]

Another way is to save the RSA-LO29 code in a .DWT template, then open the latter, and drag&drop any DXF inside it.

[GPSJane]

I just discovered that the ADESETCRDSYS command that you mentioned also allows me to batch apply to entire lists of files from multiple directories 🙂 Yay. Thanks so much.

Of course now I have to export everythign to a shape file for import to Global Mapper but I have to export the data for 3D modelling anyway.