topic Re: A CAD file (.dxf) doesn't project right. in Data Management Questions

A CAD file (.dxf) doesn't project right.

JonPeroff — Wed, 29 Nov 2017 12:45:07 GMT

A CAD file (.dxf) was sent to me and I extracted it to a geodatabase (in my projection) but it shows up 420 Km west of where it should. Is there a way to fix this? Anything I do to project it results in no change. I'm not sure what is going on.

Re: A CAD file (.dxf) doesn't project right.

Madanbhurati1 — Thu, 30 Nov 2017 03:34:43 GMT

There are two important things to know when we re-project, one you must know the input coordinate system in which it was drawn/designed and another is output projection. I assume that you should confirm your Input (CAD file) projection.

I would suggest to specify your input and target projection on your question. So one can understand the issue better.

If you don't know the input projection of your CAD file, you can go through following link to figure it out.

How To: Identify an unknown projected coordinate system using ArcMap

Re: A CAD file (.dxf) doesn't project right.

TieshengWu — Thu, 30 Nov 2017 09:13:26 GMT

Usually a cad file has a translation, rotation and/or scaling relative to original base map to make the sketch convenient for vision. Generally there is a cad layer labeling the original controlling coordinate points by which you can fix the projection.(this layer may be turned off in cad). Map provider should be consulted if no controlling points layer.

Re: A CAD file (.dxf) doesn't project right.

JonPeroff — Thu, 30 Nov 2017 22:20:15 GMT

Thanks for the suggestions. The original file is WGS 84 wkid 4326 authority EPSG. I need it in NAD 83 UTM zone 16N. I have tried to convert it to a coverage, geodatabase etc again but still no luck.

Re: A CAD file (.dxf) doesn't project right.

DanPatterson_Retired — Thu, 30 Nov 2017 23:47:47 GMT

do you mean it you can't convert it?

convert, Define (actual) Projection/coordinate system, then Project to the desired coordinate system would be the workflow

Re: A CAD file (.dxf) doesn't project right.

JonPeroff — Fri, 01 Dec 2017 00:06:47 GMT

That is correct.

Re: A CAD file (.dxf) doesn't project right.

DanPatterson_Retired — Fri, 01 Dec 2017 00:39:55 GMT

Not sure what 'that is correct' applies but

Cad to Geodatabase ... to convert the cad data

What are the values of the current coordinates in the cad file? are the X values in the range -180 to +180 and the Y's in the -90 to +90? If they aren't, then they aren't in Geographic coordinates and you may be using an arbitrary coordinate system etc.

Re: A CAD file (.dxf) doesn't project right.

JonPeroff — Fri, 01 Dec 2017 00:56:56 GMT

Sorry Dan. I did try to define projection and the results were the same as always (using different methods)

The Easterly Coordinate is in the 200000 and should be in the 540000 range

The northerly seems good.

Re: A CAD file (.dxf) doesn't project right.

DanPatterson_Retired — Fri, 01 Dec 2017 01:16:25 GMT

with those values, they could be in a variety of projected coordinate systems.

they certainly aren't in a geographic coordinate system and they certainly aren't in UTM zone 16N, unless you are 540 km from the equator...by chance did you drop a 0 in 540000 (ie should it be 5,400,000 and not 540,000). If you dropped a zero, then it could be in utm zone 16 BUT the question now becomes, are your units in feet or meters?

Re: A CAD file (.dxf) doesn't project right.

JonPeroff — Fri, 01 Dec 2017 13:17:17 GMT

Yes, you right it 5,400,000. I want to convert it to UTM zone 16 but when I define the projection it shows up it zone 15 and in meters.

Re: A CAD file (.dxf) doesn't project right.

DanPatterson_Retired — Fri, 01 Dec 2017 15:58:21 GMT

hence the question... UTMs can be in feet or meters... which is it? the difference would throw it off into another zone potentially.

You have to define it what it is, not what you want it to be, so if the units are meters, that is what you have to use from the appropriate options for UTM zone 16.

You aren't converting anything BTW, those coordinates are projected already, and have to be defined as such first.

Re: A CAD file (.dxf) doesn't project right.

JonPeroff — Fri, 01 Dec 2017 17:11:42 GMT

I'm not familiar enough with how CAD works or handles projections. I am not confident that it was properly provided to me in the manner I asked for. The best I can do is create a graphic from it, move it to where I need it and use it as a guide to create a new file. This is suitable for my needs. Thanks

Re: A CAD file (.dxf) doesn't project right.

RichardDaniels — Fri, 01 Dec 2017 17:35:24 GMT

Sounds like you are going to re-digitize the "graphic" and Create a new feature class? If you are giving up on defining your projection correctly then you should covert the DXF to a feature class then Georefernce the data in ArcMap instead. As a reference layer load a feature class that is in the projection that you want and contains lines or points that are shown in your CAD drawing. This could be a layer with Survey control points that are shown on your DXF or an airphoto of the area you are working with (e.g., has a road that is shown on your DXF).

See details at for georeferencing:

http://help.arcgis.com/en/arcgisdesktop/10.0/help/index.html#/Georeferencing_a_CAD_dataset/001000000010000000/

As a side note, at ArcGIS 10.5.1/10.4.1 they changed how what data is allowed in a project file (.prj). In the past you could include comments in your PRJ file. Now if you have comments the prj file will not be read by ArcMap. Check your .prj that came with your DXF and remove any comments.

Rich