Grid transformation issue; ESRI > Map3D

[ScotBIM]

Our client here in Saudi Arabia has provided us with an ESRI generated dataset of a proposed alignment – and although they have provided it in one zone, all our design work has to be done in another. However when I import the SHP file in Civil3D/Map3D the data is projected thousands of kilometres away.

The original .prj file shows that the data is in Lambert Conformal Conic projection for Asia, Meter (ASIA-LM-CONIC):

PROJCS["Asia_Lambert_Conformal_Conic",GEOGCS["GCS_Ain_el_Abd_1970",DATUM["D_Ain_el_Abd_1970",SPHEROID["International_1924",6378388.0,297.0]],PRIMEM["Greenwich",0.0],UNIT["Degree",0.0174532925199433]],PROJECTION["Lambert_Conformal_Conic"],PARAMETER["False_Easting",1000000.0],PARAMETER["False_Northing",3000000.0],PARAMETER["Central_Meridian",45.0],PARAMETER["Standard_Parallel_1",27.0],PARAMETER["Standard_Parallel_2",21.0],PARAMETER["Latitude_Of_Origin",24.0],UNIT["Meter",1.0]]

And I have to transform the associated .SHP file to UTM-WGS 1984 datum, Zone 39 North, Meter; Cent. Meridian 51d E (UTM84-39N) – however when I do this either, as a transformation when importing the SHP file or by attaching a drawing and running a query, the data is not projected in the eastern province of Saudi Arabia, but over 7,000,000 kilometres away in Kazakhstan(!!) . . 

I have been bragging that Ciivl3D can provide us with all the design tools we need, but I had to give it to our GIS department to transform in ESRI and produce a DXF of the alignment – not an elegant solution.

I can’t work out what I am doing wrong in MAP3D or if the algorithm for ASIA-LM-CONIC to UTM84-39N is correct. 

[antoniovinci]

Please zip and attach here the whole shapeset, sir.

[ScotBIM]

Antonio - aye, but there is the rub . . . . I would love to but our client is uber-cautious regarding security and sharing his data on a public forum is not going to happen. . .  Nevertheless I will see if I can source a sample file of nothing that is planned or existing.

I was hoping that maybees someone from Autodesk would look at the algorythm itself . .  

[antoniovinci]

I understand, so feel free to share with us only a draft boundary of that shape, as long as its .PRJ file.

[ericcollins6932]

Saudi is ~45° East longitude and so is the central meridian of the .prj file provided.

UTM39N has a central meridian of 51°

UTM38N has a central meridian of 45°

Methinks you are possibly using the wrong UTM zone?

[antoniovinci]

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ericcollins6932 wrote:
you are possibly using the wrong UTM zone?

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Well, the OP was talking about a 7k miles away error, so I guess it's not a "38-vs-39N" UTM issue.
Sounds like something went wrong upon the datum transformation, but I'd like to check those data out...

[phil_borycens]

WGS84 UTM zone 39N looks like a valid coordinate system for much of Saudi Arabia (at least for most of the eastern part of the country). Here is a screen capture of the zone from spatialreference.org:

On the AutoCAD Map side, the fastest, easiest way to check coordinate transformation algorithms is to:

1. in a new drawing, assign the source CS

2. open the Track Coordinates tool (MAPTRACKCS command) and add the destination CS

Now pan around in the drawing. Do coordinates appear in the tracker? If the coordinates are blank in the tracker, transformation is not occurring. If transformation is not occurring, we can help you investigate further -- as mentioned, it's easiest if we get a small sample but I do understand security concerns.

(Another tip for Track Coordinates is remember you can add several coordinate systems to the tool. Try adding LL84 to the tracker as well; this way you can observe the Lat/Long values of your cursor's current location and then enter them into another tool like Google Maps to verify its location.)

And, you probably know this already, but you should try specifying the source CS for your SHP data when bringing it in. I didn't catch how you were bringing the data in (MAPIMPORT or Data Connect), but in either case, you have that ability. This is important especially if AutoCAD Map sees your data as being in an 'unknown' spatial context.

[sushma]

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