Alberta 3TM vs 10TM projections

[Anonymous]

Hi:

I'm hoping someone can help me out.  I have data from Alberta I'm trying to work with.  Some of the data – the topo-  is in one coordinate system (NAD83, 3TM, 111W – a projection which covers a relatively thin slice of the province) while my property data is in NAD83, 10TM 115W (a projection that covers the entire province).  Using Civil3D, I've created drawings of both data and set the coordinate projections correctly for each from Map's coordinate system library.  When I try to bring one into the other using the Map Attach feature – the topo data appears to be in the correct place, but the property data is off by 50 kms or so north-south and by 8 to 10kms east-west. Any thoughts or advice would be appreciated.

I'm hoping someone in alberta using either Map or Civil3D would have run across this previously.

Thanks

[fieldguy]

Have you tried a query to transform from coord system to coord system?

http://docs.autodesk.com/MAP/2010/ENU/AutoCAD%20Map%203D%202010%20User%20Documentation/HTML%20Help/i...

[Anonymous]

Hi Fieldguy:

Yes thanks ...  i've tried that.  I've tried assigning the property data file with no coordinate system and assigning one through the query file settings.  I've tried assigning a coordinate system to the property data beforehand and attaching it, with the same results.  I've tried importing the map from .dgn with no coordinate system and setting it on the import, with the same results.  I've tied several different coordinate systems and datums, with the same or similar results.

I'm sure this issue crops up with folks doing work in rural areas in Alberta, but unfiortunately I don't know anyone there to check with.

[Sinc]

---

@Anonymous wrote:

Hi Fieldguy:

I've tried assigning a coordinate system to the property data beforehand and attaching it, with the same results.  I've tried importing the map from .dgn with no coordinate system and setting it on the import, with the same results.  I've tied several different coordinate systems and datums, with the same or similar results.

I'm confused about what you are doing...

What sort of data do you have?  From your first post, it almost sounds as if you created your Topo using Civil 3D.  If so, C3D objects are incompatible with Map, and cannot be queried.  They have to be exploded into plain linework (or Extract entities from C3D Surfaces) prior to a Map query.

You really lost me when you started talking about DGNs...  What sort of data are you trying to transform?

[Anonymous]

Hi Sinc:

No the topo is simple linework - not created in Civil.  It was originally created in Microstation and converted to Autocad.  The property mapping is also simple linework - originally supplied as .dgn by the province.  We normally convert it to .dwg and only use .dwg for all our work however I did try importing the original .dgn using Map Import to see if it made any difference.

So -  i have 3 files of plain linework - the first topo file topo is in NAD83, 3TM, 111W and the second topo file is in NAD83, 3TM 114W.  These two correlate fine and end up in the right place   The third is property data in NAD83 10TM.  It's the property data that I can't get to match the topo.

[Sinc]

So you're trying to get everything into...  which system?  3TM 114 West?

I presume you already verified the easy things, such making sure you selected the NAD83 one and not the NAD27 one, and you made sure you had the units set to Meters in all drawings?

If you can post the drawings, I'll take a look at them, and see if I can identify anything that might be wrong.  Or send them to me at sinc at quuxsoft dot com.

[Anonymous]

Hi Sinc:  Yep - the units are all meters, the datum is the same for both:  NAD83.  I'm attaching the two files so you can have a look if you want.

[Anonymous]

I should have added this picture too to give you an idea of where the property should be in relation to the topo

[Sinc]

Well, I'm not really sure what's going on.  But I did notice the following:

• Units for "topo site 17.dwg" are set to millimeters, when they should be meters.
• Drawing "Property Project 17.dwg" appears to have been created from an Imperial template, and has a real mish-mash of Imperial and Metric settings.

I don't think either of those is causing your issue, though.

The big thing seems to be that your "Property Project 17.dwg" appears to be in some coordinate system other than 10UTM-155°W.  Or at least, all of the Northings look like they are 5,000,000m off of what they should be.  Similarly, the Eastings aren't matching up between what they should be.  If you look at that main intersection in your image (Hwy 36 and Hwy 14), it's at approx. 111°47'W and 53°06'N.  However, in your parcel drawing, that same intersection is at 108°31'W and 7°58'N.

So it looks like there is some mixup in your drawings.  Most likely, the "Property Project 17.dwg" is not in 10UTM, or is in some modified version thereof, where they "truncated" coordinates, dropping leading digits, or something like that.

[fieldguy]

I opened your property file and the coordinates are out by 5,000,000 in northing and 500,000 in easting.  You won't get a successful transformation if the source and/or destination coordinate values are wrong.

Try this tool: http://altalis.com/resources_atsquery.html

[Anonymous]

Hi, I am having the exact same problem! I am also in Alberta and got shape files (contours, non-3D) in UTM projection from Altalis, and the labels for those coordinates in a .dgn file which is supposedly in 10TM. I am fairly new to Civil 3D (not to Autocad) and can't figure how to tell AutoCAD to bring in the .dgn portion properly. Altalis told me to bring the .dgn in as 10TM but I can't even figure out how to do that. I don't want to change my drawing projection because I have other information in there as well. Did you figure it out??

Thanks!

[Sinc]

Assuming this is a Microstation DGN file, I don't think you can transform the DGN directly.  I think you need to convert it to a DWG first.  Once you have the DGN converted to a DWG, make sure the DWG is set to the appropriate 10TM system.

Then create a new drawing in your UTM system (or use one of your existing drawings), connect to your 10TM drawing, and use a Map Query to pull the 10TM data into your UTM drawing.  The Map Query should transform the data as it is imported.

[Anonymous]

Hi jtgb,

I don't know if you ever resolved this, but there are two 10TM projections sued in Alberta.  One has a false easting, the other does not.  Both are in the coordinate system definitions, so I suggest you try one then the other.

3 years late to the party 😞