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Microstation / DGN to ArcGIS - Projection help needed

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#1
David T

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I have a set of Microstation files (DGN's) that I need to get into ArcGIS. That isn't the problem I'm having. We are able to get the files into ArcGIS without a problem.

The problem is the projection. We thought we knew what the projection was. But, the data is not projecting correctly. We do not have Microstation. If we had Microstation, would we be able to view the projection information?

Does anyone have Microstation, and are you willing to take a look at one of my files, to determine the projection information (if that is possible)?

Thanks in advance.
David Toney, GISP
GIS Manager
United States Marine Corps
West Coast Installations

#2
Hans van der Maarel

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The problem is the projection. We thought we knew what the projection was. But, the data is not projecting correctly. We do not have Microstation. If we had Microstation, would we be able to view the projection information?


No, Microstation only saves coordinates, no projection information whatsoever. In fact, "coordinates" is an exaggeration, it saves integer numbers without telling you what the units are, so there's a potential error there as well.

How many likely suspects are there for projection? If it's only a few, you could try them one by one until you find the right one, then apply that to all files.
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#3
DaveB

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Here is some info from one of my colleagues (Melita Kennedy, our resident coordinate system product engineer/guru):
"If you have some possibilities, here is what you can do.

Add some known data to ArcMap that's in the same area. Now
add the unknown data. Because it has an unknown coordinate
system, ArcMap can't project it on-the-fly. The unknown data
will remain where it is in the data frame.

Now open data frame properties and switch to the coordinate
system tab. Set the coordinate system of the data frame to
what you think the unknown coordinate system might be. If
you can get the known data to line up with the unknown data,
you've found the coordinate system of the unknown dataset. "

If you defined a coordinate system using ArcCatalog make sure you undefine it back to unknown before trying the above.
Once you get it to line up with known data then you can define the coordinate system in ArcCatalog (or right-click on the layer in the TOC, xport the data to a new dataset using the data frame's coordinate system).
Dave Barnes
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Map Geek

#4
David T

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The problem is the projection. We thought we knew what the projection was. But, the data is not projecting correctly. We do not have Microstation. If we had Microstation, would we be able to view the projection information?


No, Microstation only saves coordinates, no projection information whatsoever. In fact, "coordinates" is an exaggeration, it saves integer numbers without telling you what the units are, so there's a potential error there as well.

How many likely suspects are there for projection? If it's only a few, you could try them one by one until you find the right one, then apply that to all files.


I was told the data was California State Plane, NAD27. We've tried both NAD27 and NAD83, but haven't had luck. We're going to try UTM Zone 11 (our local zone) in both NAD27 and NAD83, to see if that might do the trick. There should only be a couple of possibilities. But, if someone went out on a limb and did something weird...

But, we're going to give those a try, first.

Here is some info from one of my colleagues (Melita Kennedy, our resident coordinate system product engineer/guru)


Thanks for the suggestion Dave. I am passing along those steps.
David Toney, GISP
GIS Manager
United States Marine Corps
West Coast Installations

#5
rmcculley

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I often get microstation files, and I know the proper projection, and they still don't line up properly. One of our engineers has a series of about 100 microstation files, all in the same projection, and probably about a quarter of them don't reproject propery for me. I've never figured out why.

I usually end up using the Spatial Adjustment tools in ArcGIS to fix the problem. It doesn't always work out perfectly, but depending on the data, I can get very good results using Spatial Adjustment.

If you've got many files to do, and you can identify the coordinates of common points, there is a method of scripting the spatial adjustment in GRASS.

#6
ProMapper

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Hello

Though the lead is a little old but I have worked on Microstation J but not V8. The dgn files have type 66 elements and that contain the projection information. If you want to view the projection information then you need Intergraph software called MGE Co-ordinate system Operations which comes bundled with IRASC, IRASB, IGEOVEC and other Intergraph software. Here you can easily find out the Projection information.

And if you have the MGE Projection Manager (another Intergraph Software) then you can change the projection to any projection including custom projections. The Projection Manager can do datum transformation too, if you have the parameters for that. I had used Molodensky and Bursa Wolfe with excellent results for conversion from WGS84 to Everest datum.

The whole mapping environment with Microstation is a little complex but gives excellent accuracy.

Promapper
http://www.mapsandlocations.com

#7
eli

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hey dave,
thanks for this. i found it very useful. a couple things i did a bit differently though... i converted the dgn to a shp first, and then i changed the coordinate system of the shp in arccatalog instead of arcmap. i was super lucky, as it lined up on the second try!

#8
Tonny

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If you want to know all usefull informations about your dataset, check, assign or reproject the coordinate system to it, or convert CAD/GIS data do other formats, you can use on-line GIS data converter at http://converter.mygeodata.eu - it helped me quite much...




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