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Thread: Re Projection of LAS files

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    Default Re Projection of LAS files

    I have LAS Lidar data in UTM and want to convert to county coordinates. I know I can attach and query a DWG and have it appear to transform on the fly but I see no way to export in the new transformed projection. Any suggestions would be helpful.

    Thanks, Jim

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    Default Re: Re Projection of LAS files

    Export to SDF then bulk copy to another SDF with that coordinate system.
    But if your dwg has a coordinate system assigned to it and you use the point cloud manager to bring in the las it should transform it on the fly. make sure you use the MAP point cloud tools and not the Vanilla AutoCAD Point Cloud tool.
    J. Murphy
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    The former AutoCAD MAP3D Power User

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    Default Re: Re Projection of LAS files

    See if I got this right.
    1. I use the Data Icon in the Task Pane and the Add Point Cloud option. I already created the index so I add to the map and make sure it is assigned the origin projection, UTM in this case. Save the DWG.

    2. Open new DWG and assign to the County Coordinate, attach UTM DWG, and query in point cloud.

    3. From here I cannot see how to export it.
    EDITed. I see I should not do step 1-2, just import into county Coord DWG. and export as SDF.

    4. From here I should be able to open or import SDF into another DWG? If not, it looks like you are telling me to export one more time?
    I will try this.

    5. So when I get this done, I am sure it will work, can I create surfaces and contours from the SDF connection?

    I will try Monday, so thanks Murph

    Jim
    Last edited by jim.dahl; 2011-02-11 at 09:17 PM. Reason: new info

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    Default Re: Re Projection of LAS files

    Jim,
    If your gaol is using the Lidar data to create a surface and contours then this is what I would do. Forget about the export to SDF and all that for now.

    In a new dwg, set the coordinates to the UTM coordinates the LAS is in. Use the "Tool-Based-Ribbon Workspace" It has all the tools there even if you don't like the ribbon.
    On the Create Tab of the ribbon, click on Create Index in the Point Cloud panel. The Point cloud manager should open, select the las file and set the coordinates for it, then create the index. (over write any you may have) After a few minutes of MAP3D sitting there the ADD to MAP button should be ungrayed, meaning the index is created. Click add to the MAP. Zoom to the extents.

    Now depending on how the LAS was created and classified you can style it on the elevations or a few other options for display only. But if all you want is a surface, click on the Create From Point Cloud on the ribbon (3D Surface panel).

    The Surface Manager palette should open, click the add file button and select your .isd file (the index file you created from the LAS file). For the parameter use the default GeoTiff, Filter none for now, Out put to your choosing. Then make sure you highlight the idx file and click create surface.

    What this does is creates a raster surface that you can use with the data connect to style and create SDF contours from the coordinate system you assigned to the dwg at step one (UTM) should be assigned to it. How if you open your base files in your Country coordinates system and that CS is assigned to it when you data connect to the Raster Surface it will transform it to your coordinates. Now you can use the Contour create tools to create SDF contours.

    Now the part about the "Filter" in the Surface Manager, depending on what's in the LAS file to start with you may end up with a surface/contours with everything to include buildings and vegetation. You would need to filter those out before creating the surface.

    Some of this you may know already but for anyone else reading it's there. There was a tutorial on all this on the MAP3D subscription site under the Subscription Extensions for 2010 version. Don't know if it's still there or not but take a look if you can.
    J. Murphy
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    Murph
    The former AutoCAD MAP3D Power User

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    Default Re: Re Projection of LAS files

    Hi Murph,

    I am an Engineer out in Oregon trying to work with LIDAR data and am having some challenges. I have some knowledge gaps which have me at a loss.

    I do not seem to be able to bring LAS data into a AutoCad coordinate system. While I am able to get the information out that I need, it is not an elegant solution and I would like to gain a better understanding.

    Previously I have not had any problems with bringing in LIDAR to a specific coordinate base. But this is the first time I have worked without a GIS professional with ArcGIS to hand me the data is form friendly to AutoCad (C3D). The data was created at a county GIS department.

    The raw LAS data (it is Oregon Lambert) comes into AutoCad with no coordinate system and resists efforts to assign it one on import. There is also a Geodatabase.gdb directory with a variety of files which I am sure has the answer but for which I am uncertain how to proceed. I think it is a matter of selecting the appropriate Data Connection; AcrSDE?, MySQL?, ODBC? etc. All of these require a connection name and then one or two additional inputs such as service name, server name, data source name? ect. Which do not appear to be self evident. I had hoped that poking around with notepad might reveal the appropriate choice but so far it has not.

    Is there any chance you might have a simple solution to this challenge?

    Mike

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    Default Re: Re Projection of LAS files

    Mike,
    On the LAS file you need to be sure your dwg has a coordinate system assigned then in the map Point cloud Manager you should be able to assign the coordinate system to the LAS. The Civil3D point cloud tools are not the same as the one for Map3D and it may be disabled.
    As for the gdb file that is a E$RI database and you need the data connect providers installed for it. With 2011 it's part of the Subscription Advantage Pack, some info here on it. For any other version you need to look on the osgeo.org site and find one to match your version then install and edit the providers.xml. Then you can use the data connect to bring in those features/data.
    J. Murphy
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    Murph
    The former AutoCAD MAP3D Power User

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    Default Re: Re Projection of LAS files

    J murphy, have you tried the FDO connect for ArcGIS? It appears that I just copy a file and folder to the Plugins/DataConnect folder and two files to the FDO/bin folder and edit the provider.xml. I get an error and thought you might give a suggestion of anything I missed.

    thanks!

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    Default Re: Re Projection of LAS files

    Quote Originally Posted by jim.dahl View Post
    J murphy, have you tried the FDO connect for ArcGIS? It appears that I just copy a file and folder to the Plugins/DataConnect folder and two files to the FDO/bin folder and edit the provider.xml. I get an error and thought you might give a suggestion of anything I missed.

    thanks!
    I haven't tried it in the final release version of Map3d 2011, the unemployed do not have access to the SAP. I have used the Open-Source one in 2010 versions for the old personnel geodatabase (mdb format back then)
    J. Murphy
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    Murph
    The former AutoCAD MAP3D Power User

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    Default Re: Re Projection of LAS files

    Murph,

    Excuse me for not replying sooner but thanks for the information, it helped me track down a solution without spinning my wheels in C3D.

    Mike

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