Hi Fellows...
I'm sure there are many ways of skinning this cat and would love to hear your ideas about importing surface terrain and areial photography into Civil 3D. I understand google earths limitations, and especially the lack of precise data. I also understand that there is better data available out there but requires more work than Civil 3D 2012 Google Earth Import. I'd like to hear your ideas or recommendations for either of these two methods.
Second, I have come across Brian Hailey's blog post HERE and attempted to follow it. From the USGS TNM Viewer, I downloaded the archgrid 1/3" NED Elevation and Geotiff files, unzipped, and found the *.adf file. For the life of me, I could build a surface with it, either by adding DEM file to an existing surface, or building a surface by DEM. Does anyone have a recommenndation for a successfull approach.
Finally, I also used Brian's comments posted HERE which discuss getting a DEM surface from Geo Community. unpacked the *.gz file and converted the DDF files using the the SDTStoDEM from University of Arizon (HERE). This DEM surface imported ok (I think), but I could never verify whether the units I inserted the DEM file in as were feet or meters. Likewise, I used mapinsert in attempt to bring in the geotiff file from USGS TNM Viewer, but could not relate it to the DEM above, either in feet or inches.
So...I need to work in feet and like to find the best data and methods for building surfaces in Civil 3D 2013.
Thanks ahead of time for your help!
mikeshick wrote:
unpacked the *.gz file and converted the DDF files using the the SDTStoDEM from University of Arizon
You definely don't need to do that, sir: it's easier to convert directly a .GZ file to USGS_DEM format, by means of the free 3DEM tool.
If your zone is not covered by the 1/9" dems available in some parts of the USA, I guess you won't find free data better than the 1/3" NED ones...
Please note USGS no longer distributes Historical DEM data... haven't since 2006. NED's have replaced them. Using them is another beast. I'll be following this one 🙂
One of the problems you'll encounter with NED's or DEM's is sometimes the units of the datasets are in meters. Some datasets that claim to be in feet have the horizontal units in feet and the vertical in meters. While C3D can transform the data horizontally to imperial units, it does not perform vertical tranformations. You'll have to look for a workaround for that scenario.
In regards to being unable to build a surface from the .adf file, be aware that there are several .adf files inluded in the dataset. The .adf that has the surface data is the one with the largest file size so make sure to choose that one.
Lastly, to ensure your surface is in the right CS and units, you should look at the metadata for the dataset to determine it's units and CS. Then when creating the surface make sure to apply those settings in the import options so that C3D can transform it to your project CS.
There are several posts about this process in the forum.
A work around I've found for the units issue is to import the DEM file into Autodesk Infrastructure Modeler (if you have it). You can then export to a .imx file and then bring that into C3D. It seems to work a lot better then importing the DEM file into C3D directly because you don't have to worry about units or coordinate systems. Just assign an appropriate coordinate system to your C3D drawing and import the .imx file. Hopefully the next version of C3D will import the DEM file with the correct elevatio units.
thanks, Neil, I appreciate your response. I was using the correct *.adf file, but still unable to build a surface from a file that was 456MB.
Also, regarding horizontal transformation, I should be able to import a geotiff (in meters) and then just scale by the correct factor at basepoint 0,0,0 to bring it into feet, correct?
When adding a DEM file to a surface, the dialog box allows you to choose cs input and cs output. Does this provide the translation needed only for horizontal, not vertical.
I suppose the followup by Brian Hailey to use Infrastructure modeler is easier to use. I'd prefer using fewer pieces of software to accomplish the task, but obtaining more accuracy is a high priority.
Thanks,
Thanks, Brian. I haven't touches modeler yet. Would it also import the geotiff, or should that still be inserted directly into Civil 3d?
The geotiff, is it an image or a DEM (it can be either I believe). If it's an image, use FDO or the MAPIINSERT command (yes, there are two i's in that command). If it's a DEM, use AIM.
Double click on it. If it opens and you see an image, then it's an image. If it doesn't show you an image, it's probably a DEM.
A 456 MB file is going to tax the resources of C3D. You'll need a 64 bit OS and probably at least 8 MB of RAM to process it. Allow maybe 30 minutes to process. Watch your resource monitor to ensure it is processing. If not kill it. I don't have any solutions after that. If you only need a portion of the area covered by the DTM, use a data clip boundary to reduce the area of the dataset to reduce processing.
You are correct about applying the CS parameters. C3D will tranform the data to your project CS if the parameters are applied. However it will not transform the vertical units per my previous comments.
It is my understanding that Geotiff's can be converted to DTM's but as far as I know using an FDO connection cannot produce a surface model directly. It will require additional steps (i.e Geotiff to SDF to contours to DTM) and I don't know if it is any more efficient resource wise. I think you can save those steps if you use the more direct approach.
I haven't tried Brians suggestion of using Infrastructure Modeler. It's a novel approach but it requires learning another product. Personally I'd rather not bring another application into the mix. Users (including myself) have enough on their plate learing C3D, Autocad and Map. My first impression of Infrastructure Modeler leaves me uninspired to invest time to learn it. http://forums.autodesk.com/t5/AutoCAD-Civil-3D/Distributing-Infrastructure-and-Civil-3D-Models-in-3D...
If IM is the only capable solution (aside from purchasing another product) then I guess we are stuck with having to utilize it.
Yes...It does tax resources. I do have 16 GB of memory though...and thought it completed processing in some short order, I still was not able to view or build a surface from that adf file, and I'm not clear why. I tried multiple times, no avail.
What is FDO connection?
Yes...I agree. With my structural engineering and architectural work, I'm not too excited about adding software either, if I don't have to. I've never gotten into Map very much.
FDO=Feature Data Object. It is a Map function for displaying common GIS data formats. Look in the Map help system. I don't think it will help you in this workflow, assuming you are wanting a C3D surface object from the data.
If you have no copyright troubles, feel free to give us the link to that monster 456 MB Dem: we could try to decimate it by means of opensource Gis...
mikeshick wrote:
Click HERE.
"Here" where, sir?
Don't forget to add the clipping range, i.e. the lat/long coordinates of left lowest corner and right highest one.
Sorry for the late, sir, I took a couple of days off.
Your Dem has a 1/3" resolution, so I decimated it three times.
Here's my 1 arc-second release, try it and tell me what about:
http://ge.tt/4dLE0fY/v/0?c
Mike,
What coordinate system are you trying to bring it into?