Unable to select origin surface to create cropped surface

[Anonymous]

Hi,

I am trying to create a cropped surface for a grid surface. I am working with civil cad 3d 2018. The attached screen shot is what a I get when I click the surface and press enter to select it. 

I have attached the file that I am working with. It is a map of Kenya. The surface is approximately 69.25 million point. I am trying to crop out one small area of the surface so I can work with it.  I would appreciate any ideas on this issue on where I can get data to make a terrain model of county machakos, kenya.

[Mike.M.Carlson]

Hello I'm sorry you're going to have trouble using the Surface Crop Command on this type of surface.  You created this from the Create Surface from DEM option or GIS Data?

I would data shortcut this Surface from this file that has the link to the source DEM or GIS data.  Then import that DREF Surface into a fresh Drawing.  Then Promote that surface and try the Create Cropped Surface command.

I hope this helps.

[Anonymous]

I used the create surface from Dem on a .adf file.  I'll your suggestion Monday.

[BushW]

Hello @Anonymous

I was following up and did @Mike.M.Carlson help resolve your issue? If so, please reward the post with an ‘Accepted as Solution’ or Kudos, and please also mark a post or posts as Accepted Solution(s) that resolved the issue or answered your question so, other Community members may benefit and thank you for doing so.

Best Regards,

Wendell

[Anonymous]

I was not able to make this solution to the issue work.  I am currently working on a different route to my end goal.  I do plan on getting back to this issue in due time. 

[Mike.M.Carlson]

Can you post the .GIS DEM data, so I can try my method?  

Thanks!

[BushW]

Hello @Anonymous

Thanks for the reply and please post back when you have the opportunity.

Wendell

[Anonymous]

I attached the grid surface of the test .adf file. You can download it here. I have attached screen shots of the download link and the file name. I was not able to up load the .adf file due to it not being a valid extension for uploading.

When I made the data short cut of the xml file to the that was crated for the surface was only 1kb. When I tried to import, civil cad said that I  had not selected a landxml file.  

[Anonymous]

The adf file is in the attached zip folder.

[Mike.M.Carlson]

Thanks...can you please also upload the .adf file shown below?  Or perhaps a website link to the file, if this interface won't let you attach that kind of file?

Thanks!

[Mike.M.Carlson]

ok got it...thanks.

[Mike.M.Carlson]

Hello-

Please watch this short screencast (click link below).  I found that the .adf file is corrupt in some respects.  It seems to have elevation issues and is causing Civil 3D commands to not function correctly.

https://knowledge.autodesk.com/community/screencast/2ae77dec-e88a-45d9-abac-924efa4efe46

[Anonymous]

Thank you that was very helpful and thank you for being so patient,I have never done this type of work or worked with these file types before. Would it be possible that the xml file labeled meta data would have anything useful to fix the elevation issue?

[Mike.M.Carlson]

No problem.  After reviewing the .xml file meta data, it appears this data is based on Kenya's average rainfall in millimeters...not topographic data.  Please see below:

Therefore when you connect to this data Civil 3D is assuming the rainfall data is the X and Y and Z data it needs to build the surface.  You can see this when hovering over the model and looking at the coordinates at the bottom.  Note how they are very small and the total distance across the model is small as well.

You will have to go back to the GIS source and look for DEM topographic data.  I think this data was supposed to be used as Raster data in a GIS Platform.

I hope this helps.  If it does, please consider clicking "accept as Solution", so others in the Community may benefit from what has been shared in this post.

Thanks!

[Anonymous]

Hi,

I knew the small file was rain fall data. I was hoping that is would be a good file to test solutions on since the map file  is 90mbs and  it takes me 15+ minutes to load it.

I have attached the zip folder but I am not sure if it will upload.

I have attached a screen shot of where to find it in the in zipped folder. 

I have attached a screen shot of the zipped folder for the larger file that is the topographic map of Kenya. The highlighted .adf  file is the one to work with. If you could try your solution on that file it would be great.

 If it does not upload, the page to download it is below. 

https://www.wri.org/resources/data-sets/kenya-gis-data#elevation

I have also attached screen shoots of what zip to download.

[Mike.M.Carlson]

Ok thanks for the clarification.  It looks like this data is SRTM data which is based on Geographic coordinates (WGS-84).  In order to build a surface in Civil 3D we need to "project" this data into a cartesian-based mapping coordinates system.  You need GIS software to perform this kind of conversion first before bringing into Civil 3D to build a surface.  If you build a surface from the current format, it will only ready the lat longs thus making the surface super small again. 

Do you know what coordinates system in Kenya you want to work in?  Also, do you have a Site Boundary that you can provide that shows only the area you're interested in?

I can show you how it is done once I receive this information.

[Anonymous]

That would be great.  I was asked to work in UTM Zone 37S and Vertical Datum: New (1960) Arc.  Would 4 gps coordinates that make up a trapezoid work for the site boundry? 

In decimal degrees

North west corner Lat -1.347 Lon37.27

North east corner Lat -1.347 Long  37.29

South west corner  Lat -1.38 Long 37.27

South east corner lat -1.38 Long 37.3

I have a more exact site boundary in a kmz file, but I can't upload it. 

[Mike.M.Carlson · Accepted solution]

Hello @Anonymous

Thank you for providing the bounding box coordinates.  Since your DEM data file is for all of Kenya, having the bounding box to parse the Raster elevation data was key 🙂  Here are the steps I followed:

1. I created an excel file of the bounding box points and imported into Civil 3D
2. Created polygon connecting points and exported a .shp file for use in ESRI ArcMap 10.5 to clip the Raster data set.
3. I used ESRI Arc Map 10.5 to import the .adf raster file and bounding box .shp. 
4. I then used ArcMap to "Project" the original Raster file (lat-long) to the specified mapping projection coordinate system (Arc (1960) UTM 37S; meters)
5. I then clipped that "Projected" data layer to the bounding box and created a XYZ point file for use in Civil 3D
6. I then created a Surface from that XYZ point file path

I have attached the XYZ point file.  You will have to import as ENZ.csv format to your surface.  You should be able to use "Surface Crop" tool now as well.

I will post the Screencast that shows the entire workflow once it uploads.

I hope this helps.