Surface created from DEM file - how to smooth

[Kundertk]

Does anyone have advice on how to best smooth a surface created from a DEM file?  Contours produced from the surface, particularly in the flatter areas seem to be following the triangles, so you can see the rectangular nature of the grid.

I've attached a screenshot with the contours shown.  Up to this point when creating the surface, all I did was add a data clip boundary, then add the DEM file (manually within the surface definition, not using the "create surface from DEM" feature).  I had tried some of the options under surface edits & smoothing, natural neighbor interpolation, but the results were still all wonky.  There must be something I'm forgetting to do, or making an error somewhere along in the process.

[antoniovinci]

Would you please share that Dem with us, sir?

[neilyj666]

what is the grid spacing in the DEM?

[Kundertk]

The file is 4.1MB, so it's not going to let me upload it here. I downloaded it from Geobase.ca. The exact file doesn't seem to matter to me - this is a recurring issue when I try to use these things.

[Kundertk]

Measuring the "triangles", I get 22m (approx.) by 15m

[neilyj666]

I think the upload limit is around 5Mb now.

what is the end use for the DEM file data?

[Kundertk]

Just supplementing data around the outsides of our actual topo survey limits - looking more for trends and drainage directions. I plan on just creating a composite surface (with the DEM, then the topo pasted on top of that), mostly for showing contours on a plan. I'm not planning on running earthworks using this data.

[antoniovinci]

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GrapeSquishy wrote:
The file is 4.1MB, so it's not going to let me upload it here

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You can upload it on a file sharing cloud server, e.g. http://ge.tt/

[rmacan]

I'm experiencing the same issue.  I have surface contours that are displayed on the attached image. 

I found the DEM to create the Surface on the following site:

http://keck.library.unr.edu/Search/DEM/

The one I was using is called Desert Creek Ranch.  I created a surface and displayed the contours at 2' and 10' intervals.  

Is there a way to get them to behave like normal contours (eg, no dead ends, dash marks, connecting loops)?  I tried SmoothSurface but it made it worse, unless I  used it wrong, which is entirely possible.  The Help Menu was not very helpful. 

Is there anything I can do to get them to closely match a 7.5 minute USGS topo Quad?

[Kundertk]

I haven't been able to find a way to smooth it.  In  my case, it's because the data is fairly rough - rounded to the nearest meter.  The program is just connecting the dots and leaving me with rather jagged, abrupt contours that look pretty horrible.

Here's a screenie of the data showing triangles, contours and some surface labels at the vertices:

I'll attach a zipped copy of one of the raw DEM files in case anyone really wants to use the raw data, but I don't suppose much can be done when there are so many consecutive points at the same elevation. The program is probably doing what you'd otherwise WANT it to do. Legalese disclaimer for the licensing of the data obtained from Geobase blah blah blah:

http://data.gc.ca/eng/open-government-licence-canada

[neilyj666]

That's about as good as you could expect with 1m level intervals. At technique I use with DEM/gridded XYZ data is to bring it into MAP and cretae a contour layer, then alter properties to bring into Civil. The main caveat is that it works well in areas with decent relief i.e. river valleys & ridges etc but in flat areas it is very jagged

[antoniovinci]

Well, better later than ever, sir...

After converting your Dem to UTM system, I got those attached 10 mt. contours: check 'em out, thx.

[Kundertk]

Haha, this particular projects sat on the shelf for awhile, waiting for other people to do their thing, chasing after approvals, talk about it, write reports, talk some more, write some more reports, etc. Now it's coming back. We'll probably get a real topo survey of the property done, but the preliminary information is always helpful to send to the surveyors, geotechnical consultants, etc. so that they know what we're after, before they hit the field. Thanks for running those. Looks pretty similar to what I was getting.