Pennsylvania PASDA DEM files - can't make surface

[daniellarkin]

Anyone have any luck using the DEM (GeoTIFF) files from PASDA in Pennsylvania using the Suface from DEM command? I always get this error:

_AeccCreateSurfaceGridFromDEM Unable to read file

I've tried downloading different areas to check, but no luck.

Any thoughts would be appreciated!

[Murph_Map]

You got a link to D/L one from or one small enough to attach here?

[daniellarkin]

Here's a link.

ftp://pamap.pasda.psu.edu/pamap_lidar/cycle1/DEM/South/2006/30000000/38001320PAS_dem.zip

[Murph_Map · Accepted solution]

The meta data lists it as an ESRI Grid raster, and should be able to read it with the raster providers in data connect, however I'm not having any luck with it in AutoCAD. In E$RI ArcGIS Exploder it does load as a raster but comes in way over in Kansas. The data says it was created from ArcGIS 9.2 version and is from 2006 LiDAR scans. I'm thinking it's the old versions of TIF.  

[daniellarkin]

Ah. Well thank you for checking. Maybe I will contact them to see if they are thinking of non ArcGIS users in their data collecting efforts. Thanks again for your time!

[mike.barkasi]

Murph is correct in that the display is off... I seem to recall the PA MAP program imagery set to NAD 83 feet... yet the tiff tile is set to Meter..

The other issue is the performance of civil3d... I suspect the 9.7 million points is why the tile would not load..

The same tile  LAS Data display incorrectly as well...

below is the full 9.7 million unfiltered points triangulated in bentley civil

Mike Barkasi

Bentley civil

[mike.barkasi]

Actually Im wrong the LAS data projects correctly (well it is appearing in Allegheny County..

Below is the link and a screen shot of the LAS Point cloud...

Perhaps you can pull the cloud in ad create the surface from it (we do it with Bentley Civil)

ftp://pamap.pasda.psu.edu/pamap_lidar/cycle1/LAS/South/2006/30000000/

Mike Barkasi

Bentley Civil

[daniellarkin]

Yes, I was able to import the LAS as a point cloud, but got some pretty undesirable results. I think that they "clean" the LAS to make the DEM and contour data, but I could be wrong.

There is also contour data available for the County I am in so I have been using that using the surface from GIS files tools.

Thanks for your input!

In the future try to avoid showing me other programs that do things that mine won't do!  🙂

[mike.barkasi]

Your correct... the LAS shows buildings etc..... However note the LAS is set to NAD83 SP Sout FEET as I suspected... the DEM is set to meters...my guess is that this has something to do whit the errant shift in the DEM tile... I have downloaded other DEMs from the site that are referenced correctly...

As for the software... it pains me to see people struggle

Mike Barkasi

Bentley Civil

[Murph_Map]

---

@daniellarkin wrote:

Yes, I was able to import the LAS as a point cloud, but got some pretty undesirable results. I think that they "clean" the LAS to make the DEM and contour data, but I could be wrong.

There is also contour data available for the County I am in so I have been using that using the surface from GIS files tools.

Thanks for your input!

In the future try to avoid showing me other programs that do things that mine won't do!  🙂

---

A lot quicker using the LAS in MAP3D and creating the surface and SDF contours. 🙂

[daniellarkin]

Nice! Thanks for the direction. You are crazy helpful Murph.

Would there be any type of procedure for stripping out the building points that stick up so much?

[Murph_Map]

I think they may be trees but with Map3D yes you can filter on the ground classification only then create the surface.

[daniellarkin]

Murph sorry to keep bugging you but I am still having a problem.

This is what I was able to do:

1. Create index file in Point Cloud Manager - I used a filter for ground data only. The first time I filled in the coordinat system to PA83-SF, but this put my points off in lala land, so I changed it to none and this seemed to work.

2. In the Surface Manager I added the .isd file that was created. I tried this two ways - once by browsing to the file and once by right clicking on the point cloud under Display Manager and clicking Create Surface.

3. Once loaded into the surface manager I clicked Create Surface, but an error symbol comes up which indicates "Failed to generate file for unknown reason".

I tried changing the parameters to Feet (they were default on meters), cell size to 5 and search radius to 3 but it still didn't work. I also tried creating the .isd file again without a filter and had the same problem.

Any thoughts?  Thanks again.

[Murph_Map]

When yo bring in the LAS file it needs to have a coordinate system assigned for the surface creation if you are using an prior version (2011) there was a hotfix or SP that might of fixed it. If PA-83-SF is the correct CS make sure the dwg has a CS assigned to it too.

[daniellarkin]

Yes I had them both on PA83-SF. I will check for that hotfix.

Thanks!

[daniellarkin]

Good news is that if I have both the drawing and point cloud set to PA83-SF, then I can generate the surface. Bad news is that it is in the wrong place!

ARG! The image tile comes in at 1,320,000 370,000 , which is reasonable, but the point cloud comes in at roughly 2,772,300 324,000 which is way off. The CS is set to PA83-SF for the drawing and for the LAS import.

When I set the LAS CS to <None> in the point cloud manager then the points come in at the right spot but surface cannot be generated.

?!?

[mike.barkasi]

Power GEOPAK or Power InRoads

Mike Barkasi

Bentley Civil

[daniellarkin]

I did not mean to give that kudos.

[annw2]

Do a search on lidar date.  Yes do the deliberate mispell or look at the reply I just posted.

On the home tab, surface, there is an import surface from GIS that works with lots of error notations, but a suface came in.

At least someone else out there is having problems with the PASDA data.

The MAPIMPORT that was suggested on the other post didn't work at all.

[bob_mcdonald]

Our folks here say 

We do see that error quite often.  It’s not due to size in this case, it’s the format of the DEM.  Ask them to provide the DEM in 32-bit instead of 16 bit.

On a separate note, sometimes the DEMs are way too large to process.  Asking them to convert and clip at the same time is preferred.