topic Re: Creating DEMs from LIDAR multipoints in Data Management Questions

Creating DEMs from LIDAR multipoints

ScottLouque — Tue, 01 Jul 2014 16:07:02 GMT

I have LIDAR multipoints and would like to group them into tiles and then make DEMs out of the tiles. All my multipoints are stored in a GDB format. Can anybody put me on the right path on how to accomplish this? This is my first time fooling with LIDAR data and I want to learn about elevation data.

Thanks,

Re: Creating DEMs from LIDAR multipoints

IanMurray — Tue, 01 Jul 2014 16:29:24 GMT

Hi Scott,

If you have multipoint files, the best way I know to make a raster is to use multipoint to terrain tool, then terrain to raster. If you need to have them tiled together, I would create a mosaic dataset, then you can add each of your raster DEMs to the mosaic dataset. If you have actual .las files, you can add those directly to a mosaic dataset, or add them to a las dataset (.lasd) and use that to generate your dem.

I'm not overly familiar with the multipoint route, I prefer .lasd usually, since it makes it easier to handle the points and returns, and I'm not sure of a way to convert back from multipoint to a las file.

If anyone else has some good input, I'd love to here it.

http://resources.arcgis.com/en/help/main/10.1/index.html#/A_quick_tour_of_lidar_in_ArcGIS/015w00000066000000/

http://resources.arcgis.com/en/help/main/10.1/index.html#//009t0000003p000000

Re: Creating DEMs from LIDAR multipoints

ScottLouque — Tue, 01 Jul 2014 16:34:48 GMT

Thanks for the reply IamMurray! What I was going to try and do is just use the Select By Location tool in ArcMap and select all the points that fell in the tile and just create my tiles that way and then just create the DEM files from that but I've never done this before so thanks for the help

Re: Creating DEMs from LIDAR multipoints

ScottLouque — Tue, 01 Jul 2014 16:59:37 GMT

I'm not seeing a multipoint to terrain tool. Is there anything I need to enable to get access to it? Or what toolbox is it in?

Re: Creating DEMs from LIDAR multipoints

IanMurray — Tue, 01 Jul 2014 17:09:43 GMT

Sorry I stole that multipoint solution from another thread, and didn't check for the actual tool

That thread can be found here.

http://gis.stackexchange.com/questions/78961/proper-workflow-for-las-to-dem-conversion

Apparently it takes a few tools to build a terrain, see this link.

http://resources.arcgis.com/en/help/main/10.2/index.html#//005v0000001p000000

Do you only have multipoint files, or could you obtain the .las files?

Re: Creating DEMs from LIDAR multipoints

ScottLouque — Tue, 01 Jul 2014 17:53:38 GMT

I used the Point to Raster tool and it created me an .adf file which I'm reading is a raster grid file. Is there anyway to create a .dem file from this?

Re: Creating DEMs from LIDAR multipoints

IanMurray — Tue, 01 Jul 2014 18:28:04 GMT

A DEM is a raster, just the raster values are the elevation data. So you should more or less have what you need(though you may want to rerun it so your raster has a different file type such as a .tiff, if you are saving it not in a gdb that is). You shouldn't need it to have a .dem extension.

Re: Creating DEMs from LIDAR multipoints

ScottLouque — Tue, 01 Jul 2014 21:06:27 GMT

Is there anyway I can export it out to a .dem file?

Re: Creating DEMs from LIDAR multipoints

IanMurray — Tue, 01 Jul 2014 21:34:29 GMT

Here is a REALLY old thread I found, the only one I could find discussing converting to .dem(apparently the USGS specific DEM format).

Hopefully that can help you out. Guess I'm too new to GIS to know about .dem

Re: Creating DEMs from LIDAR multipoints

ArthurCrawford — Thu, 03 Jul 2014 15:52:00 GMT

Hi Scott,

I would suggest using the Topo To Raster tool instead.   The interpolation procedure has been designed to take advantage of the types of input data commonly available and the known characteristics of elevation surfaces. This method uses an iterative finite difference interpolation technique.

Topo To Raster Tool Help:
http://resources.arcgis.com/en/help/main/10.2/index.html#/Topo_to_Raster/009z0000006s000000/

Description of Topo To Raster:
http://resources.arcgis.com/en/help/main/10.2/index.html#/How_Topo_to_Raster_works/009z0000007m000000/

When I do this operation, I like to set it up in model builder with the polygon tiles going through an iterator feature selection.    It selects the points based of a buffer of the tile to get points outside your tile (say 100m) and then inputs them to the Topo To Raster Tool and use a Clip Raster with the polygon tile on the output to get it back to the original tile size.    This step is important as your DEM tiles will not match each otherwise.

On converting to USGS DEM format, it's does not look like we support that.

http://resources.arcgis.com/en/help/main/10.2/index.html#//009t0000000q000000

Thanks,

Arthur Crawford

Re: Creating DEMs from LIDAR multipoints

ScottLouque — Thu, 03 Jul 2014 15:55:55 GMT

Will give it a try! Thanks Author

Re: Creating DEMs from LIDAR multipoints

IanMurray — Tue, 08 Jul 2014 14:54:36 GMT

I'm terribly sorry, I didn't realize my hyperlink didn't post last time.

Raster to DEM‌

USGSDEM -- USGS ASCII DEM (and CDED)‌

Re: Creating DEMs from LIDAR multipoints

GordonSumerling — Tue, 22 Jul 2014 22:34:58 GMT

Scott,

take a look at the lidar white paper from Esri. It predates the las data set but covers your questions about multipoints to terrain.

http://www.esri.com/library/whitepapers/pdfs/lidar-analysis-forestry-10.pdf‌

hope this helps

Gordon

Re: Creating DEMs from LIDAR multipoints

IanMurray — Tue, 22 Jul 2014 22:51:20 GMT

Gordon, this topic got remade after the transfer to GeoNET, and was answered on this thread

Would like to get rasters into a USGS .dem file.‌

Thanks for the extra info though!

Re: Creating DEMs from LIDAR multipoints

SteveSnow — Wed, 23 Jul 2014 00:03:04 GMT

Hi Scott,

I hope this helps.

try page 13 below multipoint to terrain

check out this lab our team made to address multipoint in 10.2

A quick how to we made on working with Lidar in ArcGIS

http://www.esri.com/~/media/files/pdfs/library/workshops/arcgis102-lidar-workshop.pdf

Good luck,

Steve

Re: Creating DEMs from LIDAR multipoints

ScottLouque — Wed, 23 Jul 2014 12:40:00 GMT

Thanks so much for the info guys! Since I've started working with the multipoints which we accquired from a vendor, I've figured out how to bring them into a feature class and convert them to a raster dataset, then bring the raster images into global mapper and export them out to a DEM file. Which is what I was trying to figure out when I started this thread. But I've also learned how to create las files in Global Mapper and create a terrain dataset from the multipoints.

Thanks for all the help!

Re: Creating DEMs from LIDAR multipoints

SteveSnow — Wed, 23 Jul 2014 16:37:38 GMT

Good luck scott, sounds like a lot of work.

Re: Creating DEMs from LIDAR multipoints

JohannesBierer — Wed, 23 Jul 2014 16:43:58 GMT

Has someone tested this tool?

LASzip | rapidlasso GmbH‌

Should be quite fast?

Re: Creating DEMs from LIDAR multipoints

IanMurray — Wed, 23 Jul 2014 16:50:19 GMT

I've used LASTOOLs quite a bit and they can be very useful.

Re: Creating DEMs from LIDAR multipoints

JamesWeakland — Wed, 23 Jul 2014 17:27:06 GMT

The Alaska Division of Geological & Geophysical Surveys used LASzip successfully in an interactive map called LiDAR Datasets of Alaska.