topic Re: Importing Ascii (.asc) lidar data to create 3d terrain? in ArcGIS Server with JavaScript API Questions

Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Sun, 24 Jan 2016 22:28:27 GMT

First of all, I should mention that I have no experience with height or point data at all. I have an Ascii file of lidar data that I want to create 3d terrain from. I tried to import the file into meshlab and also into a CAD program, but the results differed and were not what I expected at all. So I thought I would try ArcGis Pro. I have not been able to work out how to do it. Any advice would be greatly appreciated. The .asc file is here if you'd like to take a look: ShareFile

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Tue, 26 Jan 2016 00:58:34 GMT

Hi Dan Patterson, thanks for the reply. The results from the mesh are a long flat plane, which isn't as expected. As mentioned I have no previous experience with this, so I'm not sure where the problem is. I hope you don't mind helping here.

I offered to create a DEM for a relative, to help them visualise a plot of land for planning purposes. I have a good amount of 3d visualisation experience, so I thought I'd find this relatively straight forward. The plot itself is very steep, and the surrounding area varies quite a lot, which is why I don't understand why I've managed to get a flat plane for my resulting mesh.

The OS map reference for the plot is SX2553NE, so I downloaded SX25 open lidar data from the governments website: Survey Open Data , and used the SX2553_DTM_50cm.asc file. If it wasn't for my complete lack of experience I'd assume that the height data was just plain wrong.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DarrenWiens2 — Tue, 26 Jan 2016 01:19:58 GMT

I think MeshLab is more for raw pointcloud data, but I could be wrong.

Dan's link to ASCII To Raster works for me:

Hillshade:

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

XanderBakker — Tue, 26 Jan 2016 11:49:44 GMT

To confirm the question, the images Darren posted are based on your file. You can also simply drag the file from the catalog window to the dataframe to display it without conversion:

You will probably have to do some post processing since there are some parts that are likely covered with high vegetation and lack detail:

Other parts appear to have more detail (probably higher point density representing bare earth due to lack of vegetation):

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DarrenWiens2 — Wed, 27 Jan 2016 01:13:18 GMT

Explore 3D data | Learn ArcGIS

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Wed, 27 Jan 2016 01:29:22 GMT

I'll try that out Darren.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DanPatterson_Retired — Wed, 27 Jan 2016 02:34:39 GMT

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Wed, 27 Jan 2016 02:45:36 GMT

I don't know why you deleted all of your posts and are now adding in pictures. If you're not going to help then stay out of the thread Dan.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DanPatterson_Retired — Wed, 27 Jan 2016 02:57:13 GMT

My links had all the information...you just were looking for a detailed step-by-step so there is no point in keeping them. thread can be easily locked if you prefer...just let me know... just showing it can be done with a few paragraphs of reading.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Wed, 27 Jan 2016 03:20:54 GMT

Your initial link makes no sense to someone with no experience, and your second link was irrelevant. You've clearly shown that you're capable of doing it quickly, and with your experience you could have easily broken it down and helped me to understand where I'm going wrong. Instead I've wasted a load of time.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DanPatterson_Retired — Wed, 27 Jan 2016 03:43:20 GMT

your data was proven to work and the tools to create the images were given. That was the ascii to raster tool which both darren and xander used to produce their images as did i.

Did you try the ascii to raster tool? there was no indication that you even tried it. Continuing on to the 3d display you may as well continue with darren's link. My link was perhaps less direct but it contained other pertinent information which might have been useful for the novice.

Once I had your data converted from ascii to raster, the process can be followed. Perhaps Darren or someone else will continue.

Alternately, you might want to Geographic Information Systems Stack Exchange they are somewhat less busy over there. Good luck.

Xander Bakker, Robert Scheitlin, GISP or a mod with privileges to this place, could you move the thread to

Spatial Analyst or New to GIS don't think there is enough traffic on ArcGIS Pro to be of much use. It certainly isn't a server question.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Wed, 27 Jan 2016 04:01:44 GMT

Do you work for Esri?

This is as far as I got to:

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DanPatterson_Retired — Wed, 27 Jan 2016 04:19:19 GMT

no i don't

If you have no experience with gis, why are you using Pro instead of ArMap

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

MrMurren — Wed, 27 Jan 2016 04:23:05 GMT

Because I have no experience with gis.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DanPatterson_Retired — Wed, 27 Jan 2016 04:32:12 GMT

then you are going to have to read ... at least this... Maps and layers—ArcGIS Pro | ArcGIS for Desktop ... and probably more on offshoots like in the one I sent you...but a step down Symbolize your data—ArcGIS Pro | ArcGIS for Desktop that will give you the colours, then you just need to use your raster as your heights and use a 2x vertical (aka Z) exaggeration to stretch the elevations relative to the x,y coordinates.

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

XanderBakker — Wed, 27 Jan 2016 11:10:00 GMT

To add to the explanation by Dan, you will have to use a custom elevation surface: see Elevation surfaces—Properties of maps | ArcGIS for Desktop and set the elevation type to the custom surface: see Define height characteristics for layers—ArcGIS Pro | ArcGIS for Desktop . This can be done in the by setting the elevation properties of the layer: see Set layer properties—ArcGIS Pro | ArcGIS for Desktop

Don't forget to define the projection for the DEM (the raster): see Define Projection—Data Management toolbox | ArcGIS for Desktop

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

Anonymous User — Sun, 31 Jan 2016 03:47:28 GMT

Mr Murren, what is the projection of this data?

Re: Importing Ascii (.asc) lidar data to create 3d terrain?

DanPatterson_Retired — Sun, 31 Jan 2016 03:58:41 GMT

the units are planar, not geographic. the units in the data frame just haven't been set properly to reflect this