topic XYZ points from Raster for Triangulation in Data Management Questions

XYZ points from Raster for Triangulation

RonMan — Mon, 04 Jun 2018 04:51:30 GMT

I would like to ask if this workflow for obtaining xyz points from raster data is acceptable.

1. Obtain SRTM data from USGS (usually 30m res.)

2. Define or Project to proper coordinate reference system and Clip to reduce the data.

3. Use the tool raster to point to create points on each center of pixels. Point features created will inherit the z value of each pixel.

4. Use the tool Export feature attributes to ASCII to export the points in csv format to have the x, y, and z.

I would then use the ASCII file containing x, y and z columns in other software like Bentley InRoads to create the surface and do the triangulation in Bentley InRoads.

Any comments on the workflow will be much appreciated.

Regards,

Ron

Re: XYZ points from Raster for Triangulation

DanPatterson_Retired — Mon, 04 Jun 2018 22:50:51 GMT

Looks alright, but why do want to use Bentley? There are other options including open source types if you don't have 3D analyst

Re: XYZ points from Raster for Triangulation

RonMan — Tue, 05 Jun 2018 01:54:41 GMT

Thanks Dan. It is because that is my main work / software at work for road design. It is just that the surface / profile created by this method is rough terrain. Alot of small undulations compared to lidar data or the one from the EU-DEM. For Hydrology study, this is not good terrain. I think i am missing something.

Regards,

Ron

Re: XYZ points from Raster for Triangulation

DanPatterson_Retired — Tue, 05 Jun 2018 01:57:42 GMT

Ron... SRTM is pretty coarse and probably not suited for the level of detail that you need.

Re: XYZ points from Raster for Triangulation

RonMan — Tue, 05 Jun 2018 05:50:51 GMT

Is there any way i can interpolate to add intermediate points between grid of points? Just to make the ground smoother.

Re: XYZ points from Raster for Triangulation

DanPatterson_Retired — Tue, 05 Jun 2018 08:05:02 GMT

Not really IMHO, spline perhaps http://pro.arcgis.com/en/pro-app/tool-reference/3d-analyst/comparing-interpolation-methods.htm

but you still have the input data causing the issue. Smoothing can be done after the fact using things like focal mean to take the edge of highs and lows.

Some interpolators are better than others for reducing the impact of real or artificial data 'anomolies'. If you are smoothing for aesthetics then that is a separate issue from smoothing for things like analysis for hydrologically 'correct' data

Re: XYZ points from Raster for Triangulation

RonMan — Tue, 05 Jun 2018 11:02:55 GMT

Much appreciated Dan.

Thanks,

Ron