How to process .XYZ format data

[RashidiIsa]

Hi everyone,

I'm an undergraduate student, need help for my final year thesis. I have a LIDAR data which is in .XYZ format. How can I process the data to generate a raster files? I have tried using ASCII 3D to Feature Class tool under 3D Analyst/Conversion toolset in ArcCatalog, however, the .shp files generated is problematic. The points do not have height information, hence, I cannot proceed to generate TIN. I do not understand why the software cannot read the Z information from the .XYZ files. Is there any other way to create raster files from the .XYZ files? Really need help..(Note : I'm using ArcGIS 9.3 and the .XYZ files using TAB separator)

Thank you

[PeterStratton]

Could you attach a sample of your lidar data (for download) that includes the column headers and a few hundred rows?  It would be easier to troubleshoot if we can look at a sample of the xyz data you're trying to work with.

[RashidiIsa]

here is the sample of the file...hopefully u can help...thanks...

[JieChang]

The output of the 'ASCII 3D to Feture' tool (Output Feature Class Type: POINT) is a 3D feature class and contains Z information. Run the Add XY Coordinates tool (Data Management Tools > Features) and the Z values will be added into the attribute table.

[RashidiIsa]

Thanks for the advice! 🙂 I've tried the 'Add XY  Data' using sample data (the one that I've simplified) which contains only 1048576 points instead of using the full data and yes, it works..! I can proceed to generate TIN and also raster files.

However, when I tried using the full data which contain 51424541 points, TIN cannot be generated. Is it because of the file size..?

[PrasantaBhattarai]

I would recommend you to create a terrain instead of TIN as there is a limitation on number of nodes with TINs. Once a terrain is created, you can run Terrain to Raster tool to generate a raster surface.

From the help documentation:
The maximum allowable size of a TIN varies relative to free, contiguous, memory resources. 10 to 15 million nodes represents the largest size achievable under normal operating conditions with Win32. Regardless, it's strongly recommended to cap the size at a few million for the sake of usability and performance. Anything larger than this is best represented using a terrain dataset.

[RashidiIsa]

Thanks vattarai..! 🙂

I think it helps a lot by creating terrain to create raster. I've tried the method, and it works.
However, almost half of the data cannot be generated into terrain. Herewith I attach the image of the terrain that I snapped from ArcGIS.

[RashidiIsa]

Can anyone explain to me why is the terrain generated only half...?

[PrasantaBhattarai]

Did you already try re-creating the terrain?

[RashidiIsa]

vattarai,
Sorry for not updating my progress..yes, I did re-creating the terrain and it works...
terrain was successfully generated..
then, I created a raster files using 'Terrain to Raster' under 3D Analyst Tools in ArcToolbox..
however, the raster created looks so rough..Is it because of the 'Pyramid Level Resolution'..? because I've choose 2 for the Pyramid Level Resolution...what does it mean by 'Pyramid Level Resolution' and how it affect the raster file..?