topic Re: How can I read Blob values from Lidar data? in 3D Questions

How can I read Blob values from Lidar data?

GucluSen — Thu, 19 Dec 2013 14:15:25 GMT

Hi,

I've converted LAS data to the multipoint feature class using toolbox function.
Some fields is Blob values like "INTENSITY, COLORRED, COLORGREEN, COLORBLUE"

I should use these color values and intensity values but I can not read or covert blob values to text, char, etc..

How can I read Blob values from Lidar data?

Thanks.

Re: How can I read Blob values from Lidar data?

JeffreySwain — Fri, 20 Dec 2013 10:26:48 GMT

This blog can help expose the fields with the BLOB characterization within them. I am more familiar with the Intensity field, but I suppose within your data that information can also be exposed. Have you tried looking at the fields in ArcCatalog?

Re: How can I read Blob values from Lidar data?

GucluSen — Fri, 20 Dec 2013 11:42:07 GMT

This blog can help expose the fields with the BLOB characterization within them. I am more familiar with the Intensity field, but I suppose within your data that information can also be exposed. Have you tried looking at the fields in ArcCatalog?

I want to use 3D lidar points and color values of these points as a priority.
I tried to convert using "LAS Dataset to Multipoint" function ; .GDB, .MDB, .shp file but I can not read INTENSITY or COLOR fields, all of them is BLOB.

I tried using Oracle DB and using some codes from internet but I can not read these fields.

As logically, INTENSITY or COLOR fields keep number value between 0-255
Then, what is this BLOB value?

How can I convert these BLOB values simple numbers like this;

For a white lidar point;

l COLORRED l COLORGREEN l COLORBLUE l
255 255 255

I want to use these lidar points with CityEngine but CityEngine can not read Multipoint data GDB or SHP etc

Thanks,

Re: How can I read Blob values from Lidar data?

JeffreySwain — Fri, 03 Jan 2014 10:35:45 GMT

Is the lidar imported into a multipoint feature class? If so then the straight conversion would have to include converting the multipoint features into individual points. Once the individual points are created then perhaps the values could be read like this. I am wondering if you have used the RGB symbology of the LAS files within ArcMap through a LAS Dataset and then try to export that into a raster. You can also export the LAS Dataset with the LAS Dataset to Raster tool and select RGB. This might actually be more time efficient, since depending on the LAS file, you may be creating millions of points from the multipoint feature class. I have never tried this workflow, but perhaps this may get you closer to your desired output.