Hi Chad
Newbie with TGC and TGC designer tools and old golfer. I came across these two programs the other day in relation to my day job as a civil engineer and was playing around with them over the weekend. Basically I was wanting to find a program to render up quickly a small golf project I am working on here in Queenstown, New Zealand pro bono. We are soon going to lose our community driving range and small 9 hole feeder course due to the expansion of the airport and events centre and I am wanting to demonstrate how an underutilized piece of land in a nearby river delta could be transformed into a great new facility for the community.
I ran into a couple of problems one how could I create a .las file from the design ground surface I had developed partly already in the cad program I use on a daily basis called Civil3d by Autodesk and two how to then classify the point cloud surface data to get your program to except the .las file without bring up an error.
I have been able to develop a workflow that pretty much achieves this using the open source product "SAGA GIS". The program will allow you to classify points manually which was ok in my case as I was only interested in the ground surface as that is all the .las file I was creating was going to contain. To automatically classify a raw lidar file you have to pay for this functionality as an add on. But looking at the internet before I found SAGA GIS i found a number of open source projects cloud compare being one of them that seem to be able to classify raw lidar .las files using various algorithms.
SAGA GIS will also split point clouds by class and take surface data as various file formats SHP, DEM, TIN, RASTER and then convert it into a point clouds and then export as a .las file. This means users of TGC designer are potentially not limited to just finding their golf course surface data as a lidar .las file.
My workflow to date is as follows:-
1. Download and install
SAGA GIS2. From Civil3d I exported a DEM file of the design ground surface I was wanting make into a .las file
3. I dragged the DEM file into SAGA GIS.
4. Using the PointCloud from Grid created a point cloud. (there is a rounding error in the elevation here that I found the anwser for
here)
5. Viewed the point cloud data and added a field for the classification and added 2 for "Ground".
6. Used the Export .las file to export out the .las file.
7. Imported the the .las into TGC designer tools
I have put more detailed instructions with pictures on my blog page
here as could not figure out how to post images easily here. Hope this helps.
I also had a couple of questions for you.
1. With the TGC API is it possible to export back out the amended surface as some sort of file point cloud.
2. When I import the OSM data it does not marry up with my .las data I think this is because I have the .las in the wrong co-ordinate system are you taking the red box in WGS84 co-ordinates and using that to query the data from OSM.
Regards
Justin Ralston
Hi Justin,
I just came across your post and tutorial for using Saga GIS to create a LAS file to use with Chad's tool and I think it is may be exactly what I am looking for, however, I am getting stuck a bit. As I am trying to work on some courses for which I don't have any data, LAS, DEM or otherwise, I am trying to create a DEM from Google Earth by plotting out lots of points, extracting Long, Lat and Alt values and saving as a shape file.
From there, I just need to classify the data and then export to LAS. I had gotten advice from a few people to use this or that (e.g., QGIS, LASTools, CloudCompare, etc.) as well as the more expensive packages such as GlobalMapper or ArcGIS, but nothing really seemed that easy to navigate or to do exactly what I want it to do.
When I came across this post, I thought it could be the answer. I tried to follow the tutorial but the pictures were a little hard to make out and this is what I have done:
1) drag the shp file into Saga GIS
2) Created a point cloud from shape (you had demonstrated with points but I think I can do it from shape. Here I select the file for shape.
3) Showed attributes of the point cloud and added a new field for "class"
4) Next, I go to Point Cloud Reclassifier, choose the Point cloud, select "class" as the attribute, and then change "new value" to 2. I left everything else the same. From here, I select "execute" and then when I check again, it shows the classification alright.
5) I then export the LAS file
Unfortunately, when I run the TGC Golf tool, I get to the point where I select the area, but then I get the error message that the LAS is not classified. When I open Saga GIS again and then ope the LAS file that I exported and view properties, it doesn't show Class as a field. Have I done something wrong with the classification step? I tried opening another LAS file that i know is classified in Saga GIS and when I look at the attributes for that, it also only shows X, Y, Z fields and not Class.
Any ideas on what I may be doing wrong here?
Cheers,
Stephen
