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Discussion: OL Laser

in: Orienteering; Gear & Toys

Apr 3, 2023 3:29 AM # 
Hello AP community,
Anybody here ever used the open-source program, OL Laser, for basemap generation using LiDAR? I have a question. Hopefully someone can help me with this one. I have installed OL Laser according to all the appropriate instructions and changed the language to English. However, after I select a LAZ file a window pops up and says "Invalid minior fileversion encountered. Expecting not bigger than 2." Then when I click ok another window pops up that says, "Index was outside the bounds of array." I have tried to load in other LAZ tiles into OL Laser from the same dataset and and only 1 has worked (I managed to get all the outputs I needed: contours, cliffs, relief shading, etc.). So far I have tried many LAZ tiles from the same dataset and other datasets and it looks like 10% of the files work and most of them don't. Possibly there are some problems with the file itself, but I don't think so because I have tried this file with other programs and it has always worked for me with no problems at all.
P.S. Spent the whole day today trying to make it work.

Misha B
Apr 3, 2023 8:39 AM # 
I think latest OL Laser version is from 2019 and latest laz files are too new for the library it uses. You may have to use lastool's las2las to convert your laz files to the "fileversion" of laz OL Laser supports. Option -set_version 1.2 should do the trick.
Apr 3, 2023 10:22 PM # 
Since it’s called las2las do I have to decompress my laz file first?
Apr 4, 2023 4:42 AM # 
No. It’s best to just leave it as a laz. For example:

las2las -i input.laz -o output_12.laz -set_version 1.2

It’s 32-bit, so it will error on bigger laz files. I can’t remember but I normally process as 1km tiles if it’s bigger than 60MB. I join the tiles back together with QGIS raster merge. Ask if you need help.

My OL-Laser is set-up pretty extensively. I process three ways: ground only, “veg” all returns, and an “all last returns” grid. All 1m grid size.
Apr 4, 2023 7:22 AM # 
Terje Mathisen:
I strongly encourage you to use either my own programs (with a significant hurdle to start) or the Map Machine from Finland, Kartapullautin!
Apr 4, 2023 3:42 PM # 
Terje, I'm wanting to explore different lidar processing systems to improve my own process (mostly just using OCAD right) and also to be able to teach others better.

Do you have any instructions on your programs or how could I play around with it?
Apr 4, 2023 3:47 PM # 
I don’t use OL-Laser for contours. I use it for intensity, slope, relief, and object height images. I know there has to be a better way, but I use it mostly because it’s fast. It doesn’t support bounding boxes, so you do get artifacts at the tile boundaries.
Apr 4, 2023 5:06 PM # 
Terje Mathisen:
My documentation is way out of date, almost 10 years ago I wrote

which is still an OK starting point, and the programs have been updated regularly since then.
Apr 6, 2023 12:09 AM # 
Thank you everyone, I have tried tiles from another dataset from 10 years ago and they seem to work in both OL Laser and Kartapullautin. However, when I try to import cliffs (as shapefiles) from Kartapullautin into an OOM map (that was georeferenced already by first loading in an OpenStreetMap file) the cliffs seem to be in a totally different UTM zone specified by the file (UTM zone 31 north). This UTM zone is located in or very near Finland, which I assume is where Kartapullautin was created. Can someone help me solve this problem/change the UTM zone and coordinates so that it becomes properly georeferenced with the map?

This discussion thread is closed.