Latest Contributions by JFPrieur

‎05-19-2018

Hi, yes I should have provided more information for my post to be useful. We do species identification at the individual tree level using ALS. We use raster CHM in our segementation software to delineate individual crowns. In order to minimize edge effects (crowns being chopped in two at the edge and being assigned two different ID's) we use a 20m buffer (this is customizable in our software) on each raster tile. For small areas (like Petawawa Research Forest in Ontario, Canada ((100 sq. km.)) I use unbuffered las tiles (made with Tile LAS tool), create LAS dataset->las dataset to raster (25cm resolution DTM, DSM)->raster calculator for CHM (DTM-DSM), split raster with 20m overlap. This works very well. We have other areas that are several thousand square kilometers in size (LAS dataset has 1800 tiles of 1 sq.km each for example) where ArcGIS Pro has no problem displaying the LAS data but creating a 25cm raster and then tiling it as above with the overlap takes a very long time. Whereas tiling LAS with an overlap and then creating the raster from the tiles is much easier and efficient for us. Hope this is clear. Thank you for your reply.

‎05-18-2018

Hello, Would be great if the Tile LAS tool had an overlap setting like the Split Raster tool has. I am a simple man so this is a simple request!

‎11-21-2016

Hello, I have successfully used Extract LAS to clip a las dataset to my study area using a polygon shapefile, the resulting las files having the _clipped suffix I specified. I have a shapefile with thousands of tree crowns that were extracted using our in lab software. We use FUSION and extract all the points from each tree crown (like a cookie cutter) into their own individual las file eg. each tree from each crown polygon has a las file, with the tree_id from the shapefile as the suffix. Is there a way to do this in ArcGIS Pro using the lidar tools, or use model builder/Python somehow to iterate through the shapefile, extracting each tree crown's las points falling under the crown polygon and naming a suffix with the treeid for the resulting LAS file. Many thanks, trying to reduce the number of tools we use, we could also use lasclip which works well.

‎08-22-2016

Hello, having a few issues with some lidar data we recently acquired, it is in LAS format 1.4 with Point Record Format 6. I have difficulty displaying individual LAS strips in ArcMap. There are approximately 30 las strips in our study region. When I use lastools lasmerge and create one big individual LAS, I can create a LAS dataset (which finds the projection information properly in the LAS header) and display it eg. the points are drawn on the display when I zoom in and I can visualize the data. When I create a LAS dataset from a single strip, the process seems to work (the projection and statistics are found as abobe), a LAS dataset is created and the red bounding box shows up. No points are drawn however when I zoom in, even if the percentage of points displayed value in the Table of Contents is NOT 0 eg. It can say 54,8 percent for example but I see no points drawn on the screen. Any tips? When I use the CheckLAS tool (http://www.arcgis.com/home/item.html?id=e49eaa594fb04f7f8827915345a255aa) the only error I get is ERROR: Point record format 6 of version 1.4 is not supported What I find strange is that everything work fine when I amalgamate the 30 las files into one, perhaps lasmerge is fixing something in the process. Does ArcMap 10.3.1 fully support LAS 1.4 format or am I better off downgrading to 1.2. This would be unfortunate because this is a new sensor that gives us 16 bit intensity values, which I would lose in 1.2.

‎05-12-2016

Thank you for the information, yes this is a very specific use case scenario where I will aggregate 25cm resolution lidar canopy height models to 5 or 10m. But the raster tiles containg the 25cm data do not overlap, so I can not aggregate each tile first and then mosaic, which would be much quicker (even with the apparent .ovr issue in my original post). I usually do not make these huge raster mosaics, I calculate metrics and perform random forest classifications on the point clouds using Python and R and use LAS datasets quite often to make DSM and DTM (tiled). Works very well for our purposes usually. Thanks again for the info and I can provide further info if you need a bug report.

‎05-12-2016

Even when you turn pyramids off in the settings (which I mention doing in my post) it still creates overlays .ovr files. And I am making huge .tif files from lidar data so no, I do not think Mosaic Datasets are helpful in my case.

‎05-12-2016

Thank you for the quick reply, I looked in the document, there is no setting that controls this in there either. But I learnt something new, did not know about this utility! It is annoying when making large mosaics since the temporary files get larger and larger and overlays are generated for both. This is on ArcGIS 10.3.1, did not include that in OP.

‎05-12-2016

How does one turn off overlay generation when using the Mosaic(Data Management) tool?. I can turn off pyramids and statistics in the environments settings but .ovr files keep getting generated (even for the temporary *.tif files created during the process) which really slows things down. Must be obvious, I just can't find it! Thank you in advance.

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Latest Contributions by JFPrieur

Re: ArcGIS Pro: Tile LAS overlap setting

ArcGIS Pro: Tile LAS overlap setting

Extract LAS clip individual shapefile records

Questions about LAS 1.4 support and las data not displaying

Re: Turning off overlay generation for mosaic tool

Re: Turning off overlay generation for mosaic tool

Re: Turning off overlay generation for mosaic tool

Turning off overlay generation for mosaic tool

Re: ArcGIS Pro: Tile LAS overlap setting

ArcGIS Pro: Tile LAS overlap setting