Latest Contributions by TedRakel

‎07-07-2015

In the screenshot below, I need to measure W1 and W2. The polygon is shown in green. There are two point features which lie within the polygon shown in dark green. I would like the distance from the points to the polygon boundary measured in a direction perpendicular to the linear feature shown in dark red. I can construct perpendiculars using the IConstructPoint.ConstructPerpendicular method. Is the easiest way to find W1 and W2 to construct perpendicular lines at the points shown and then clip those lines with the polygon?

‎07-07-2015

Thanks for sharing this information. I had the exact same problem.

‎06-24-2015

Thanks for your help.. My raster image is a TIF and it stores float values, so I couldn't use the Data management tools > Raster > Raster properties > Calculate raster attribute table tool. I was able ot use the approach which Xander gave and it helped me find the places where the canopy height was calculated to be negative.

‎06-24-2015

I have processed some LiDAR data to create a canopy height .TIF image. When I view the canopy height in arc map, in the table of contents, it says that the range of the is from -20 to 61. I'm curious where the data is that's below zero, especially where it's -20. Is there a way to query the image and find places where the pixel value is below zero and then zoom to that location in the map? Thanks

‎06-18-2015

I'm writing a model to find all the .las files in a folder and create a Las Dataset from those .las files. I'm using the IterateFiles iterator and set the extension to "las", the period before the extension is not needed. The problem is that there's already a .lasd file in the folder and the IterateFiles iterator matches this. It matches "lasd" in addition to "las". So I end up trying to create a Las Dataset from some las files and a .lasd file, which fails of course. Is there a way to filter out the .lasd file from the file collection? I tried using wildcards in the IterateFiles, like *.las or *.las$ but that didn't work either. I'm using arc gis 10.2.1. Here's a screen shot of the model.

‎06-17-2015

Now that I have a script to perform this, the problem seems to have gone away. I can't reliably reproduce this. I forgot to mention that I'm on arc gis 10.2.1.

‎06-17-2015

I have a Las Dataset with a surface constraint on it. The surface constraint is present and enabled on the las dataset From this las dataset, I have created a layer which represents only the ground points. I wrote a python script to do this. I used the tool arcpy.management.MakeLasDatasetLayer followed by arcpy.SaveToLayerFile_management. However, I notice in arc map when examing the new layer which represents ground points that the suface constraint is present but not enabled. I have to open the properties of the layer which represents only ground points and enable the surface constraint from within arc map. Is there a way to do this programmatically? I have hundreds of these to do because my client's lidar data is organized into many folder representing many flights over many years.

‎06-16-2015

I find the same thing happening to me in arc gis 10.2.1. Did you ever get any help on this?

‎06-16-2015

Thank you all for your help. I'll be showing the DHM to the client soon and see what they say. Thanks again.

‎06-15-2015

Here's a section of the image which is the DSM minus the DEM. The red area seems to be a tree and I use the interpolate line tool to draw a line through it and get a profile graph shown below This indicatest that the tree is about 25 feet above the ground. Is this the best way to determine canopy height from a DSM minus a DEM? The point profile interactive tool seems like it would work better but it's not enabled. It's available from the 'profile graph' button on the 3d analyst toolbar. The 'point profile' tool is described here: ArcGIS Help 10.1

‎06-15-2015

I have a client who has LiDAR data for high voltage transmission lines. They want to be able to calculate the canopy height in areas near the transmission towers. I followed the link here: ArcGIS Help 10.1 to generate rasters of the DSM and DEM from the LiDAR data. I used the GP minus tool to subtract the DEM raster from the DSM raster. Now I'm wondering how to find the canopy height from this. Should I use the 'Profile Graph' tool on the '3D Analyst' toolbar? It seems that the 'Point profile' tool would work a lot better, but it isn't enabled. Thanks

‎06-12-2015

Looks like this was addressed in the 2014 UC video here: http://video.esri.com/watch/3862/arcgis-3d-analyst-lidar-applications I needed a surface constraint derived using the delineate data area model described in the video. Now my DSM and DEM look much better.

‎06-12-2015

Thanks for you help on this. I've been experimenting with the 'LAS Dataset to Raster' GP tool. There are a lot of options. The LiDAR data that I have is of a flight over a transmission line. So it's long and thin and piecewise linear. Here's a screen shot of the vegetation points in arc map (about 3.5 million points) When creating a raster from this, I selected 'Binning' for the interpolation type. For the void fill method, I've tried 'none', 'simple', 'linear', and 'nearest neighbor'. 'nearest neighbor' ran overnight without finishing so I don't know how well it works, it's just not practical with this data. With 'linear' I get this: With 'simple', I get this I think 'linear' is the best option except it ends up void filling way outside the area of the actual lidar samples. Is there any way to restrict the void filling when using 'linear' to within a polygon or to prevent the void filling from extending so far? For cell size I used 3; the las dataset properties report the point spacing as 2.78.

‎06-10-2015

My client wants to keep lidar data in a las dataset and not use terrain datasets or mosaic datasets. They also do not want to create multipoint features in the geodatabase from the las files. I need to create a DSM and a DEM from the las dataset alone. I have read the excellent esri paper available here : http://www.esri.com/library/whitepapers/pdfs/lidar-analysis-forestry-10.pdf This paper gives great adivce on how to create a DSM and a DEM but it requires creating mulitpoint features in the geodatabase, which my client does not want. Is there a way to create a DSM and DEM from a las dataset directly without creating mulitpoint features or using terrain or mosaic datasets? I'm using arc gis desktop 10.2.1. Thanks

‎06-08-2015

I have a customer who has many existing LAS files and expects to get many more over time. These a LiDAR scans of transmission lines and the vegetation around them. Does anyone have an opinion on the best way to handle scans of the same area over time? Can Mosaic datasets help in this? I've thought about using mutliple LAS datasets with something in the name to indicate the date. Any help is appreciated. Thanks

Online Status	Offline
Date Last Visited	‎11-11-2020 02:23 AM

My Ideas

Latest Contributions by TedRakel

Measure width of a polygon at a point within the polygon

Re: Feature's HasOID is false, values are empty

Re: How to find a cell in a raster with a specific value and zoom to it?

How to find a cell in a raster with a specific value and zoom to it?

ModelBuilder Iterate Files file extension matches too many files

Re: Does MakeLasDatasetLayer inherit an enabled surface constraint from the Las Dataset?

Does MakeLasDatasetLayer inherit an enabled surface constraint from the Las Dataset?

Re: LAS to Raster in model builder error using surface constraints

Re: how to measure canopy height from a DSM raster minus DEM raster?

Re: how to measure canopy height from a DSM raster minus DEM raster?

how to measure canopy height from a DSM raster minus DEM raster?

Re: How to create a DSM and a DEM from las dataset alone?

Re: How to create a DSM and a DEM from las dataset alone?

How to create a DSM and a DEM from las dataset alone?

What's the best way to handle deliveries of LAS files over time?

Re: How to create a DSM and a DEM from las dataset...

Re: console app using GeoProcessor managed assembl...

console app using GeoProcessor managed assembly wo...

Re: How to find a cell in a raster with a specific...