Working with Lidar data in WW

[jimmiller]

This topic is devoted to all things related to Lidar data visualization, analysis, and editing. I have been developing a tool for the past couple of years. It is documented and can be run from: http://people.eecs.ku.edu/~miller/Wo...dar/index.html. In addition to basic visualization, interactive capabilities include rendering based on (nearly) any per-point attribute in the file, filtering based on the same, spatial filtering based on airspaces and/or (some types of) shapes in an ESRI shape file. Subsets of a lidar file can be saved. Various editing capabilities exist including adding imagery to the points (stored as per-point RGB) and adding LAS codes to the points based on image files or shape files. The documentation at the web site listed above describes these and other capabilities.

There are two programs documented on the site that can be run: one is a World Wind application that displays the point cloud georeferenced on the globe; the other is a standalone application that offers many of the same interactive capabilities. This non-world wind application is useful for at least two reasons: (i) much larger lidar files (and/or much larger subsets of given files) can be displayed, and (ii) many lidar files do not contain information describing their coordinate projections and hence cannot be reliably placed on the globe.

I welcome any and all to try out the applications, share your experiences, and generally participate in a discussion of all things lidar!

[Brandt]

Nice Work Jim, I’ll be posting links on the Oregon Elevation Framework Implementation Team (DAS-Geo) site soon.

[nlneilson]

With a quad core and fiber optic 100MB downloaded the default file and took a 15 minute break. Nothing on the first app.

The WW app loaded fast but no lidar data.

[j0landre]

We have seen your work for some time. Congratulations for this great job. It has allowed us to test the Sprinfield data lying on the display that you have made on your site.
Finally, we have developed our own solution to display a point cloud.
For the moment, we are able to color points by intensity, classification and elevation.
In input, we are opening two kind of file :
- A las file associated to a proj4 file (for the projection),
- A txt file which contains xyzRGB points.

You can see what we are displaying in the screenshots below.

We also would like to know the maximum file size you are able to open / display in your WWJ app.

Thank you Mr Miller.

[jimmiller]

With a quad core and fiber optic 100MB downloaded the default file and took a 15 minute break. Nothing on the first app.

The WW app loaded fast but no lidar data.

My computer is older and much slower, and I have only a cable modem connection here. I just now timed it, and it took 1 minute 10 seconds to download. Then about another 10 seconds to display. If you consistently see the sort of response you mentioned, I would be happy to help diagnose the problem.

[jimmiller]

We have seen your work for some time. Congratulations for this great job. It has allowed us to test the Sprinfield data lying on the display that you have made on your site.
Finally, we have developed our own solution to display a point cloud.
For the moment, we are able to color points by intensity, classification and elevation.
In input, we are opening two kind of file :
- A las file associated to a proj4 file (for the projection),
- A txt file which contains xyzRGB points.

You can see what we are displaying in the screenshots below.

We also would like to know the maximum file size you are able to open / display in your WWJ app.

Thank you Mr Miller.

Thanks for your comments. It looks like you have done some nice work here as well. As for the largest file I can display: I haven't really tried to pin that down, in part because it depends on a lot of things (computer, memory, etc.). The largest file I have tried has a bit over 48 million points (1260 MBytes). I of course have to uniformly sample while reading. I have rendered in excess of 15 million points from the file that way, but response on my nearly 5 year old MacBook Pro gets rather sluggish!

[jimmiller]

Nice Work Jim, I’ll be posting links on the Oregon Elevation Framework Implementation Team (DAS-Geo) site soon.

Great. I look forward to their comments. Thanks, Brandt.

[nlneilson]

jimmiller
The example on the left may have required me to select a file as I just clicked the default.

The example on the right loaded OK but did not know what was to be shown.
Is the Lidar data just for a specific area?

[jimmiller]

Neither app (LASVisEdit on the left nor LASVisEditWW on the right) are designed to automatically load a lidar file. Both present the "Lidar Controls" window with its invitation to load one of the standard demo files, but both apps were designed for use by people that have their own files to view, hence automatically pre-loading files is an unwanted initial step for them since they would have to wait for the load, then undo it by deleting the file before they could actually start doing their work.

LASVisEditWW (app on the right) will automatically travel to the correct location on the globe once it reads a file and determines where it is to be placed.

[nlneilson]

Thanks for clarifying what the app/s do.

[softwaremike]

Is this work related to issue WWJ-304 (http://issues.worldwind.arc.nasa.gov...s:all-tabpanel)?

Is the code for the LIDAR import/render available?

Thanks in advance,
Mike Johnson

[jimmiller]

The code is stored in a branch of the WW repository. I don't know the current status of or plans for how this branch is to be made available. But I believe the plan is to make that happen at some point.

[softwaremike]

Any chance that branch can be "opened" to the general public? My team might be willing to do some work on the LIDAR capability to "finish" it (depending on what's left for it to be completed?)

Thanks in advance,
Mike Johnson

[jimmiller]

I will have to check on their schedule. I assume you are able to run the app as posted. What facilities do you need that are not there?

[softwaremike]

We have an app in which WorldWind is embedded. Our users would like to be able to plot LIDAR data. I think, from an end-user LIDAR perspective, your app already provides everything our users would need; however, we'd need it in our app, not as a separate app.

Is the LIDAR branch of code the same as your app?