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Information and discussion related to high-resolution LiDAR topography for the Earth sciences

Category: Data

2011 NCALM Graduate Student Seed Proposal Call Open

Posted on Tue, September 06, 2011 by Chris Crosby in Data • Education • News

Ramesh Shrestha, Director of the NSF National Center for Airborne Laser Mapping (NCALM) has announced NCALM’s annual call for proposals to their graduate student seed project program.  This program collects LiDAR data for up to ten graduate student PIs who require data for their research. Data collection is typically limited to 40 km2 per project and must be targeted at a basic research question in the geosciences.  The proposal deadline is November 1, 2011.  Email announcement:

The National Center for Airborne Laser mapping (NCALM) invites SEED proposals from Graduate Students PIs who need Airborne Laser Swath mapping (ALSM) data (generally covering no more than 40 square kilometers). Proposals must define a basic research question in the geosciences (broadly defined). No financial support is provided to the student, but it is hoped that the data from projects selected in this program will enable new research opportunities and lead to successful proposals for future research. Detail can be found by clicking the link below.

http://www.ncalm.cive.uh.edu/content/seedproposals.html

Comments on this post: 0

Death Valley - Fish Lake Valley Lidar Update

Posted on Sat, July 23, 2011 by Chris Crosby in Data

There has been some discussion recently regarding the status of the Death Valley-Fish Lake Valley lidar dataset collected on behalf of Principle Investigator Dr. James Dolan (USC) under the National Science Foundation GeoEarthScope project.  These lidar data cover the Death Valley-Fish Lake Valley (DV-FLV) fault system on the California-Nevada border and are the last of the EarthScope funded lidar data to be made available through OpenTopography.  The DV‐FLV lidar data were collected by NCALM under the pre‐community driven GeoEarthScope funding structure (GeoEarthScope Lidar Working Group report [pdf]) and thus fell under the standard two‐year embargo period afforded to NCALM data collected for NSF PIs.

In April, 2010, OpenTopography approached Dr. Dolan to obtain these data for incorporation into the already publicly available EarthScope lidar data catalog hosted by OpenTopography.  Other than the DV‐FLV dataset, all EarthScope funded lidar data have been publicly available in point cloud, DEM, and Google Earth form via OpenTopography since initial delivery by NCALM. Dr. Dolan granted permission for the data to be hosted by OpenTopography and the dataset was sent to OpenTopography in June, 2010 by Dr. Kurt Frankel (Georgia Tech).

However, a detailed inspection of the DV‐FLV dataset by OpenTopography staff revealed several significant issues with the dataset related to the initial dataset collection and partial re‐survey by NCALM. OpenTopography determined that the issues with the dataset were sufficient enough to not meet our standards of community data quality and documentation, and thus the data should not be shared until issues were resolved. In brief, the issues identified included:

  • Initial data collection apparently has significant corduroy and positioning problems. A later, smaller, data collection was performed to fill in with better data. As one would expect, collection areas are not perfectly overlapping.
  • Data schemas and attributes are for the two collections are different. Initial collect was ascii XYZ and delivered as separate files for filtered and unfiltered points. Second collect is TXYZI format and unclassified.
  • There is a large positional difference between the first and second collections, including a possible across survey tilt in the dataset. These issues make it very difficult to merge the two datasets.
  • Incomplete delivery of data for the second survey. Point cloud data products delivered to Dolan by NCALM do not cover the full survey region.  Further, the 2nd delivery is lacking metadata.

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Incomplete data delivery:  yellow tiles represent data delivered vs. magenta outline which is extent of re-survey.  The green outlined hillshade image is the extent of the original survey.

Upon identification of the dataset issues described above, an email was sent to NCALM to request assistance with data re‐processing. NCALM determined that these data did have significant problems and that they should be re‐processed using NCALM’s newest kinematic navigation processing methodology. In November, 2010 when NCALM announced plans to re‐process the dataset, they were unable to provide a timeline on account of other, higher‐priority, data processing tasks.

At this time OpenTopography is still awaiting a reprocessed dataset from NCALM to post.  Both Dr. Dolan and OpenTopography have a complete copy of these data and would be happy to share them with users who are interested in working with these data in their current state.  Please contact Dr. James Dolan or OpenTopography if you have interest in these data.

Comments on this post: 0

New Idaho Lidar Website

Posted on Wed, June 15, 2011 by Chris Crosby in Data • News

Nancy Glenn, director of Idaho State’s Boise Center Aerospace Lab (BCAL) and a member of the OpenTopography Advisory Committee, wrote to let us know about a new Idaho LiDAR Consortium website that her group has just released.  The website provides links to news about ILC activities, research, and software tools - including the BCAL lidar tools for ENVI.  The site provides a nice map interface to view ILC data coverage - including planned data collections - and to download data products such as DEMs for certain datasets.

OpenTopography is working with Nancy to ingest a portion of the ILC point cloud data into OpenTopography - the data are currently in our ingestion queue and we hope to have them online soon.

Screen cap - http://www.idaholidar.org/data:

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Comments on this post: 1

Tahoe Standard DEM Data

Posted on Wed, June 08, 2011 by Chris Crosby in Data • OpenTopography Updates

The final piece of the Lake Tahoe Lidar dataset - standard digital elevation model (DEM) and intensity rasters - are now available for download from the OpenTopography standard DEM page.  These products, produced by Watershed Sciences, the vendor who performed the Tahoe data collection, consist of three separate data layers all at 0.5 meter resolution in the ERDAS Imagine (.IMG) format:

    1. Highest hit DEM
    2. Hydro enforced bare earth DEM
    3. 8-bit intensity raster

We’ve packaged the data based on the USGS quarter quadrangle (3.75 minute) naming conventions used by Watershed Sciences (Tile index file in shapefile format).  Thus, each quarter quad .zip file contains the three grid data products noted above.  For example:

    39120A22.zip corresponds to USGS quarter quad 39120A22 and contains the following three grid products stored in sub-directories:
    - hh_39120A22 (highest hit)
    - he_39120A22 (hydro enforced bare earth)
    - int_39120A22 (intensity grids)

There are 55 quarter quads worth of data in the Lake Tahoe dataset, for a total of ~17 GB of data (zipped).  The OpenTopography standard DEM download interface uses a Java applet to automate the download.  These are large data files so patience and bandwidth are required. 

Examples images derived from the products contained in 39120A22.zip (the quarter quad that corresponds to the Homewood Mountain Ski Area):

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Hillshade of highest hit DEM

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Hillshade of hydro-enforced bare earth DEM

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Intensity raster

Comments on this post: 2

Tahoe Lidar Imagery in Google Earth

Posted on Tue, May 03, 2011 by Chris Crosby in Data • Google Earth • OpenTopography Updates

As we announced last week, lidar data for the whole Lake Tahoe basin are now available via OpenTopography.  Over the past week this dataset has seen a quite a bit of traffic, with over 160 jobs run (10+ billion points processed) by more than 50 unique users.  However, our experience indicates that a large number of people just want to look at these data, and processing point cloud data to DEMs is clearly not the most efficient way to go about this.  So, as I’ve done in the past for many of the larger datasets OpenTopography hosts, I ran the whole Tahoe Basin dataset through a routine to generate lidar derived imagery (hillshades and “slopeshade” images) that can be viewed in Google Earth.  The resulting KMZ file can now be downloaded via our Lidar Derived Imagery in Google Earth page. 

The file provides access to four layers of imagery, all at half meter pixel resolution:  45 and 315 degree sun angle hillshades of the hydro enforced bare earth grid, a slopeshade of the hydro bare earth grid, and a 315 degree sun angle hillshade of the highest hit (vegetation, buildings etc) surface.  See images below for an illustration of the four imagery layers.

Once you download and open the KMZ file in Google Earth, the imagery is streamed from OpenTopography servers at San Diego Supercomputer Center to the Google Earth client for viewing.  This is a large dataset (~14 GB of imagery) so initial display of the imagery can be sluggish, especially if your internet connection is not great.  As you browse the data Google Earth fills its cache, and browsing speeds should pick up.

This set of imagery took somewhere in the neighborhood of 96 hours of time on my workstation to generate.  But it is an excellent method for reducing an otherwise massive dataset down to something that is relatively easy for anyone with a computer, a network connection and Google Earth to access:

  • Original Tahoe lidar point cloud dataset = 325 GB of LAS data (12.4 billion points)
  • Tahoe Basin half meter DEMs generated from point cloud data (bare earth + highest hit) = 64 GB
  • Four layers of imagery (pngs) tiled and pyramided for display in Google Earth = 14 GB

So, through this approach a 325 GB dataset is reduced to something small enough to be delivered dynamically across the network to users with a widely available, free, and familiar and intuitive client.  It is important to note that the Google Earth imagery layers are not meant to be a substitute for going back to the actual elevation data to perform your scientific analysis; but for initial synoptic browsing, site selection, and education and outreach applications it is hard to beat the Google Earth approach.

Check out the images below, download the Tahoe Lidar Imagery KMZ file, and enjoy these amazing data.

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Emerald Bay.  Highest hit image - 315 degree sun angle

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Emerald Bay.  Bare earth image - 315 degree sun angle

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Emerald Bay.  Bare earth image - 45 degree sun angle

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Emerald Bay.  Bare earth image - slopeshade


For fun:
The famous Tahoe Fume Trail, a well known mountain bike ride on the east side of the lake is barely visible in the imagery in Google Earth:

image

But when viewed in the slopeshade lidar imagery, the trail is visible contouring 1600 feet above the lake shoreline clear as day:

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For more information about the Lake Tahoe Basin Lidar Dataset, please see the initial OpenTopography news item HERE

Comments on this post: 2

NOAA-Funded Project Mapping Offshore San Andreas Fault

Posted on Mon, October 04, 2010 by Chris Crosby in Data • News

A NOAA expedition that concluded this past Sunday focused on mapping the offshore extent of the San Andreas fault at high-resolution.  Using sonar mapping and other imaging and geophysical technologies, the NOAA-funded group, led by Chris Goldfinger from Oregon State University, is building a 3D model of the fault that they hope will reveal information about earthquake behavior as well as the role of the fault in undersea life:

While the fault on land is obscured by erosion, vegetation and urbanization in many places, scientists expect the subsea portion of the fault to include deep rifts and high walls, along with areas supporting animal life. The expedition team is using high-resolution sonar mapping, subsurface seismic data and imaging with digital cameras for the first-ever three-dimensional bathymetric-structural map that will model the undersea Northern San Andreas Fault and its structure. Little is known about the offshore fault due to perennial bad weather that has limited scientific investigations.

Combined with the existing high-resolution topography data collected along the San Andreas by the EarthScope project (and an earlier NASA/USGS funded project), there will now be a high-resolution model of fault geomorphology for the full length of the San Andreas, from near the Mexican border in Southern California, to the fault’s northern terminus at the Mendocino Triple Junction offshore Northern California. 

More information: ”NOAA-Sponsored Scientists First to Map Offshore San Andreas Fault and Associated Ecosystems”

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Image via NOAA press release: ”Image courtesy of San Andreas Fault 2010 Expedition, NOAA-OER” Caption: ”This image shows the subsurface San Andreas Fault, approximately eight miles offshore Fort Bragg, Calif. The fault scarp, or step-like feature is 30-50 meters high. The depressions shown next to it, called “sag ponds” on land, result from small changes in the trend of the fault.”

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Call for NCALM Student LiDAR Seed Proposals

Posted on Mon, September 27, 2010 by Chris Crosby in Data • News • Research

The National Center for Airborne Laser Mapping (NCALM) has issued their annual call for proposals to their graduate student seed project program.  This program collects LiDAR data for up to ten graduate student PIs who require data for their research. Data collection is typically limited to 40 km2 per project and must be targeted at a basic research question in the Earth sciences.  Email announcement:

The National Center for Airborne Laser Mapping (NCALM), funded by the National Science Foundation (NSF), invites proposals from graduate students seeking airborne laser swath mapping (ALSM) observations covering limited areas (no more than 40 square kilometers) for use in research to earn an M.S. or Ph.D. degree.  Proposals must be submitted online.  For background information and complete guidelines for submitting a proposal, please see http://www.ncalm.org.  The deadline date for proposal submission is November 1, 2010.  For more information contact NCALM@EGR.UH.EDU or call 832-842-8881

See http://www.ncalm.cive.uh.edu/content/seedproposals.html for more information

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Media coverage of El Mayor-Cucupah earthquake rupture LiDAR dataset

Posted on Thu, September 16, 2010 by Chris Crosby in 2010 Baja EQ • Data • News • Video

Palm Springs CBS TV affiliate KPSP has a nice report and video from the Southern California Earthquake Center (SCEC) annual meeting this past week highlighting the recently collected LiDAR data along the surface rupture of the April 4th, 2010 El Mayor-Cucupah earthquake in northern Baja California.  Results from analysis of preliminary data products were presented at the SCEC meeting.  The video features Mike Oskin of UC Davis, and OpenTopography Co-PI, Ramon Arrowsmith from ASU.  Read the article and view the video here: Scientists: It’s Now Easier to Predict ‘The Big One’

These data were gathered by the National Center for Airborne Laser Mapping with funding from the National Science Foundation and SCEC.  Processing of these data is currently underway, and all data products will ultimately be freely available from OpenTopography.

Scarp from 2010 El Mayor-Cucupah earthquake:

DSC_4675

Via Ramon Arrowsmith

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LiDAR Beginning to Appear in Google Maps Terrain Layer

Posted on Fri, July 30, 2010 by Chris Crosby in Data • Google Earth • Google Maps

One of my favorite features in Google Maps is the terrain layer, which provides a shaded relief (aka hillshade) view of the topography derived from a digital elevation model.  Google has done a nice job generating a visually pleasing terrain layer, and we use it for all of our Google Maps-based interfaces in OpenTopography.  Google appears to use a range of digital elevation model data sources to derive the terrain layer.  Throughout the US, it appears that the terrain layer comes from either 10 or 30 m (1/3 arc-second & 1 arc-second respectively) DEMs from the USGS National Elevation Dataset (NED).  Globally the terrain data appear to be derived from either Shuttle Radar Topography Mission (SRTM) data or something like the NOAA Global Land One-km Base Elevation Project (GLOBE) dataset.  Recently however, I’ve begun to notice higher resolution data in the Google Maps terrain layer.  These higher-resolution data are localized, and are patched into the terrain layer among the standard 10 and 30 m derived images, but they are impressive when you find them.  Based on the location of these patches of high-resolution terrain, and their appearance, it is pretty easy to deduce that Google is now incorporating bare earth LiDAR digital elevation models into the Google Maps terrain layer.

Thus far, I’ve noticed high-resolution data in downtown Portland, OR, the greater Los Angeles area, and Mount Saint Helens in Washington.  There may be other examples of LiDAR-derived terrain in Google Maps since I haven’t searched very hard.  If you are aware of other areas leave a comment.

Below are a few sites in Google Maps where you can clearly see the high-resolution data.

Downtown Portland, OR.  Data are sourced from the Oregon LiDAR Consortium managed by the Oregon Department of Geology and Mineral Industries (DOGAMI).  Note obvious building foundations, hillslope modifications, etc.:


View Larger Map

Edge of LiDAR near Washington Park in Portland - bare earth LiDAR on the east side, 10 m (?) data on the west:


View Larger Map

LiDAR bare earth data near Beverly Hills, CA.  I’m not sure of the origin of these data - does anyone know if the original LiDAR point cloud and DEM data are publicly available?:


View Larger Map

Obvious seam between LiDAR grids and lower resolution terrain data north of Yorba Linda, CA:


View Larger Map

Finally, the very impressive Mount Saint Helens data.  Presumably these are the data collected by NASA in partnership with USGS in 2003-2004 during a period of significant volcanic activity:


View Larger Map

It is really nice to see these high-resolution terrain datasets making it into such a common and easily accessible platform like Google Maps.  OpenTopography provides network-linked KMZ files to deliver LiDAR derived imagery data to Google Earth so that they are available to non-expert users, and direct incorporation of these data into the Google Maps terrain layer takes the accessibility of these data one step further.  As the number of public domain LiDAR data collections increases, I’d expect that we’ll see more examples of LiDAR appearing in maps and online visualizations accessible to the general public. 

An interesting, and logical follow on question to LiDAR in Google Maps, is when will Google will tackle the integration of high-resolution terrain data into the topographic mesh in Google Earth?  For the Earth science community, 1 meter terrain data in Google earth would be revolutionary.

Comments on this post: 7

Recap: Accessing Haiti Earthquake LiDAR Data

Posted on Mon, June 21, 2010 by Chris Crosby in 2010 Haiti EQ • Data

Following the January 12th, 2010 Haiti earthquake I wrote a number of blog posts related to the post-earthquake LiDAR data that were collected by the Center for Imaging Science at Rochester Institute of Technology (RIT), Kucera International, and ImageCat, Inc (with funding from the World Bank), and the National Geospatial Intelligence Agency (NGA).  As a result of these posts OpenTopography gets quite a bit of traffic from people looking for information about these data.  Although discussed in previous posts, we still get emails asking how to access the data.

Given that there appears to be some confusion, here is a quick summary of how to access the publicly available Haiti lidar data products.  If you are aware of other pathways to the data leave a comment and I’ll update the list.

Point cloud data:


UPDATE August 5th, 2010: OpenTopography is now hosting the full World Bank - ImageCat Inc. - RIT Haiti Earthquake LiDAR point cloud dataset.  You can access these data HERE.


Gridded Products (DEMs):

Google Earth Image Overlays:

    Using the gridded World Bank LiDAR data downloaded from the USGS FTP site above, I generated a cache of hillshade imagery and a network linked KML file to access these images in Google Earth.  Download of the KML file and more information can be found in this blog post: Haiti LiDAR imagery in Google Earth

NGA ALIRT LiDAR:


Comments on this post: 0

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