OpenTopography

"OpenTopography facilitates community access to high-resolution, Earth science-oriented, topography data, and related tools and resources.

Over the past decade, there has been dramatic growth in the acquisition of publicly funded high-resolution topographic and bathymetric data for scientific, environmental, engineering and planning purposes. Because of the richness of these data sets, they are often extremely valuable beyond the application that drove their acquisition and thus are of interest to a large and varied user community. However, because of the large volumes of data produced by high-resolution mapping technologies such as lidar, it is often difficult to distribute these datasets. Furthermore, the data can be technically challenging to work with, requiring software and computing resources not readily available to many users. OpenTopography aims to democratize access to high-resolution topographic data in a manner that serves users with varied expertise, application domains, and computing resources.

 OpenTopography data access levels:

Google Earth:

Google Earth provides an excellent platform to deliver lidar-derived visualizations for research, education, and outreach purposes. These files display full-resolution images derived from lidar in the Google Earth virtual globe. The virtual globe environment provides a freely available and easily navigated viewer and enables quick integration of the lidar visualizations with imagery, geographic layers, and other relevant data available in KML format.

Raster:

Pre-computed raster data include digital elevation model (DEM) layers computed from aerial lidar surveys and raster data from the Satellite Radar Topography Mission (SRTM) global dataset. DEMs from aerial lidar surveys are available as bare earth (ground), highest hit (first or all return), or intensity (strength of laser pulse) tiles. Some datasets also have orthophtotographs available. The DEMs are in common GIS formats (e.g. ESRI Arc Binary) and are compressed (zipped) to reduce their size.

Lidar point cloud data and on-demand processing:

This aspect of OpenTopography allows users to define an area of interest, as well as subset of the data (e.g. “ground returns only"), and then to download the results of this query in ASCII or LAS binary point cloud formats. Also available is the option to generate custom derivative products such as digital elevation models (DEMs) produced with user-defined resolution and algorithm parameters, and downloaded in a number of different file formats. The system will also generate geomorphic metrics such as hillshade and slope maps, and will dynamically generate visualizations of the data products for display in the web browser or Google Earth."

http://www.opentopography.org/

http://acid.sdsc.edu/projects/opentopo