Hengl & Reuter poster at Geomorphometry.org/2011
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This document proposes the creation of an open database of digital elevation model (DEM) derivatives from around the world. The database would provide precision, be multi-scale, have an open structure, and provide web access to DEM data and derived products like slope, aspect, and drainage patterns. It would support geomorphometry research through standardized algorithms and allow testing and comparison of methods. The global collection of DEM data and derivatives could advance knowledge and become a platform for improving data standards over time.
Hengl & Reuter poster at Geomorphometry.org/2011
- 1. An open database of DEM-derivatives of the World T. Hengl & H.I. Reuter Global DEM-derivatives Proposed implementation The idea of a global repository of DEM-derivatives is not new. USGS has The database needs to guarantee the following five criteria (Hengl & Reuter been maintaining the global 1 km HYDRO1k (http://eros.usgs.gov) --- a 2008): repository of DEM derivatives (elevation, WTI, slope, aspect, flow direction, flow accumulation, drainage basins and streams). San Diego Supercomputer Precision --- It needs to provide the best estimates of surface measures and Center hosts a project called "Open Topography" objects, derived from the most accurate and current data and al- (http://opentopography.org/) that aims at serving high resolution (LiDAR) gorithms. data and tools. Esri™ will build and host a collection of multiresolution DEM Multiscale --- Input DEM need to reside within a multi-scale GIS so that it can derivatives, starting with SRTM and analytic services against it, as well as be available at various resolutions. higher resolution DEM derivatives for places where the data is freely available. The data will all be available for free on ArcGIS.com. Open structure --- Users should be able to modify and adjust spatial queries to tailor surface measures and objects to fit specific needs. Web access --- The system should provide a high performance cached map services and interactive analytic functions as web services (e.g. viewshed and watershed delineation). Quality --- the input (DEMs) and algorithms should be continually evaluated and improved and maintained to ensure their fitness for use (minimum artifacts). Spatial query GEOMORPHOMETRIC ATLAS Thematic properties DEM - LSP/LSOs type - algorithms - pre-processing steps Function library Spatial properties - coordinate system - spatial resolution *Activate functions LSPs / matching the best - extent (boundaries) Fig. 1: An example of a complete topographic model of the world at resolution of 1 km. For more info LSOs with users’ request according to the see: http://commons.wikimedia.org/wiki/File:Globedem.png organizer criteria WEB-INTERFACE On the other hand, it is difficult for a single investigator or even one group to undertake complex geomorphometry on a New data Outputs global scale --- instead, cooperative type date initiatives (such as the geomorphometry.org) are needed. Fig. 3: Conceptual design for a geomorphometric atlas: a user defines An open database of DEM- various parameters and then downloads the data. Processing and derivation of surface descriptors is done directly on the server. derivatives LSP/LSO = Land Surface Parameters/Objects. We propose here initiation of open Conclusions database of DEM derivatives (a geo- morphometric atlas) --- an international Demand for DEMs and their derivatives, evident from many different network of mirrored servers that will host disciplines and applications, will prompt ever higher expectations for rigor the largest collection of DEM derived and force the global scientific community to commit to an ongoing review of products including reference methods, data standards. The Global DEM-derivatives initiative is a platform for software tools and standards. meeting these expectations. Fig. 2: The landform classification following Such geo-database would support the Iwahashi and Pike (2007). Relief classes References: which are classified using an unsupervised development of knowledge libraries, as nested-means algorithms. Hengl, T., Reuter, H.I. (eds) 2008. Geomorphometry: Concepts, Software, Applications. Developments in Soil Science, vol. 33, Elsevier, 772 pp. well as continued testing and comparison Kleiner, K., 2011. Data on demand. Nature Climate Change 1, 10–12. of geomorphometric methods by the scientific community (Kleiner, 2011). Iwahashi, J. and R. J. Pike, 2007. "Automated classifications of topography from DEMs by an unsupervised nested- means algorithm and a three-part geometric signature." Geomorphology 86(3-4): 409-440. ISRIC - World Soil Information, Wageningen University PO Box 353, 6700 AJ Wageningen, the Netherlands URL: http://www.isric.org E-mail: {tom.hengl; hannes.reuter}@wur.nl