Many standard software packages require the. The aspect data set describes the direction of maximum rate of change in the elevations between each cell and its eight neighbors. These data sets cover many of the common derivative products used in hydrologic analysis. Compound Topographic Index 3. Comparison of the generated streamlines with mapped hydrography allows identification of essentially two types of errors in the DEM: This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.
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USGS EROS Archive – Digital Elevation – HYDRO1K
Identify Natural Sink Features 3. The hydrologically correct DEM and ancillary data layers are useful in studies of earth systems including watershed analysis, landform studies and global change scenarios. This value corresponds directly with the upstream watershed contributing area. Aspects of cells of zero slope flat areas are assigned values of The following keywords are used in the header file: In the case of an error of omission, the newly identified sink feature is “seeded” in the DEM and in the case of inclusion, the “seeded” sink is removed “unseeded”.
File Extension File Type. The drainage basins distributed with the HYDRO1k data set suite are derived using the vector stream networks along with the flow direction data set.
The effort has been led by U. Filling the DEM 3.
Many standard software packages require the. As an example of the naming convention used, the North American data sets that are available are: These data sets cover many of the common derivative products used in hydrologic analysis.
All the data layers are bit data with the exception of the flow accumulation layer, which, due to the range of values needed, is bit. The collection are located under the Digital Elevation category. It is measured in positive integer degrees from 0 tomeasured clockwise from north. If you do not have the gzip and tar utilities, they can be obtained from the following locations: This information is provided with the understanding that it is not guaranteed to be correct or complete and conclusions drawn from such information are the sole responsibility of the user.
The goal of the project is the development of a globally consistent hydrologic derivative data set. Y-location of center of upper-left pixel projected meters. The procedures followed in development of this DEM are iterative. These files, along with the compressed vector export files, must be uncompressed. Always zero Rotation term: In the past, users would obtain the DEM data, process the data, extract the derivative information, use the derived products in their studies and, perhaps, share the derived information with others.
ISLSCP II HYDRO1k Elevation-derived Products
Each raster data layer is provided as four files, with the extension of each file defining the file type. Cells with undefined direction of flow represent sinks and have flow directions that are simple combinations of its neighbors’ flow direction values. Detailed descriptions of the processing steps involved in development of the HYDRO1k data sets can be found in the Readme file.
Please note that some U. To access this account: This was used as a “first-cut” on identification of the natural sink features.
ISLSCP II HYDRO1k Elevation-derived Products,
It is used to detect spammers. Data Processing Procedures 3. X-location of center hysro1k upper-left pixel projected meters. Some of the techniques used in the DEM development are documented in Danielson