WMS:Compute Basin Data: Difference between revisions

From XMS Wiki
Jump to navigationJump to search
No edit summary
Line 1: Line 1:
When the drainage coverage feature objects are used to create a hydrologic model the area of the polygons can be determined and used in any of the supported hydrologic models. If the points/vertices used to create the feature arcs also have z values associated with them then WMS will make a rough estimate of the longest flow path and slope along such a path. Finally, if you have derived a watershed from feature objects, but have a background DEM you can compute most of the basin data parameters using the following steps:
When the drainage coverage feature objects are used to create a hydrologic model the area of the polygons can be determined and used in any of the supported hydrologic models. If the points/vertices used to create the feature arcs also have z values associated with them then WMS will make a rough estimate of the longest flow path and slope along such a path. Finally, if the user has derived a watershed from feature objects, and also has a background DEM, the user can compute most of the basin data parameters using the following steps:


:#[[WMS:Importing USGS DEMs|Import/Read the DEM.]]
:#[[WMS:Importing USGS DEMs|Import/Read the DEM.]]
:#[[WMS:Importing Flow Directions and Accumulations|Compute the flow directions]] using TOPAZ.
:#[[WMS:Importing Flow Directions and Accumulations|Compute the flow directions]] using TOPAZ.
:#Use the [[WMS:DEM Basins|Polygon Basin IDs→DEM]] command found in the ''DEM'' menu in the Drainage module to assign DEM cells a basin id from the feature object polygons.
:#Use the [[WMS:DEM Basins|'''Polygon Basin IDs→DEM''']] command found in the ''DEM'' menu in the Drainage module to assign DEM cells a basin id from the feature object polygons.
:#Choose the '''Compute Basin Data''' command from the ''Feature Objects'' menu of the Map module.
:#Choose the '''Compute Basin Data''' command from the ''Feature Objects'' menu of the Map module.


Of course, the results will only be approximate since the actual basin boundaries will not have been derived from the computed flow direction data, but it will provide a reasonable estimate. Ideally you will want to derive the basin boundaries from the DEM and flow direction data and then use the [[WMS:DEM Basins|Compute Basin Data]] command in the ''DEM'' menu of the Drainage module.
Of course, the results will only be approximate since the actual basin boundaries will not have been derived from the computed flow direction data, but it will provide a reasonable estimate. Ideally, most users will want to derive the basin boundaries from the DEM and flow direction data and then use the [[WMS:DEM Basins|Compute Basin Data]] command in the ''DEM'' menu of the Drainage module.





Revision as of 20:26, 21 August 2014

When the drainage coverage feature objects are used to create a hydrologic model the area of the polygons can be determined and used in any of the supported hydrologic models. If the points/vertices used to create the feature arcs also have z values associated with them then WMS will make a rough estimate of the longest flow path and slope along such a path. Finally, if the user has derived a watershed from feature objects, and also has a background DEM, the user can compute most of the basin data parameters using the following steps:

  1. Import/Read the DEM.
  2. Compute the flow directions using TOPAZ.
  3. Use the Polygon Basin IDs→DEM command found in the DEM menu in the Drainage module to assign DEM cells a basin id from the feature object polygons.
  4. Choose the Compute Basin Data command from the Feature Objects menu of the Map module.

Of course, the results will only be approximate since the actual basin boundaries will not have been derived from the computed flow direction data, but it will provide a reasonable estimate. Ideally, most users will want to derive the basin boundaries from the DEM and flow direction data and then use the Compute Basin Data command in the DEM menu of the Drainage module.


Related Topics