SVO names for [dataset name]

[dhardestylewis]

Dataset Name: HAND Travis Dataset Source: https://web.corral.tacc.utexas.edu/nfiedata/ Sample File URL: https://portals-api.tacc.utexas.edu/postits/v2/824ed2e2c4dd3c4d3ef167d6f8de74e3

Variables

For variables that need to be linked to SVO, please provide variable's name (as it appears in the data file), its description, and its type (categorical or numerical).

1. Filled or carved elevation:
   • description: Hydrologically correct elevation grid with pits removed either by filling or carving
   • type: numerical
2. D-infinity flow direction:
   • description: D‐infinity flow direction grid
   • type: numerical
3. D8 flow direction:
   • description: D8 flow direction grid
   • type: numerical
4. Flowlines:
   • description: preferential pathways of the flow of streams in a watershed
   • type: numerical
5. Channel heads:
   • description: considering the directionality of flow, the uppermost points at which channels bifurcate
   • type: numerical
6. Weight:
   • description: Weight grid
   • type: numerical
7. Accumulated stream source:
   • description: An accumulated stream source grid derived from a stream source grid and is suitable for drop analysis
   • type: numerical
8. Computed stream source:
   • description: Computed stream raster grid, a grid indicating streams, grid cell value 1 on streams and 0 off streams
   • type: numerical
9. D-infinity distance to stream:
   • description: D‐infinity distance to stream which can be average, minimum or maximum of horizontal, vertical, surface or Pythagoras distances to the stream
   • type: numerical

[mariutzica]

@dhardestylewis I have suggested some new terms below. For a few of the variables I would need additional information, if available, to more accurately identify it. Please take a look below and let me know what you think.

1. Filled or carved elevation:

   • description: Hydrologically correct elevation grid with pits removed either by filling or carving
   • type: numerical
   • label:land_surface__corrected_elevation
   • comment:

2. D-infinity flow direction:

   • description: D‐infinity flow direction grid
   • type: numerical
   • label: grid_cell_water__d-infinity_anti-clockwise-from-east_flow_angle
   • comment: [resolved] Is the flow direction given as an angle? If so, how is that angle defined (e.g. counter-clockwise from horizontal)? Or is it given as a number indicating the adjacent cell.

3. D8 flow direction:

   • description: D8 flow direction grid
   • type: numerical
   • label:grid_cell_water__d8_flow_direction_code
   • comment: [resolved] Same question as previous.

4. Flowlines:

   • description: preferential pathways of the flow of streams in a watershed
   • type: numerical
   • label: grid_cell_channel_water_flow__geographic_location
   • comment: [resolved] Are these given as vectors?

5. Channel heads:

   • description: considering the directionality of flow, the uppermost points at which channels bifurcate
   • type: numerical
   • label: channel__uppermost_bifurcation_position
   • comment:

6. Weight:

   • description: Weight grid
   • type: numerical
   • label: grid_cell_channel_inlet__d8_contributing_weight_factor
   • comment: The description from the linked site is "Weight grid of the rasterized inlet points." What do the weights determine? How much water is flowing in at each inlet point? Or something else?

7. Accumulated stream source:

   • description: An accumulated stream source grid derived from a stream source grid and is suitable for drop analysis
   • type: numerical
   • label: grid_cell_channel~stream_source__accumulated_property_code
   • comment: Is the interpretation correct that this is some kind of codified information? Is 'contributing' a more appropriate term here than accumulated?

8. Computed stream source:

   • description: Computed stream raster grid, a grid indicating streams, grid cell value 1 on streams and 0 off streams
   • type: categorical
   • label: channel~stream_binary-mask__presence
   • comment:

9. D-infinity distance to stream:

   • description: D‐infinity distance to stream which can be average, minimum or maximum of horizontal, vertical, surface or Pythagoras distances to the stream
   • type: numerical
   • label: grid_cell-to-channel~stream__d-infinity_separation_distance
   • comment:

[dhardestylewis]

@mariutzica

First, responses to specific variables' comments:

2. "angle in radians anti‐clockwise from east" [http://hydrology.usu.edu/taudem/taudem5/TauDEM51CommandLineGuide.pdf]

3. "1 - East, 2 - Northeast, 3 - North, 4 - Northwest , 5 - West, 6 - Southwest, 7 - South, 8 - Southeast" [http://hydrology.usu.edu/taudem/taudem5/help/d8flowdirections.html]

4. This is the set of polygons contained in a shapefile, the whole set of which considered as a single variable representing the geographic location of streams. [http://hydrology.usu.edu/taudem/taudem5/TauDEM51CommandLineGuide.pdf]

5. the weight grid modifies commands that would otherwise create a raster mask indicating a catchment area to instead indicate the "accumulation (sum) of the weights from upstream grid cells draining through each grid cell" (with the catchment area implicitly being the non-nodata cells) [http://hydrology.usu.edu/taudem/taudem5/TauDEM51CommandLineGuide.pdf]

6. "accumulated" is the key term here: in the sense of this software, floods are "accumulated streams". I'm not certain that "accumulated property code" [http://hydrology.usu.edu/taudem/taudem5/TauDEM51CommandLineGuide.pdf]

Second, a question of my own:

Computed stream source is basically a mask indicating the presence/non-presence of a stream. Is it thus a categorical variable? (Since this information is given in a raster file, the categories are given as 0s or 1s.)

[mariutzica]

Hi @dhardestylewis, thanks for the responses to my questions. To answer your question, yes, the computed stream source is a categorical variable. I changed its type in the list above to reflect this.

With regards to the responses you provided, I've marked the first three as resolved.

For the weight grid, I am still a bit confused by the description. Is this weights grid essentially used in a similar way as described here: http://hydrology.usu.edu/taudem/taudem3.1/ to calculate the contributing area to a cell (except starting with inlets as opposed to outlets)? If so, then we'll leave the name as is and call this resolved.

For the accumulated stream source, I found this description here https://docs.qgis.org/2.8/en/docs/user_manual/processing_algs/taudem/stream_network_analysis_tools.html: This grid nominally accumulates some characteristic or combination of characteristics of the watershed. The exact characteristic(s) varies depending on the stream network raster algorithm being used. This grid needs to have the property that grid cell values are monotonically increasing downslope along D8 flow directions, so that the resulting stream network is continuous. While this grid is often from an accumulation, other sources such as a maximum upslope function will also produce a suitable grid.

I put 'property' in the name to indicate the "some characteristic" that is being accumulated. It is a generic placeholder. If you can think of what characteristic is being accumulated, we can replace it to make it more specific. Otherwise, we can consider this one resolved.