BRAT

Glossary

Glossary

Because field names in ArcGIS are limited to ten characters, there is a limit to how descriptive those names can be. This page is meant to be a reference for what each field in the stream network produced by BRAT is meant to represent.

Current pyBRAT Values

These are values that are presently generated and used by the latest version of pyBRAT (3.0.18 at the time of writing). They are sorted by what stage they are created in, not alphabetically.

FID - This attribute is automatically assigned to every segment in a stream network. Each segment should have a unique FID value.

  • Field Type: “FID”
  • Generation Method: Automatic

Shape - The type of vector that this element is. This attribute is automatically generated. In a stream network, this value should be Polyline.

  • Field Type: “GEOMETRY”
  • Generation Method: Automatic

ReachID - This attribute is generated based on the FID. By creating our own attribute, we give ourselves more flexibility in how we capture data values. For a technician running BRAT, it is effectively identical to FID.

  • Field Type: “LONG”
  • Generation Method: SegmentNetwork.py script or the BRAT Table tool

ReachLen - The length of the polyline.

  • Field Type: “DOUBLE”
  • Generation Method: SegmentNetwork.py script

StreamName - The name of the stream (for example, “Grouse Creek” or “Snake River”). Some datasets come with this value automatically.

  • Field Type: “STRING”
  • Generation Method: Pre-existing in some datasets

StreamID - Generated based on the StreamName when running SegmentNetwork.py or AddAttributes.py. Every reach with the same StreamName value is given the same StreamID value, counting up from 1. Used primarily in the Drainage Area Check tool.

  • Field Type: “LONG”
  • Generation Method: SegmentNetwork.py script

StreamLen - The length the streams, identified using StreamID.

  • Field Type: “DOUBLE”
  • Generation Method: SegmentNetwork.py script

ReachDist - How far a reach is from the headwaters of the stream. Calculated based off of StreamID.

  • Field Type: “DOUBLE”
  • Generation Method: SegmentNetwork.py script

iGeo_ElMax - The maximum elevation found within a buffer around the reach. Used in calculating slope. Extracted from the DEM given.

  • Field Type: “DOUBLE”
  • Generation Method: BRAT Table Tool

iGeo_ElMin - The minimum elevation found within a buffer around the reach. Used in calculating slope. Extracted from the DEM given.

  • Field Type: “DOUBLE”
  • Generation Method: BRAT Table Tool

iGeo_Len - The length of the reach. Redundant with ReachLen, but removal is currently low priority.

  • Field Type: “DOUBLE”
  • Generation Method: BRAT Table Tool

iGeo_Slope - The average slope of the reach. Calculated using iGeo_ElMax, iGeo_ElMin, and iGeo_Len.

  • Field Type: “DOUBLE”
  • Generation Method: BRAT Table Tool

iGeo_DA - The maximum drainage area value found in a buffer around the stream. Extracted from the drainage area raster given, or from a DA raster derived from the DEM (if no DA raster was given).

  • Field Type: “DOUBLE”
  • Generation Method: BRAT Table Tool

iVeg_100EX - The average VEG_CODE value on the existing vegetation raster within a 100m buffer of the reach.

Depreciated pyBRAT Values

These are values that were once used by pyBRAT, but were discontinued for one reason or another.

SegID - Was renamed to ReachID. Served the same purpose. SegLength - ** Was renamed to ReachLen. Served the same purpose. **IsBraided - Was renamed to “IsMultiThr” for accuracy reasons. Served the same purpose. IsMainstem - Was renamed to “IsMainCh” for clarity reasons. Served the same purpose.