Pixel
The smallest unit of analysis is the pixel. At the landscape level, pixel size is often set to 30 x 30 m, or 0.09 HA. However, pixels can easily be re-sized for any purpose. Each pixel will contain a number of attributes (below). These attributes are stored as GIS rasters.
Pixel properties (i.e. raster data sets):
- Habitat
- Habitat: habitat = 1, non-habitat = NoData
- Binary Habitat: habitat = 1, non-habitat = 0
- Future Habitat: habitat in year [X] =1, non-habitat = NoData
- Distance to habitat edge
- Core habitat: Habitat beyond [X] m from edge = 1, all other areas = NoData
- Habitat patches: Patch ID*
- Patch sub-network: Sub-network ID*
- Distance to habitat: Euclidean or cost-weighted distance
- Distance to protected area: Euclidean or cost-weighted distance
- Threat level
- NHD+ catchment COMID
- Upstream characteristics (% forested, %impervious, etc.)
- Downstream characteristics (e.g., distance to stream)
Patch
A patch is set of contiguous habitat cells. Each patch is assigned a unique ID and several attributes which can be used to assess its overall value in protecting the species in question. These attributes are listed below:
- Size/geometry
- Minimum distance to neighboring patches (Euclidean or cost weighted)
- Minimum distance to nearest protected area (Euclidean or cost weighted)
- Shortest path betweenness (contribution to keeping the sub-network intact)
- Overall threat level
Sub-patch
In cases where habitat patches are larger than the typical area that can be conserved at one time, the patches are divided into sub-patches. Divisions can be based parcels, catchments, blocks, hexagons, or any other areal unit that makes sense. Each sub-patch contains the following attributes:
- Size
- Patch to which the sub-patch belongs
- Mean distance to edge
Patch sub-network
A patch sub-network includes areas within which individuals can successfully travel between patches.
- Total habitat area
- Number of patches
