Vegetation
One layer — Existing Vegetation Type (evt) — labels every
30 m pixel with its dominant terrestrial ecosystem. It comes from the
LANDFIRE program, an interagency mapping effort between
USGS and the USDA Forest Service, and uses a NatureServe
western-hemisphere taxonomy (roughly 2,500 ecosystem classes nationally;
about 230 appear in Wyoming). Class names and renderer colors are loaded
at runtime from a sidecar file shipped alongside the raster, so a new
LANDFIRE release lands in the viewer just by re-uploading the COG.
How WyldFire processes this layer
The LANDFIRE EVT GeoTIFF is clipped to the USGS Wyoming state boundary
plus a 24-km buffer, re-encoded as a Cloud Optimized
GeoTIFF on S3 with the aux.xml color/label sidecar
preserved, and accessed via /vsicurl/ HTTP range reads.
No scaleFactor applies — class codes are nominal integers
and have no real-world units.
Existing Vegetation Type evt
What it is
"LANDFIRE's (LF) Existing Vegetation Type (EVT-ES) represents the current distribution of the terrestrial ecological systems classification, developed by NatureServe for the western hemisphere."
Categories span tree lifeforms (Conifer, Hardwood, Conifer-Hardwood), herbaceous types (Grassland, Forbland, Shrub Steppe), developed land (Low/Medium/High Intensity, Roads, Open Space), and non-vegetated cover (Water, Barren, Snow-Ice, Agriculture).
How upstream computes it
LANDFIRE produces EVT through decision-tree models run separately for each lifeform (tree, shrub, herbaceous), trained on field reference plots and predicting from Landsat imagery, topography (elevation, slope, aspect), and biophysical gradients. Models are fit per EPA Level III Ecoregion to keep regional signatures distinct. Developed/urban classes are pulled in from the National Land Cover Database (NLCD); agricultural classes pull from USDA's Cropland Data Layer. Specifics shift between LF versions — this is the general LANDFIRE pipeline.
How WyldFire processed it
Clipped to Wyoming + 24-km buffer; COG-encoded with the
aux.xml color/label sidecar preserved so the viewer
and any QGIS user gets the same NatureServe class names and the
official color ramp; S3-hosted.
Storage vs display
Native dtype is uint16 with NatureServe class codes
(e.g. 7080 = "Inter-Mountain Basins Big Sagebrush
Shrubland"). The viewer's renderer pulls labels and colors from
aux.xml rather than hard-coding them; class lookup is
driven entirely by the sidecar. In the figures panel, EVT appears
as a categorical bar chart sorted by pixel count.
How to interpret
Class codes are nominal — they have no ordering and the numeric distance between any two codes means nothing. Compare-mode shows the per-class pixel delta between two AOIs, which is the meaningful comparison for a categorical layer (e.g. "AOI A has 1,200 more Big Sagebrush pixels than AOI B").
Caveats
"USGS EROS makes no expressed or implied warranty, including warranties of merchantability and fitness for a particular purpose, with respect to the character, function, or capabilities of the data or their appropriateness for any user's purposes."
Class labels and codes drift between LF versions; do not assume a code from one vintage maps cleanly to the same code in another vintage without checking. Pixels reflect modeled dominant cover, not field-verified composition — a pixel labeled Conifer may still contain shrub or herbaceous understory. Because the taxonomy spans the western hemisphere, some Wyoming-rare class codes are also used for ecosystems outside the state.
Year availability
2016, 2022, and 2023.
Provider & citation
LANDFIRE Program — USGS EROS / USDA FS interagency.
LANDFIRE Existing Vegetation Type (EVT) CONUS. Sioux Falls, SD: USGS EROS. Use the version-specific DOI matching the vintage you're working with — for example LANDFIRE 2022 is doi.org/10.5066/P974JF8W. See landfire.gov for the program landing page and per-version DOIs.