Reading the figures panel

Pixel counts and analyzed area

Every figure in the panel — and the per-layer "Area (acres)" column — is computed from a list of pixel values that WyldFire extracts from the COG for your AOI. That list is the foundation everything else builds on, and understanding what does and doesn't make it into the list is the difference between reading the figures correctly and reading them wrong.

How the count is built

For every layer, WyldFire rasterizes your AOI polygon onto the COG's own grid, then walks each pixel inside the polygon. A pixel is included in the analysis if it has a real value, and excluded if the COG marks it as NoData for that layer. The result is the per-layer pixel count, multiplied by the pixel's ground area (~900 m² for 30 m layers — see 30 m pixel in the glossary) to produce the acreage you see in the figures panel.

Analyzed area vs. geographic area

The acreage shown in the figures panel is the area where the selected layer has data, not the geodesic area of your AOI polygon. For most Wyoming AOIs the two numbers are close but not identical.

A Platte County selection, for example, shows roughly 1.06 million acres in the figures panel, while the county's actual geographic area is closer to 1.33 million acres. A gap like that has a few possible contributors mixing together:

• NoData pixels within the layer's coverage — places where the upstream product had no measurement. These are excluded from the analysis entirely.
• Polygon-vs-pixel edge alignment when the AOI is rasterized to the layer's 30 m grid. Pixels whose centers fall outside the polygon are dropped, which trims a thin strip around the perimeter.
• Boundary-feature shape — the polygon stored in our boundary layer can be a slightly simpler or different shape than the cartographic county outline you'd see on a map.

The exact mix varies by AOI. The takeaway: read the figures-panel acreage as "area over which this layer's statistics are meaningful," not "area of the polygon." For the geographic area of a polygon, use the boundary attributes from the source GIS layer (or a GIS tool's area calculator) instead.

Acreage is the same across every layer

You'll notice the acreage reported in the figures panel doesn't change as you switch between layers, even though the underlying sources (wildfire, community, vegetation) are different programs with different upstream pipelines. That's expected: every COG in WyldFire was clipped to the same Wyoming+24 km extent during preprocessing, and each upstream source covers Wyoming densely enough that NoData only shows up at the shared periphery — well outside any AOI you'd typically draw in the state. The pixel-by-pixel NoData check still runs for every layer; it just happens not to find anything different to exclude. Net effect: the analyzed area is constant across the tabs.

Why chart percentages still add up

Bar-chart class percentages and their acreage tooltips both use the same per-layer pixel count, so they stay internally consistent. If a WHP chart shows "Very High: 12% (127,094 acres)" inside an AOI whose figures panel reports 1,059,119 acres for that layer, the math checks out: 12% × 1,059,119 ≈ 127,094. Class percentages and the headline acreage both measure the same analyzed area, even when that area is smaller than the polygon's geographic footprint.