Solar Siting Weighted Overlay (Utah)

# Platform Comparison: Weighted Overlay (Solar Siting) — Gold Spec
#
# Identify areas suitable for solar installation in central Utah
# using slope, aspect, and land cover criteria.
# Ground truth: ~9% of AOI.
#
# This spec is designed to run through both the Python backend and
# browser-wasm executor (folia bench exec -b browser-wasm).

name: weighted-overlay
version: "1.0"
description: >
  Solar siting analysis via weighted overlay.  Combine slope (<5 deg),
  south-facing aspect (135-225 deg), and non-forest/non-water land cover
  to find suitable areas in central Utah.
  Ground truth: ~9% of AOI (calibrated from GEE 2026-03-29).

settings:
  default_bbox: [-112.5, 39.5, -111.5, 40.5]
  default_crs: EPSG:4326

layers:

  # ============================================================
  # SOURCE LAYERS
  # ============================================================

  source/dem:
    uri: stac://earth-search/cop-dem-glo-30
    type: raster
    description: >
      Copernicus GLO-30 DEM (30m) for central Utah.
    params:
      bbox: [-112.5, 39.5, -111.5, 40.5]

  source/worldcover:
    uri: stac://earth-search/esa-worldcover
    type: raster
    description: >
      ESA WorldCover 2021 (10m) for central Utah.
    params:
      bbox: [-112.5, 39.5, -111.5, 40.5]

  # ============================================================
  # COMPUTE: TERRAIN CRITERIA
  # ============================================================

  compute/slope:
    type: raster
    description: >
      Slope in degrees.
    compute:
      op: terrain_slope
      inputs:
        dem: { layer: source/dem }
      params:
        units: degrees

  compute/aspect:
    type: raster
    description: >
      Aspect in degrees (0-360).
    compute:
      op: terrain_aspect
      inputs:
        dem: { layer: source/dem }

  compute/slope-ok:
    type: raster
    description: >
      Binary mask: slope < 5 degrees.
    compute:
      op: raster_threshold_mask
      inputs:
        data: { layer: compute/slope }
      params:
        threshold: 5
        operator: lt

  compute/aspect-ok:
    type: raster
    description: >
      Binary mask: south-facing aspect (135-225 degrees).
    compute:
      op: raster_calc
      inputs:
        aspect: { layer: compute/aspect }
      params:
        expression: "where((aspect >= 135) & (aspect <= 225), 1, 0)"

  # ============================================================
  # COMPUTE: LAND COVER CRITERIA
  # ============================================================

  compute/lc-ok:
    type: raster
    description: >
      Binary mask: exclude forest (10), water (80), wetland (90).
    compute:
      op: raster_calc
      inputs:
        lc: { layer: source/worldcover }
      params:
        expression: "where((lc != 10) & (lc != 80) & (lc != 90), 1, 0)"

  # ============================================================
  # COMPUTE: COMBINED SUITABILITY
  # ============================================================

  compute/suitable:
    type: raster
    description: >
      Combined suitability: all three criteria must be met.
    compute:
      op: raster_calc
      inputs:
        slope_ok: { layer: compute/slope-ok }
        aspect_ok: { layer: compute/aspect-ok }
        lc_ok: { layer: compute/lc-ok }
      params:
        expression: "slope_ok * aspect_ok * lc_ok"

  # ============================================================
  # RESULT: SUITABILITY PERCENTAGE
  # ============================================================

  result/suitable-pct:
    type: table
    description: >
      Percentage of the AOI meeting all suitability criteria.
      Ground truth: ~9%.
    compute:
      op: analysis_zonal_stats
      params:
        stats: [mean]
      inputs:
        raster: { layer: compute/suitable }