{ "id": "ponderosa-canyon", "name": "Ponderosa Canyon rim", "group": "Higher southern forests", "center": [ -112.2603, 37.5031 ], "width_m": 768, "surface_method": "classified-ground", "source_ids": [ "nps-ponderosa", "nps-pois", "gnis" ], "place_ids": [ "ponderosa-canyon" ], "theme": "Elevation changes the setting", "question": "Where is the ground beneath the forest?", "interaction": "returns", "view_yaw": 1.15, "view_pitch": 1.12, "schema": 1, "kind": "landscape-study", "checked_at": "2026-10-02", "geometry_status": "Derived from source-classified ground returns; terrain study, not a closed rock scan", "coordinate_system": { "native_horizontal": "NAD83(2011) / UTM 12N (EPSG:6341)", "ept_horizontal": "WGS84 Pseudo-Mercator (EPSG:3857)", "export_horizontal": "WGS84 / UTM 12N (EPSG:32612)", "vertical": "NAVD88, Geoid12B; source heights retained", "units": "metres", "axes": "x east, y up from base_m, z south", "base_m": 2410, "center_utm": [ 388604.2477561373, 4151431.210372027 ], "bounds_utm": [ 388220.2477561373, 4151047.210372027, 388988.2477561373, 4151815.210372027 ], "bounds_wgs84": [ -112.26470188088783, 37.49959317067899, -112.2558985198461, 37.50660667907206 ], "vertical_exaggeration": 1, "transform_note": "EPT projection transformed with pyproj; no claim of survey-grade datum alignment. Centimetre export quantization is not source accuracy." }, "statistics": { "returns_in_crop": 20487525, "density_returns_per_m2": 34.735, "ground_returns": 5349782, "retained_returns": 5349782, "vegetation_candidate_returns": 6591598, "excluded_noise_or_other": 16266, "directly_observed_node_fraction": 0.9351405370693356, "interpolated_node_fraction": 0.02955135293290623, "unsupported_node_fraction": 0.035308109997758096, "isolated_high_cells_repaired": 3, "source_gap_node_fraction": 0.019656570492725206, "cliff_or_small_patch_omission_fraction": 0.015651539505032886, "maximum_3x3_relief_m": 12.0, "minimum_connected_patch_m2": 100.0, "maximum_nearest_fill_m": 3.0, "cell_m": 1.5, "distance_reference": "Distance between grid-node centers, not exact source-point XY.", "maximum_grid_bin_offset_m": 1.0606601717798212, "maximum_source_xy_distance_bound_m": 4.060660171779821, "source_heights_m": [ 2425.6201171875, 2766.449951171875 ], "surface_heights_m": [ 2426.06005859375, 2750.85009765625 ], "intensity_display_percentiles": [ 2176.0, 16912.0 ], "vertical_surfaces": "Abrupt interpolated cliff nodes are omitted; directly sampled bins are retained. Connecting top-surface samples still does not measure a wall, undercut, window or unseen interior.", "surface_method": "classified-ground" }, "levels": [ { "file": "small.glb.gz", "bytes": 420164, "uncompressed_bytes": 1093756, "sha256": "36bfac996fc23d44444ef5031846b0fdb5f2aa20f6962c63660714372b7ca51d", "id": "small", "vertices": 16641, "triangles": 29974, "grid_nodes": 129, "spacing_m": 6.0, "degenerate_triangles": 0, "downward_triangles": 0 }, { "file": "balanced.glb.gz", "bytes": 1610186, "uncompressed_bytes": 4384728, "sha256": "1d1914ef58d92843e9db92bc08aef8d3679cb225222226895841d30e09c71d6b", "id": "balanced", "vertices": 66049, "triangles": 123058, "grid_nodes": 257, "spacing_m": 3.0, "degenerate_triangles": 0, "downward_triangles": 0 }, { "file": "detailed.glb.gz", "bytes": 6313997, "uncompressed_bytes": 17568444, "sha256": "47157b0f8fc5d317700e9e3804b708ebe7a9bf21e441a94cf1ca68ad856bb953", "id": "detailed", "vertices": 263169, "triangles": 498926, "grid_nodes": 513, "spacing_m": 1.5, "degenerate_triangles": 0, "downward_triangles": 0 } ], "returns": { "file": "returns.glb.gz", "bytes": 1249488, "uncompressed_bytes": 2881236, "sha256": "d6161bbf47c3e4af85fea332a718118a9b0c5a04c51aaa47a6585c8ef1a7913a", "count": 120000, "sampling": "fixed seed 20261002, uniform without replacement from valid crop returns" }, "profiles": "profiles.json.gz", "coverage": { "image": "coverage.webp", "data": "coverage.json.gz", "nodes": 513, "orientation": "north up; west left" }, "camera": { "yaw": 1.15, "pitch": 1.12, "distance_m": 1536.0, "target": [ 0, 257.25, 0 ], "limits": { "minimum_distance_widths": 1.35, "maximum_distance_widths": 4, "minimum_pitch_radians": 1.0, "maximum_pitch_radians": 1.55 }, "scope": "Above-terrain observation only; no ground-level camera or visitor-viewpoint equivalence." }, "bounds_local": [ [ -384.0, 16.06005859375, -384.0 ], [ 384.0, 340.85009765625, 384.0 ] ], "source_dataset": { "id": "USGS_LPC_UT_Southern_QL1_2018_LAS_2019", "acquired": "2018-04-27 / 2018-07-29 project interval", "published": "2019-06-03", "url": "https://registry.opendata.aws/usgs-lidar/", "license": "US Government Public Domain", "credit": "Map services and data available from U.S. Geological Survey, National Geospatial Program." }, "processing": { "mesh": "Source class 2 ground only. Highest retained return per nearest grid node; nearest interpolation up to 3 m; isolated spikes exceeding all 8 neighbors by 6 m lowered to neighbor maximum. Interpolated nodes with more than 12 m relief across a 3x3 neighborhood and connected patches smaller than 100 m² are omitted. Directly sampled ground bins otherwise remain, including steep rims. Original returns are unchanged. No morphological closing.", "vegetation": "Source classes 3/4/5 plus low-intensity multiple echoes and low-intensity raised returns over nearby gentle classified ground are excluded. This is an imperfect heuristic, not a species/rock classifier.", "lighting": "Normals and static 12-direction terrain occlusion are derived; material color, studio lighting and display category colors are illustrative.", "detail": "Three nested node grids; no-data cells omitted at every LOD; low LOD can omit extra edge triangles to preserve holes." }, "limitations": [ "Hidden rock surfaces, undercuts and windows are not reconstructed.", "Abrupt interpolated cliff nodes are omitted; connections between directly sampled bins are derived facets, not measured wall surfaces.", "Ground classification can omit standing rock or retain classification errors; inspect the return view.", "NAIP is overhead imagery from a different year; it cannot supply photographic detail on vertical faces.", "The cut boundary is an editorial crop; there is no modeled geology beneath it.", "No route, current condition, erosion rate or collapse forecast is inferred." ], "posters": { "large": "poster.webp", "small": "poster-small.webp", "material": "aerial", "geometry_year": 2018, "imagery_year": 2024, "kind": "actual model render, not a ground photograph" }, "quality_status": "qualified-ground-terrain-with-visible-omissions", "editorial": { "lede": "A forest can hide the slope without changing the height of the ground.", "body": "Ponderosa Canyon is named for trees below the overlook. NPS contrasts these with the mixed conifer forest at the higher rim. Switch between ground, aerial color and source returns to distinguish the elevation of the land from vegetation above it.", "lesson": "The profile samples the ground class from the 2018 survey. The return sample also contains echoes from higher surfaces, and the 2024 aerial image records the canopy. These layers describe different things at different dates.", "limit": "The point cloud does not identify tree species. Aerial color is not a vegetation inventory, and ground filtering can omit standing formations. The full canyon and distant plateau are outside this crop.", "caption": "The ground beneath the Ponderosa Canyon rim, presented without modeled tree crowns.", "comparison": "The forest-zone interpretation comes from NPS. It is context for the measured relief, not a classification produced from image color." }, "sources": [ { "id": "nps-ponderosa", "title": "Ponderosa Canyon", "url": "https://www.nps.gov/places/000/ponderosa-canyon.htm", "publisher": "National Park Service", "date": null, "retrieved_at": "2026-10-02", "license": "Facts paraphrased and linked. Photograph rights recorded separately per image.", "supports": "Forest zones in relation to elevation and named overlook. Neither species nor geological contacts inferred from color." }, { "id": "nps-pois", "title": "NPS Public Points of Interest", "url": "https://mapservices.nps.gov/arcgis/rest/services/NationalDatasets/NPS_Public_POIs/FeatureServer/0", "publisher": "National Park Service", "date": "dataset records have individual dates", "retrieved_at": "2026-10-02", "license": "NPS public geospatial data; no endorsement; agency source and accuracy fields preserved", "supports": "Mapped overlook positions; Hat Shop Hoodoos Viewpoint 9513. Accuracy is unknown, scaled or >=14 m for used records. Existing travel coordinates remain unchanged; similar names with different roles are not substituted." }, { "id": "gnis", "title": "Geographic Names — Landforms", "url": "https://carto.nationalmap.gov/arcgis/rest/services/geonames/MapServer/5", "publisher": "US Geological Survey", "date": null, "retrieved_at": "2026-10-02", "license": "US Government Public Domain; USGS National Map terms", "supports": "Independent named-feature locators, including Hat Shop 1441625, Farview 1441016, Piracy 1444459 and Corral Hollow 1439972. Points do not define a feature boundary. Valley records include multiple positions, not a trail polyline." } ], "imagery": { "publisher": "USDA Farm Service Agency / FPAC", "dataset": "National Agriculture Imagery Program (NAIP), Utah 2024", "retrieved_at": "2026-10-02T09:10:40.752372+00:00", "source_pixels_m": 0.6, "export_pixels": 1280, "export_pixel_m": 0.6, "crs": "EPSG:32612", "requested_bounds": [ 388220.2477561373, 4151047.210372027, 388988.2477561373, 4151815.210372027 ], "export_extent": { "xmin": 388220.2477561373, "ymin": 4151047.210372027, "xmax": 388988.2477561373, "ymax": 4151815.210372027, "spatialReference": { "wkid": 32612, "latestWkid": 32612 } }, "flight_dates": [ "2024-07-23" ], "images": [ { "OBJECTID": 195922, "Name": "m_3711238_ne_12_060_20240723", "Category": 1, "year_ts": 2024, "ST": "UT", "QQNAME": "3711238NE060", "QQDATE": 1721692800000, "iDate_ts": 1749744257170 }, { "OBJECTID": 195956, "Name": "m_3711230_se_12_060_20240723", "Category": 1, "year_ts": 2024, "ST": "UT", "QQNAME": "3711230SE060", "QQDATE": 1721692800000, "iDate_ts": 1749744257170 } ], "catalog_url": "https://apps.geo.fpac.usda.gov/geo-imagery/rest/services/naip/conus_naip/ImageServer/query?f=json&geometry=%7B%22xmin%22%3A388220.2477561373%2C%22ymin%22%3A4151047.210372027%2C%22xmax%22%3A388988.2477561373%2C%22ymax%22%3A4151815.210372027%2C%22spatialReference%22%3A%7B%22wkid%22%3A32612%7D%7D&geometryType=esriGeometryEnvelope&inSR=32612&spatialRel=esriSpatialRelIntersects&outFields=%2A&returnGeometry=false&where=Category%3D1+AND+year_ts%3D2024", "export_url": "https://apps.geo.fpac.usda.gov/geo-imagery/rest/services/naip/conus_naip/ImageServer/exportImage?f=json&bbox=388220.2477561373%2C4151047.210372027%2C388988.2477561373%2C4151815.210372027&bboxSR=32612&imageSR=32612&size=1280%2C1280&format=png&pixelType=U8&interpolation=RSP_BilinearInterpolation&adjustAspectRatio=false&bandIds=0%2C1%2C2&mosaicRule=%7B%22mosaicMethod%22%3A%22esriMosaicLockRaster%22%2C%22lockRasterIds%22%3A%5B195922%2C195956%5D%2C%22mosaicOperation%22%3A%22MT_FIRST%22%7D", "direct_image_url": "https://apps.geo.fpac.usda.gov/geo-imagery/rest/services/naip/conus_naip/ImageServer/exportImage?f=image&bbox=388220.2477561373%2C4151047.210372027%2C388988.2477561373%2C4151815.210372027&bboxSR=32612&imageSR=32612&size=1280%2C1280&format=png&pixelType=U8&interpolation=RSP_BilinearInterpolation&adjustAspectRatio=false&bandIds=0%2C1%2C2&mosaicRule=%7B%22mosaicMethod%22%3A%22esriMosaicLockRaster%22%2C%22lockRasterIds%22%3A%5B195922%2C195956%5D%2C%22mosaicOperation%22%3A%22MT_FIRST%22%7D", "original_sha256": "3201651dff7d42025d0a3b4e4eabedba6eae378bf202f7f9e137cc26564dddb4", "license": "US Government Public Domain", "license_url": "https://catalog.data.gov/dataset/national-agriculture-imagery-program-naip-imagery", "processing": "Locked 2024 primary rasters, RGB bands 0/1/2, orthographic drape; bilinear export, WebP encoding. No invented detail.", "limitations": "Leaf-on aerial imagery draped on 2018 filtered topography; acquisition shadows, tree crowns, temporal differences and metre-scale registration error remain. Cliff faces stretch a top-down pixel; hidden walls are not photographed." }, "visual_review": { "checked_at": "2026-10-02", "views": [ "overview", "left oblique", "right oblique", "nearest allowed", "aerial", "north-up" ], "scope": "Above-terrain ground study only. Visible gaps remain; neither closed cliffs nor cap/neck fidelity is accepted.", "camera_minimum_pitch_degrees": 57.2957795, "camera_minimum_distance_widths": 1.35 } }