{
  "title": "LIBLICE 355 official ČÚZK terrain assets",
  "downloaded_utc": "2026-10-03",
  "center": {
    "lon": 14.8866,
    "lat": 50.0625
  },
  "horizontal_crs": "EPSG:3857",
  "vertical_datum": "Bpv (Baltic after adjustment), meters above sea level; source EPSG:8357",
  "attribution": "© ČÚZK — Ortofoto ČR and DMR 5G, CC BY 4.0. Cropped, projected and resampled.",
  "license": "https://creativecommons.org/licenses/by/4.0/",
  "license_source": "https://ags.cuzk.gov.cz/opendata/",
  "source_services": {
    "orthophoto": "https://ags.cuzk.gov.cz/arcgis1/rest/services/ORTOFOTO/MapServer",
    "height": "https://ags.cuzk.gov.cz/arcgis2/rest/services/dmr5g/ImageServer",
    "dates": "https://ags.cuzk.gov.cz/arcgis/rest/services/Metadata/MapServer"
  },
  "orientation": "North up. All raster rows run north to south; columns run west to east.",
  "world_convention": "For local east-positive x and south-positive z: x=(mercatorX-centerX)*cos(centerLat); z=(centerY-mercatorY)*cos(centerLat). y=height_Bpv_m.",
  "height_layout": "Float32 little-endian; headerless; row-major; index=row*gridSize+column; samples at geometry boundary vertices, not cell centers.",
  "projection_note": "Widths are locally scaled Mercator meters using cos(center latitude), not geodesic squares. Scale varies slightly with latitude across the 64 km extent. Heights are true source meters and require no horizontal scale multiplier.",
  "lod_note": "The service may use different terrain overviews at different requested resolutions. Near and far grids can differ by a few meters at matching coordinates; use the near grid in the center and blend elevations at the LOD transition.",
  "assets": {
    "near": {
      "ground_width_m": 8000,
      "geometry_bbox_3857": [
        1650937.7323216526,
        6450875.784505484,
        1663399.7309646402,
        6463337.78314847
      ],
      "center_3857": [
        1657168.7316431464,
        6457106.783826977
      ],
      "ground_meters_per_mercator_meter": 0.6419516025627031,
      "orthophoto": {
        "file": "liblice_near_ortho.jpg",
        "width": 4096,
        "height": 4096,
        "output_meters_per_pixel": 1.953125,
        "source_pixel_size_m": 0.125,
        "source_update_years": [
          "2025"
        ]
      },
      "height": {
        "file": "liblice_near_height.f32",
        "geotiff": "liblice_near_height.tif",
        "grid_size": 257,
        "spacing_m": 31.25,
        "source_native_pixel_size_m": 2,
        "min_m": 205.9649200439453,
        "max_m": 365.96417236328125,
        "center_m": 255.7019500732422,
        "source_metadata_years": [
          2010,
          2024
        ],
        "vertex_formula": "x=-width/2+column*spacing; z=-width/2+row*spacing; y=heights[row*size+column]",
        "image_export_extent_3857": {
          "xmin": 1650913.392480553,
          "ymin": 6450851.444664384,
          "xmax": 1663424.0708057398,
          "ymax": 6463362.12298957,
          "spatialReference": {
            "wkid": 102100,
            "latestWkid": 3857
          }
        }
      }
    },
    "far": {
      "ground_width_m": 64000,
      "geometry_bbox_3857": [
        1607320.7370711968,
        6407258.789255028,
        1707016.726215096,
        6506954.778398926
      ],
      "center_3857": [
        1657168.7316431464,
        6457106.783826977
      ],
      "ground_meters_per_mercator_meter": 0.6419516025627031,
      "orthophoto": {
        "file": "liblice_far_ortho.jpg",
        "width": 4096,
        "height": 4096,
        "output_meters_per_pixel": 15.625,
        "source_pixel_size_m": 0.125,
        "source_update_years": [
          "2024",
          "2025"
        ]
      },
      "height": {
        "file": "liblice_far_height.f32",
        "geotiff": "liblice_far_height.tif",
        "grid_size": 513,
        "spacing_m": 125.0,
        "source_native_pixel_size_m": 2,
        "min_m": 155.4907989501953,
        "max_m": 561.5340576171875,
        "center_m": 254.5859832763672,
        "source_metadata_years": [
          2010,
          2017,
          2019,
          2020,
          2022,
          2023,
          2024,
          2025
        ],
        "vertex_formula": "x=-width/2+column*spacing; z=-width/2+row*spacing; y=heights[row*size+column]",
        "image_export_extent_3857": {
          "xmin": 1607223.3777067985,
          "ymin": 6407161.429890629,
          "xmax": 1707114.0855794942,
          "ymax": 6507052.137763325,
          "spatialReference": {
            "wkid": 102100,
            "latestWkid": 3857
          }
        }
      }
    },
    "detail": {
      "ground_width_m": 2000,
      "geometry_bbox_3857": [
        1655610.981812773,
        6455549.033996603,
        1658726.4814735197,
        6458664.533657351
      ],
      "orthophoto": {
        "file": "liblice_detail_ortho.jpg",
        "width": 4096,
        "height": 4096,
        "output_meters_per_pixel": 0.48828125,
        "source_update_years": [
          "2025"
        ]
      },
      "request_url": "https://ags.cuzk.gov.cz/arcgis1/rest/services/ORTOFOTO/MapServer/export?bbox=1655610.981812773%2C6455549.033996603%2C1658726.4814735197%2C6458664.533657351&bboxSR=3857&imageSR=3857&size=4096%2C4096&f=pjson&format=jpg&transparent=false&dpi=96"
    }
  },
  "center_metadata": {
    "orthophoto_update_date": "2025-06-21",
    "orthophoto_source_sheet": "WRTO24.2025.CBRO45",
    "terrain_source_metadata_year": 2010,
    "note": "Official metadata gives update date, not necessarily flight/capture date."
  },
  "sha256": {
    "liblice_near_height.tif": "fb02fe7cbdbf0b371ef13deed4dda15d22eb3e79cf694f43f3edcd86f640b339",
    "liblice_near_height.f32": "d3f20ec1b756ce728506bdfc2b3e88f35ed198e05497fad9a4a73a6048cbfd82",
    "liblice_far_height.tif": "f37e4e6bdef131b4b7ccf16cbcc730b2edc0922877c8c01399570c561d5a1232",
    "liblice_far_height.f32": "aaf375030e26968a06a040535e46d031d2d842b24c5b45154e0fa660ea02e30a",
    "liblice_near_ortho.jpg": "a0d1fcac43864f1068af2fe9cb434e9b666ccd16386a33818f92c92972862c2d",
    "liblice_far_ortho.jpg": "c83767275aa7176284a488a7621806d08868a37871e765ff669f3af5cb20b24a",
    "liblice_detail_ortho.jpg": "4a31cf42abe91fcbba0d966bff834fcd69f5a694359e5bc68a3da04fb7356298"
  },
  "mobile_note": "All three orthophoto levels also have 2048-square mobile variants, Lanczos resampling, JPEG quality 92."
}