{
 "@context": "https://schema.org",
 "@type": "Dataset",
 "name": "Runway Watch - line of sight from the Rock of Gibraltar to the 1942-43 North Front runway",
 "description": "For every 4 m cell of land on Gibraltar, the share of the North Front runway centreline visible from 1.5 m above the ground, for the runway as built by April 1942, November 1942 and July 1943. Bare-earth model, allowing for the curve of the Earth and refraction (k = 0.13).",
 "url": "https://runwaywatch.gaborszabopoker.com/",
 "license": "https://opendatacommons.org/licenses/odbl/1-0/",
 "isAccessibleForFree": true,
 "creator": {
  "@type": "Person",
  "name": "Gabor Szabo",
  "url": "https://gaborszabopoker.com"
 },
 "spatialCoverage": {
  "@type": "Place",
  "name": "Gibraltar",
  "geo": {
   "@type": "GeoShape",
   "box": "36.102259 -5.373942 36.159219 -5.318973"
  }
 },
 "temporalCoverage": "1942-04/1943-07",
 "keywords": [
  "Gibraltar",
  "North Front",
  "RAF Gibraltar",
  "runway",
  "Operation Tracer",
  "stay-behind cave",
  "viewshed",
  "line of sight",
  "Second World War",
  "EPSG:25830"
 ],
 "distribution": [
  {
   "@type": "DataDownload",
   "name": "Runway stages and target points",
   "encodingFormat": "application/json",
   "contentUrl": "https://runwaywatch.gaborszabopoker.com/data/runway.json"
  },
  {
   "@type": "DataDownload",
   "name": "View map: R = Apr 1942, G = Nov 1942, B = Jul 1943, value/255 = share of the runway seen",
   "encodingFormat": "image/png",
   "contentUrl": "https://runwaywatch.gaborszabopoker.com/data/viewshed.png"
  },
  {
   "@type": "DataDownload",
   "name": "Georeferencing metadata",
   "encodingFormat": "application/json",
   "contentUrl": "https://runwaywatch.gaborszabopoker.com/data/meta.json"
  }
 ],
 "sources": [
  {
   "name": "HM Government of Gibraltar geoportal",
   "url": "https://www.geoportal.gov.gi/",
   "provides": "terrain model, about 21 percent of the merged grid"
  },
  {
   "name": "Spanish IGN PNOA-LiDAR (MDT 5 m)",
   "url": "https://pnoa.ign.es/",
   "licence": "CC BY 4.0 scne.es",
   "provides": "elevation, about 70 percent of the merged grid"
  },
  {
   "name": "Copernicus DEM GLO-30",
   "url": "https://dataspace.copernicus.eu/explore-data/data-collections/copernicus-contributing-missions/collections-description/COP-DEM",
   "licence": "(c) DLR e.V. 2010-2014 and (c) Airbus Defence and Space GmbH 2014-2018, provided under COPERNICUS by the European Union and ESA",
   "provides": "elevation where the others have gaps, about 10 percent of the merged grid"
  },
  {
   "name": "OpenStreetMap",
   "url": "https://www.openstreetmap.org/",
   "licence": "ODbL",
   "provides": "today's runway centreline"
  },
  {
   "name": "Wikipedia: Gibraltar International Airport",
   "url": "https://en.wikipedia.org/wiki/Gibraltar_International_Airport",
   "provides": "runway history"
  },
  {
   "name": "Wikipedia: RAF Gibraltar",
   "url": "https://en.wikipedia.org/wiki/RAF_Gibraltar",
   "provides": "wartime runway extensions"
  },
  {
   "name": "Royal Navy Research Archive: North Front",
   "url": "https://www.royalnavyresearch.org.uk/FAQ-Bases/North_Front.htm",
   "provides": "runway lengths by date"
  },
  {
   "name": "HM Government of Gibraltar press release 199/2018",
   "url": "https://www.gibraltar.gov.gi/new/sites/default/files/press/2018/Press%20Releases/199-2018.pdf",
   "provides": "Operation Tracer cave: size and elevation"
  }
 ],
 "honestLimits": [
  "Today's bare ground: buildings, trees and wartime structures are not in the model, so the real 1942 view in the town and on the lower slopes was often worse than shown.",
  "The east end of the runway is taken as fixed at today's east end and each stage is measured west from it; the stage ends are approximate.",
  "Seen means a clear straight line from 1.5 m above the ground to 1 m above the runway; haze and distance are not modelled.",
  "2,996 of 3,000 random checks against an exact sightline test agreed."
 ]
}