2e:null 2f:["$","title",null,{"children":"Forest Change Detection preprocessing | Jakub Hampl | Observable"}] 34:T56f,computeIntersections = async function*(geojson) { const bar = progress({invalidation, color: 'green'}); yield bar; const removeIndices = (arr, indices) => { let newArr =[]; let nextIndex = indices.shift(); for (let i = 0; i < arr.length; i++) { if (i === nextIndex) { nextIndex = indices.shift(); } else { newArr.push(arr[i]); } } return newArr; } const intersect = (a, b) => { const abox = turf.bbox(a); const bbox = turf.bbox(b); if ((abox[0] <= bbox[2]) && (abox[2] >= bbox[0]) && (abox[1] <= bbox[3]) && (abox[3] >= bbox[1])) { return !turf.booleanDisjoint(a, b); } else { return false; } } let features = turf.flatten(geojson).features; let results = []; let counter = 0; let total = features.length; while (features.length > 0) { let feature = features.pop(); let overlapped = []; let overlappedIndices = []; for (let i = 0; i < features.length; i++) { let feat = features[i]; if (intersect(feat, feature)) { overlappedIndices.push(i); overlapped.push(feat); } } results.push([feature, ...overlapped]); features = removeIndices(features, overlappedIndices); counter += 1 + overlappedIndices.length; await bar.progress(counter, total); } bar.resolve(results); return results; }35:[] 32:{"id":"63739e259bd14316","slug":"forest-change-detection-preprocessing","title":"Forest Change Detection preprocessing","thumbnail":"c3045a819106cd2c843b803af04e9e33f6d86f7a9798872aac54622814786698","access_level":"public","create_time":"$D2019-05-21T10:58:37.315Z","update_time":"$D2019-07-05T08:48:46.785Z","view_time":null,"first_public_time":"$D2019-07-05T08:22:42.628Z","has_unpublished_edits":null,"fork":false,"stars":0,"starred":false,"owner":{"type":"team","id":"a2f700b6ce27b844","login":"gampleman","name":"Jakub Hampl","avatar_url":"https://avatars-next.observableusercontent.com/6ee048ed02abfd79e76f2f9dd7c7e8658c47b116d846f2f9ca8814ecdde18ffc","tier":"starter_2024"},"version":237,"publish_version":237,"role":null,"authored":false,"authors":[{"type":"individual","id":"34d15c3b1cc754ed","login":"gampleman","name":"Jakub Hampl","avatar_url":"https://avatars-next.observableusercontent.com/6ee048ed02abfd79e76f2f9dd7c7e8658c47b116d846f2f9ca8814ecdde18ffc","tier":null}],"members":[{"type":"individual","id":"34d15c3b1cc754ed","login":"gampleman","name":"Jakub Hampl","avatar_url":"https://avatars-next.observableusercontent.com/6ee048ed02abfd79e76f2f9dd7c7e8658c47b116d846f2f9ca8814ecdde18ffc","tier":null,"role":"editor"}],"comments":[],"custom_thumbnail":false,"trashed":false,"lapsed":null,"subscribed":null,"forks":0,"collection":null,"type":"notebook","body":{"title":"Forest Change Detection preprocessing","cells":[{"id":0,"value":"md`# Forest Change Detection preprocessing`","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":4,"value":"import { fetchGeoJSON, showGeoJSON } from '@gampleman/fetch-geojson'","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":6,"value":"viewof data = fetchGeoJSON('https://gist.githack.com/gampleman/f8c1696292edc459f14e47ecbed3e18e/raw/522f54865cf31fe2ce88dc4e8612b9c52462eeeb/Hansen_GFC-2018-v1.6_lossyear_cropped_2016-2018.geojson')","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":9,"value":"turf = require('@turf/turf')","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":222,"value":"rbush = require('rbush')","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":224,"value":"withBBoxes = data.features.map(feat => {\n const [minX, minY, maxX, maxY] = turf.bbox(feat);\n return {...feat, minX, minY, maxX, maxY};\n});","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":226,"value":"rtree = {\n const tree = new rbush();\n tree.load(withBBoxes);\n return tree;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":205,"value":"turfPointGrid = require('https://bundle.run/@turf/point-grid@6.0.1')","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":12,"value":"import {mapboxgl} from \"@tmcw/using-mapbox-gl-js\"","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":15,"value":"memorySizeOf = function (obj) {\n\n\n function sizeOf(obj) {\n return lengthInUtf8Bytes(JSON.stringify(obj));\n };\n \n function lengthInUtf8Bytes(str) {\n // Matches only the 10.. bytes that are non-initial characters in a multi-byte sequence.\n var m = encodeURIComponent(str).match(/%[89ABab]/g);\n return str.length + (m ? m.length : 0);\n }\n\n function formatByteSize(bytes) {\n if(bytes < 1024) return bytes + \" bytes\";\n else if(bytes < 1048576) return(bytes / 1024).toFixed(3) + \" KiB\";\n else if(bytes < 1073741824) return(bytes / 1048576).toFixed(3) + \" MiB\";\n else return(bytes / 1073741824).toFixed(3) + \" GiB\";\n };\n\n return formatByteSize(sizeOf(obj));\n};","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":18,"value":"dataSize = memorySizeOf(data)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":21,"value":"buffered = turf.buffer(data, 15, {units: 'meters'})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":50,"value":"memorySizeOf(buffered)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":44,"value":"simplified = turf.simplify(data, {tolerance: 0.0001, highQuality: true})","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":52,"value":"memorySizeOf(simplified)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":79,"value":"viewof intersections = []//computeIntersections(simplified)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":90,"value":"// viewof joined1 = showGeoJSON(turf.featureCollection(intersections.map(feats => {\n// if (feats.length === 1) {\n// return feats[0];\n// } else {\n// return turf.union(...feats);\n// }\n// })));","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":92,"value":"// memorySizeOf(joined1)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":127,"value":"mutable processed = simplified","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":98,"value":"viewof iteration = {\n return processed\n console.log(processed)\n const intersections = await computeIntersections(processed);\n const intersectionsResult = yield* intersections;\n const result = turf.featureCollection(intersectionsResult.map(feats => {\n if (feats.length === 1) {\n return feats[0];\n } else {\n return turf.union(...feats);\n }\n}));\n const container = html`

`;\n container.appendChild(html`

${memorySizeOf(result)}

`);\n const button = html``;\n button.addEventListener('click', () => {\n mutable processed = result;\n });\n container.appendChild(button);\n container.value = result;\n yield container;\n}","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":165,"value":"showGeoJSON(iteration)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":185,"value":"bbox = turf.bbox(simplified).map(v => Math.ceil(v * 1000) / 1000)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":196,"value":"combined = turf.combine(simplified)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":169,"value":"finalPolygons = turf.featureCollection(iteration.features.map(feat => ({type: feat.type, geometry: feat.geometry})))","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":176,"value":"grid = {\n const [minX, minY, maxX, maxY] = bbox.map(i => Math.round(i * 1000));\n const squareSize = 0.0005;\n const results = {};\n for(let latInt = minY; latInt <= maxY; latInt++) {\n for(let lngInt = minX; lngInt <= maxX; lngInt++) {\n const lat = latInt / 1000;\n const lng = lngInt / 1000;\n const queryBBox = {\n minX: lng - squareSize,\n minY: lat - squareSize,\n maxX: lng + squareSize,\n maxY: lat + squareSize\n };\n const candidates = rtree.search(queryBBox);\n if (candidates.length > 0) {\n const queryPoly = turf.bboxPolygon([queryBBox.minX, queryBBox.minY, queryBBox.maxX, queryBBox.maxY]);\n if (candidates.some(cand => !turf.booleanDisjoint(queryPoly, cand))) {\n if (!results[latInt]) {\n results[latInt] = [];\n }\n results[latInt].push(lngInt)\n }\n }\n }\n }\n return results;\n}","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":219,"value":"JSON.stringify(compactGrid)","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":62,"value":"$34","pinned":false,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"},{"id":71,"value":"import {progress} from \"@mootari/displaying-progress\";","pinned":true,"hidden":false,"mode":"ojs","author":"$undefined","summary":"$undefined","output":"$undefined","database":"$undefined"}],"files":"$W35","stdlib":"1","titling":"auto"}} 33:"$32:body"