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Clean Up for Natural Earth GeoJSON
var fs = require("fs");
var roundPrecision = 1e6;
fs.readFile("/dev/stdin", "utf-8", function(error, input) {
var collection = JSON.parse(input);
switch (collection.type) {
case "FeatureCollection": return cleanupFeatureCollection(collection);
case "GeometryCollection": return cleanupGeometryCollection(collection);
default: throw "unknown type: " + collection.type;
}
});
function cleanupFeatureCollection(collection) {
console.log("{\"type\":\"FeatureCollection\",\"features\":[");
console.log(collection.features.map(cleanupFeature).map(stringify).join(",\n"));
console.log("]}");
}
function cleanupGeometryCollection(collection) {
console.log("{\"type\":\"GeometryCollection\",\"features\":[");
console.log(collection.features.map(cleanupGeometry).map(stringify).join(",\n"));
console.log("]}");
}
function cleanupFeature(feature) {
if (feature.properties.ISO_A3) {
if (/[A-Z]{3}/.test(feature.properties.ISO_A3)) {
feature.id = feature.properties.ISO_A3;
} else {
console.warn("ignoring invalid ISO code for " + feature.properties.NAME + ": " + feature.properties.ISO_A3);
}
} else if (feature.properties.FIPS) {
if (/[0-9]{2}/.test(feature.properties.FIPS)) {
feature.id = feature.properties.FIPS;
} else {
console.warn("ignoring invalid FIPS code for " + feature.properties.NAME + ": " + feature.properties.FIPS);
}
}
feature.properties = {name: feature.properties.NAME};
cleanupGeometry(feature.geometry);
return feature;
}
function cleanupGeometry(geometry) {
switch (geometry.type) {
case "Polygon": geometry.coordinates = roundPolygon(geometry.coordinates); break;
case "MultiPolygon": geometry.coordinates = roundMultiPolygon(geometry.coordinates); break;
case "LineString": geometry.coordinates = roundLineString(geometry.coordinates); break;
default: throw "unknown type: " + geometry.type;
}
return geometry;
}
function roundMultiPolygon(coordinates) {
return coordinates.map(roundPolygon);
}
function roundPolygon(coordinates) {
return coordinates.map(roundLineString);
}
function roundLineString(coordinates) {
return coordinates.map(roundCoordinate);
}
function roundCoordinate(coordinate) {
return coordinate.map(round);
}
function round(x) {
return Math.round(x * roundPrecision) / roundPrecision;
}
function stringify(o) {
return JSON.stringify(o);
}
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