function normalizeWinding(features) {
return rewind({ ...features }, true);
}
function featureFilterFeatures(
geo,
allowedFeatures = [
"Point",
"LineString",
"Polygon",
"MultiPoint",
"MultiLineString",
"MultiPolygon"
]
) {
const polys = featureFilter(geo, (f) =>
allowedFeatures.includes(turf.getType(f))
);
return { ...geo, features: polys };
}
function featureRemoveNonPolygonFeatures(geo) {
const polys = featureFilter(geo, (f) =>
["Polygon", "MultiPolygon"].includes(turf.getType(f))
);
return { ...geo, features: polys };
}
function featureMap(geo, fn = (d) => d) {
return turf.featureReduce(geo, (acc, curr, index) => [...acc, fn(curr, index, geo)], []);
}
function featureFilter(geo, fn = (d) => d) {
return turf.featureReduce(
geo,
(acc, curr, index) => {
if (Boolean(fn(curr, index, geo))) {
return [...acc, curr];
}
return acc;
},
[]
);
}
function featureGroupBy(geo, fn = (k) => k) {
const obj = turf.featureReduce(
geo,
(acc, curr, index) => {
const key = fn(curr) || null;
return { ...acc, [key]: [...(acc[key] || []), curr] };
},
{}
);
return new Map(Object.entries(obj));
}
function createFeatureCollection(geos) {
const features = geos.flatMap(
(f) => (Array.isArray(f.features) ? f.features : [f]) // Assume it is a single feature
);
return geotoolbox.featurecollection(features)
}
function previewGeojson(arr) {
if (Array.isArray(arr)) {
return bertin.quickdraw(arr.map(normalizeWinding))
}
return bertin.quickdraw(normalizeWinding(arr))
}
point = turf.point
geotoolbox = require("geotoolbox@1.9.2/dist/index.min.js")
bertin = import('https://cdn.skypack.dev/bertin@1.5.9?min')
One platform to build and deploy the best data apps
Experiment and prototype by building visualizations in live JavaScript notebooks. Collaborate with your team and decide which concepts to build out.
Use Observable Framework to build data apps locally. Use data loaders to build in any language or library, including Python, SQL, and R.
Seamlessly deploy to Observable. Test before you ship, use automatic deploy-on-commit, and ensure your projects are always up-to-date.