Use turf-buffer without units and projections

packages/turf-buffer/README.md

@@ -4,7 +4,7 @@
 
 ## buffer
 
-Calculates a buffer for input features for a given radius. Units supported are miles, kilometers, and degrees.
+Calculates a buffer for input features for a given radius. Units supported are miles, kilometers, degrees, and none.
 
 When using a negative radius, the resulting geometry may be invalid if
 it's too small compared to the radius magnitude. If the input is a

packages/turf-buffer/index.js

@@ -13,7 +13,7 @@ import {
 const { BufferOp, GeoJSONReader, GeoJSONWriter } = jsts;
 
 /**
- * Calculates a buffer for input features for a given radius. Units supported are miles, kilometers, and degrees.
+ * Calculates a buffer for input features for a given radius. Units supported are miles, kilometers, degrees, and none.
  *
  * When using a negative radius, the resulting geometry may be invalid if
  * it's too small compared to the radius magnitude. If the input is a
@@ -87,6 +87,7 @@ function buffer(geojson, radius, options) {
 function bufferFeature(geojson, radius, units, steps) {
   var properties = geojson.properties || {};
   var geometry = geojson.type === "Feature" ? geojson.geometry : geojson;
+  var isUnitless = units === "none";
 
   // Geometry Types faster than jsts
   if (geometry.type === "GeometryCollection") {
@@ -100,15 +101,20 @@ function bufferFeature(geojson, radius, units, steps) {
 
   // Project GeoJSON to Azimuthal Equidistant projection (convert to Meters)
   var projection = defineProjection(geometry);
+  var projectedCoords = isUnitless
+    ? geometry.coordinates
+    : projectCoords(geometry.coordinates, projection);
   var projected = {
     type: geometry.type,
-    coordinates: projectCoords(geometry.coordinates, projection),
+    coordinates: projectedCoords,
   };
 
   // JSTS buffer operation
   var reader = new GeoJSONReader();
   var geom = reader.read(projected);
-  var distance = radiansToLength(lengthToRadians(radius, units), "meters");
+  var distance = isUnitless
+    ? radius
+    : radiansToLength(lengthToRadians(radius, units), "meters");
   var buffered = BufferOp.bufferOp(geom, distance, steps);
   var writer = new GeoJSONWriter();
   buffered = writer.write(buffered);
@@ -117,9 +123,12 @@ function bufferFeature(geojson, radius, units, steps) {
   if (coordsIsNaN(buffered.coordinates)) return undefined;
 
   // Unproject coordinates (convert to Degrees)
+  var unprojectedCoords = isUnitless
+    ? buffered.coordinates
+    : unprojectCoords(buffered.coordinates, projection);
   var result = {
     type: buffered.type,
-    coordinates: unprojectCoords(buffered.coordinates, projection),
+    coordinates: unprojectedCoords,
   };
 
   return feature(result, properties);

packages/turf-buffer/test.ts

@@ -182,6 +182,41 @@ test("turf-buffer - undefined return", (t) => {
   t.end();
 });
 
+test("turf-buffer - units none", (t) => {
+  const point: GeoJSON.Feature<GeoJSON.Point> = {
+    type: "Feature",
+    properties: {},
+    geometry: {
+      type: "Point",
+      coordinates: [0, 0],
+    },
+  };
+
+  const polygon: GeoJSON.Feature<GeoJSON.Polygon> = {
+    type: "Feature",
+    properties: {},
+    geometry: {
+      type: "Polygon",
+      coordinates: [
+        [
+          [+1, +0],
+          [+0, -1],
+          [-1, -0],
+          [-0, +1],
+          [+1, +0],
+        ],
+      ],
+    },
+  };
+
+  t.deepEqual(
+    truncate(buffer(point, 1, { units: "none", steps: 1 })),
+    polygon,
+    "unitless geometry should not be projected"
+  );
+  t.end();
+});
+
 function colorize(feature, color) {
   color = color || "#F00";
   if (feature.properties) {

packages/turf-helpers/index.ts

@@ -37,9 +37,10 @@ export type Units =
   | "yards"
   | "feet"
   | "radians"
-  | "degrees";
+  | "degrees"
+  | "none";
 export type AreaUnits =
-  | Exclude<Units, "radians" | "degrees">
+  | Exclude<Units, "radians" | "degrees" | "none">
   | "acres"
   | "hectares";
 export type Grid = "point" | "square" | "hex" | "triangle";
@@ -87,6 +88,7 @@ export const factors: Record<Units, number> = {
   nauticalmiles: earthRadius / 1852,
   radians: 1,
   yards: earthRadius * 1.0936,
+  none: NaN,
 };
 
 /**