increased precision

DanielJDufour · Dec 28, 2021 · 211e981 · 211e981
1 parent 6e28e39
commit 211e981
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Showing 5 changed files with 126 additions and 53 deletions.
diff --git a/package.json b/package.json
@@ -12,7 +12,7 @@
   ],
   "scripts": {
     "build": "cp ./src/geo-extent.js ./dist/geo-extent.mjs && npx babel ./src/geo-extent.js --out-file ./dist/geo-extent.cjs --plugins=@babel/plugin-transform-modules-commonjs",
-    "format": "npx prettier --arrow-parens=avoid --print-width=120 --trailing-comma=none --write src/*.js test/*.js",
+    "format": "npx prettier --arrow-parens=avoid --print-width=120 --trailing-comma=none --write src/*.js test/*.js test/*.mjs",
     "prepublishOnly": "npm run format",
     "test": "for f in ./test/*; do node $f; done",
     "test:html": "snowpack dev --polyfill-node"
@@ -53,6 +53,7 @@
     "snowpack": "^3.8.8"
   },
   "dependencies": {
+    "big.js": "^6.1.1",
     "get-epsg-code": "^0.0.7",
     "reproject-bbox": "^0.2.0"
   }

diff --git a/src/geo-extent.js b/src/geo-extent.js
@@ -2,10 +2,11 @@
  * TO DO:
  * add support for GeoJSON and need to check projection of GeoJSON
  */
+import Big from "big.js";
 import getEPSGCode from "get-epsg-code";
 import reprojectBoundingBox from "reproject-bbox";
 
-const avg = (a, b) => (a + b) / 2;
+const avg = (a, b) => Big(a).plus(Big(b)).div(Big(2));
 const isAry = o => Array.isArray(o);
 const isDef = o => o !== undefined && o !== null && o !== "";
 const isFunc = o => typeof o === "function";
@@ -32,6 +33,7 @@ const hasObjs = (o, ks) => ks.every(k => hasObj(o, k));
 const hasKey = (o, k) => isObj(o) && o[k] !== undefined && o[k] !== null;
 const hasKeys = (o, ks) => ks.every(k => hasKey(o, k));
 const allNums = ary => isAry(ary) && ary.every(isNum);
+const allStrs = ary => isAry(ary) && ary.every(isStr);
 const getConstructor = o => (typeof obj === "object" && typeof obj.constructor === "function") || undefined;
 const normalize = srs => {
   if (!srs) return srs;
@@ -74,6 +76,7 @@ export class GeoExtent {
     this.srs = normalize(srs);
 
     let xmin, xmax, ymin, ymax;
+    let xmin_str, xmax_str, ymin_str, ymax_str;
     if (getConstructor(o) === this.constructor) {
       ({ xmin, xmax, ymin, ymax } = o);
       if (isDef(o.srs)) {
@@ -82,6 +85,9 @@ export class GeoExtent {
     }
     if (isAry(o) && o.length === 4 && allNums(o)) {
       [xmin, ymin, xmax, ymax] = o;
+    } else if (isAry(o) && o.length === 4 && allStrs(o)) {
+      [xmin_str, ymin_str, xmax_str, ymax_str] = o;
+      [xmin, ymin, xmax, ymax] = o.map(str => Number(str));
     } else if (isAry(o) && o.length === 2 && o.every(isAry) && o.every(o => o.length === 2 && allNums(o))) {
       [[ymin, xmin], [ymax, xmax]] = o;
     } else if (isLeafletLatLngBounds(o)) {
@@ -139,11 +145,21 @@ export class GeoExtent {
     }
 
     this.xmin = xmin;
+    this.xmin_str = xmin_str || xmin.toString();
     this.ymin = ymin;
+    this.ymin_str = ymin_str || ymin.toString();
     this.xmax = xmax;
+    this.xmax_str = xmax_str || xmax.toString();
     this.ymax = ymax;
-    this.width = xmax - xmin;
-    this.height = ymax - ymin;
+    this.ymax_str = ymax_str || ymax.toString();
+
+    const width = Big(this.xmax_str).minus(this.xmin_str);
+    this.width = width.toNumber();
+    this.width_str = width.toString();
+
+    const height = Big(this.ymax_str).minus(this.ymin_str);
+    this.height = height.toNumber();
+    this.height_str = height.toString();
 
     // corners
     this.bottomLeft = { x: xmin, y: ymin };
@@ -156,11 +172,26 @@ export class GeoExtent {
       [this.ymax, this.xmax]
     ];
 
-    this.area = this.width * this.height;
-    this.perimeter = 2 * this.width + 2 * this.height;
+    const area = Big(width).times(height);
+    this.area = area.toNumber();
+    this.area_str = area.toString();
+
+    const perimeter = width.times(2).plus(height.times(2));
+    this.perimeter = perimeter.toNumber();
+    this.perimeter_str = perimeter.toString();
+
     this.bbox = [xmin, ymin, xmax, ymax];
-    this.center = { x: avg(xmin, xmax), y: avg(ymin, ymax) };
-    this.str = this.bbox.join(",");
+    this.bbox_str = [this.xmin_str, this.ymin_str, this.xmax_str, this.ymax_str];
+
+    const center = {
+      x: avg(xmin_str || xmin, xmax_str || xmax),
+      y: avg(ymin_str || ymin, ymax_str || ymax)
+    };
+
+    this.center = { x: center.x.toNumber(), y: center.y.toNumber() };
+    this.center_str = { x: center.x.toString(), y: center.y.toString() };
+
+    this.str = this.bbox_str.join(",");
   }
 
   _pre(_this, _other) {

diff --git a/test/test.combine.mjs b/test/test.combine.mjs
@@ -7,4 +7,4 @@ test("combine southern and northern hemisphers", ({ eq }) => {
   const combined = new GeoExtent({ xmin: -180, ymin: -90, xmax: 180, ymax: 90, srs: 4326 });
   eq(ne.combine(sw), combined);
   eq(sw.combine(ne), combined);
-});
+});
diff --git a/test/test.mjs b/test/test.mjs
@@ -10,34 +10,49 @@ const CENTER = { x: (XMIN + XMAX) / 2, y: (YMIN + YMAX) / 2 };
 const WIDTH = XMAX - XMIN;
 const HEIGHT = YMAX - YMIN;
 const AREA = WIDTH * HEIGHT;
-const TWO_CORNER_BOUNDS = [ [YMIN, XMIN], [YMAX, XMAX] ];
+const PERIMETER = 2 * WIDTH + 2 * HEIGHT;
+const TWO_CORNER_BOUNDS = [
+  [YMIN, XMIN],
+  [YMAX, XMAX]
+];
 const NORTHERN_HEMISPHERE = [-180, 0, 180, 90];
 const SOUTHERN_HEMISPHERE = [-180, -90, 180, 0];
 const WESTERN_HEMISPHERE = [-180, -90, 0, 90];
 const EASTERN_HEMISPHERE = [0, -90, 180, 90];
 const NORTH_WEST_QUARTER_SPHERE = [-180, 0, 0, 90];
+const str = n => n.toString();
 
 const AS_OBJ_RESULT = {
-  srs: 'EPSG:4326',
-  area: AREA,
-  perimeter: 2 * WIDTH + 2 * HEIGHT,
-  bbox: BBOX,
-  center: CENTER,
-  xmin: XMIN,
-  ymin: YMIN,
-  xmax: XMAX,
-  ymax: YMAX,
-  width: WIDTH,
-  height: HEIGHT,
-  bottomLeft: { x: XMIN, y: YMIN },
-  bottomRight: { x: XMAX, y: YMIN },
-  topLeft: { x: XMIN, y: YMAX },
-  topRight: { x : XMAX, y: YMAX },
-  str: BBOX.join(","),
+  srs: "EPSG:4326",
+  xmin: -72,
+  xmin_str: "-72",
+  ymin: -47,
+  ymin_str: "-47",
+  xmax: 21,
+  xmax_str: "21",
+  ymax: 74,
+  ymax_str: "74",
+  width: 93,
+  width_str: "93",
+  height: 121,
+  height_str: "121",
+  bottomLeft: { x: -72, y: -47 },
+  bottomRight: { x: 21, y: -47 },
+  topLeft: { x: -72, y: 74 },
+  topRight: { x: 21, y: 74 },
   leafletBounds: [
-    [YMIN, XMIN],
-    [YMAX, XMAX]
-  ]
+    [-47, -72],
+    [74, 21]
+  ],
+  area: 11253,
+  area_str: "11253",
+  perimeter: 428,
+  perimeter_str: "428",
+  bbox: [-72, -47, 21, 74],
+  bbox_str: ["-72", "-47", "21", "74"],
+  center: { x: -25.5, y: 13.5 },
+  center_str: { x: "-25.5", y: "13.5" },
+  str: "-72,-47,21,74"
 };
 // console.log(AS_OBJ_RESULT);
 
@@ -60,41 +75,46 @@ test("create from bbox in 4326", ({ eq }) => {
 
 test("create from points", ({ eq }) => {
   const EXPECTED_EXTENT_FOR_PT = {
-    srs: 'EPSG:4326',
+    srs: "EPSG:4326",
     xmin: 147,
+    xmin_str: "147",
     ymin: -18,
+    ymin_str: "-18",
     xmax: 147,
+    xmax_str: "147",
     ymax: -18,
+    ymax_str: "-18",
     width: 0,
+    width_str: "0",
     height: 0,
+    height_str: "0",
     bottomLeft: { x: 147, y: -18 },
     bottomRight: { x: 147, y: -18 },
     topLeft: { x: 147, y: -18 },
     topRight: { x: 147, y: -18 },
+    leafletBounds: [
+      [-18, 147],
+      [-18, 147]
+    ],
     area: 0,
+    area_str: "0",
     perimeter: 0,
-    bbox: [ 147, -18, 147, -18 ],
+    perimeter_str: "0",
+    bbox: [147, -18, 147, -18],
+    bbox_str: ["147", "-18", "147", "-18"],
     center: { x: 147, y: -18 },
-    str: '147,-18,147,-18',
-    leafletBounds: [
-      [ -18, 147 ],
-      [ -18, 147 ]
-    ]
+    center_str: { x: "147", y: "-18" },
+    str: "147,-18,147,-18"
   };
   eq(new GeoExtent({ x: 147, y: -18 }, { srs: 4326 }).asObj(), EXPECTED_EXTENT_FOR_PT);
-  eq(new GeoExtent([ 147, -18 ], { srs: 4326 }).asObj(), EXPECTED_EXTENT_FOR_PT);
+  eq(new GeoExtent([147, -18], { srs: 4326 }).asObj(), EXPECTED_EXTENT_FOR_PT);
 });
 
 test("reproject from 4326 to 3857", ({ eq }) => {
   const bbox = new GeoExtent(BBOX, { srs: 4326 });
   const extentIn3857 = bbox.reproj(3857);
-  eq(extentIn3857.srs, 'EPSG:3857');
-  eq(extentIn3857.bbox, [
-    -8015003.337115697,
-    -5942074.072431109,
-    2337709.3066587453,
-    12515545.2124676
-  ]);
+  eq(extentIn3857.srs, "EPSG:3857");
+  eq(extentIn3857.bbox, [-8015003.337115697, -5942074.072431109, 2337709.3066587453, 12515545.2124676]);
 });
 
 test("intake Bounds Array", ({ eq }) => {
@@ -103,9 +123,15 @@ test("intake Bounds Array", ({ eq }) => {
 });
 
 test("intake two xy points", ({ eq }) => {
-  const bbox = new GeoExtent([{ x: XMIN, y: YMIN }, { x: XMAX, y: YMAX }], { srs: 4326 });
+  const bbox = new GeoExtent(
+    [
+      { x: XMIN, y: YMIN },
+      { x: XMAX, y: YMAX }
+    ],
+    { srs: 4326 }
+  );
   eq(bbox.asObj(), AS_OBJ_RESULT);
-})
+});
 
 test("overlaps", ({ eq }) => {
   const northernHemisphere = new GeoExtent(NORTHERN_HEMISPHERE);
@@ -117,14 +143,16 @@ test("overlaps", ({ eq }) => {
   eq(northPole.overlaps(southPole), false);
 });
 
-
 test("crop", ({ eq }) => {
   const northernHemisphere = new GeoExtent(NORTHERN_HEMISPHERE, { srs: 4326 });
   const northWestQuarterSphere = new GeoExtent(NORTH_WEST_QUARTER_SPHERE, { srs: 4326 });
   eq(northernHemisphere.crop(WESTERN_HEMISPHERE).bbox, NORTH_WEST_QUARTER_SPHERE);
 
   // northern part
-  const result = new GeoExtent([-180, -85, 180, 85], { srs: 4326 }).reproj(3857).crop(northWestQuarterSphere).reproj(4326);
+  const result = new GeoExtent([-180, -85, 180, 85], { srs: 4326 })
+    .reproj(3857)
+    .crop(northWestQuarterSphere)
+    .reproj(4326);
   eq(result.bbox[0] - -180 < 0.000001, true);
   eq(result.bbox[1] - 0 < 0.000001, true);
   eq(result.bbox[2] - 0 < 0.000001, true);
@@ -139,15 +167,19 @@ test("cropping area in web mercator by globe", ({ eq }) => {
 });
 
 test("cropping global by web mercator globe", ({ eq }) => {
-  const a = new GeoExtent([-20037508.342789244, -20037508.342789255, 20037508.342789244, 20037508.342789244], { srs: 3857 });
+  const a = new GeoExtent([-20037508.342789244, -20037508.342789255, 20037508.342789244, 20037508.342789244], {
+    srs: 3857
+  });
   const b = new GeoExtent([-180, -89.99928, 179.99856, 90], { srs: 4326 });
   const res = a.crop(b);
   eq(res.bbox, [-20037508.342789244, -20037508.342789255, 20037348.0427225, 20037508.342789244]);
 });
 
 test("cropping web mercator tile", ({ eq }) => {
   // web mercator tile x: 964, y: 1704, z: 12
-  const tile = new GeoExtent([-10605790.548624776, 3355891.2898323783, -10596006.609004272, 3365675.2294528796], { srs: 3857 });
+  const tile = new GeoExtent([-10605790.548624776, 3355891.2898323783, -10596006.609004272, 3365675.2294528796], {
+    srs: 3857
+  });
 
   // convert web mercator tile to Latitude/Longitude
   eq(tile.reproj(4326).bbox, [-95.27343750000001, 28.84467368077178, -95.185546875, 28.921631282421277]);
@@ -160,6 +192,3 @@ test("cropping web mercator tile", ({ eq }) => {
 
   eq(partial.bbox, [-10605790.548624776, 3358990.12945602, -10601914.152717294, 3365675.2294528796]);
 });
-
-
-
diff --git a/test/test.precision.js b/test/test.precision.js
@@ -0,0 +1,12 @@
+import test from "flug";
+import { GeoExtent } from "../src/geo-extent.js";
+
+test("precision", ({ eq }) => {
+  const bbox = ["7698736.8577886725053", "160793.853073251455", "10066450.2459496622445", "1322636.683007621705"];
+  const ext = new GeoExtent(bbox);
+  eq(ext.width, 2367713.3881609896);
+  eq(ext.width_str, "2367713.3881609897392");
+  eq(ext.xmin_str, bbox[0]);
+  eq(ext.bbox_str, bbox);
+  eq(ext.str, bbox.join(","));
+});