added shrink and shrink_density

docs/functions/reproj.md

@@ -43,4 +43,13 @@ extent.reproj(4326, {
   // which is passed to https://github.com/danieljdufour/bbox-fns#densepolygon
   density: [100, 125]
 });
+```
+
+## shrinking
+Sometimes reprojecting a bounding box extends pass the valid bounds of the new projection, leading to NaN values.  You can effectively shrink the bounding box, so it fits into the new projection's bounds, by pasing `shrink: true` and a `shrink_density` number.  This works by essentially densifying the edges and disregarding points on the edges reprojected as NaN values.
+```js
+const northPole = new GeoExtent([-180, 85, 180, 90], { srs: 4326 });
+
+northPole.reproj(3857, { shrink: true, shrink_density: 100 }).bbox;
+[-20037508.342789244, 19971868.880408563, 20037508.342789244, 49411788.9015311]
 ```

package.json

@@ -54,22 +54,22 @@
   "homepage": "https://github.com/DanielJDufour/geo-extent#readme",
   "devDependencies": {
     "@babel/cli": "^7.23.4",
-    "@babel/core": "^7.23.6",
+    "@babel/core": "^7.23.7",
     "@babel/helper-compilation-targets": "^7.23.6",
     "@babel/helper-validator-option": "^7.23.5",
     "@babel/plugin-transform-modules-commonjs": "^7.23.3",
-    "esbuild": "^0.19.10",
-    "flug": "^2.7.1",
+    "esbuild": "^0.19.11",
+    "flug": "^2.7.2",
     "global-jsdom": "^9.2.0",
-    "jsdom": "^23.0.1",
+    "jsdom": "^23.2.0",
     "leaflet": "^1.9.4"
   },
   "dependencies": {
-    "bbox-fns": "^0.19.0",
+    "bbox-fns": "^0.20.2",
     "geography-markup-language": "^0.2.0",
     "get-epsg-code": "1.2.0",
-    "preciso": "^0.12.0",
-    "reproject-bbox": "^0.12.0",
+    "preciso": "^0.12.2",
+    "reproject-bbox": "^0.13.1",
     "reproject-geojson": "^0.5.0"
   }
 }

src/geo-extent.js

@@ -458,10 +458,20 @@ export class GeoExtent {
 
   reproj(
     to,
-    { allow_infinity = false, debug_level = 0, density = "high", quiet = false } = {
+    {
+      allow_infinity = false,
+      debug_level = 0,
+      density = "high",
+      shrink = false,
+      shrink_density = 100,
+      split = true,
+      quiet = false
+    } = {
       allow_infinity: false,
       debug_level: 0,
       density: "high",
+      shrink: false,
+      split: true,
       quiet: false
     }
   ) {
@@ -497,19 +507,22 @@ export class GeoExtent {
 
     let reprojected;
     try {
-      reprojected = reprojectBoundingBox({
+      const options = {
         bbox: this.bbox,
         density,
         from: this.srs,
+        split,
         to
-      });
+      };
+      reprojected = reprojectBoundingBox(options);
     } catch (error) {
       if (debug_level) console.error(error);
     }
 
     if (reprojected?.every(isFinite)) {
       return new GeoExtent(reprojected, { srs: to });
     }
+
     // as a fallback, try reprojecting to EPSG:4326 then to the desired srs
     if (to !== 4326) {
       let bbox_4326;
@@ -518,6 +531,7 @@ export class GeoExtent {
           bbox: this.bbox,
           density,
           from: this.srs,
+          split,
           to: 4326
         });
       } catch (error) {
@@ -530,6 +544,7 @@ export class GeoExtent {
             bbox: bbox_4326,
             density,
             from: 4326,
+            split,
             to
           });
         } catch (err) {
@@ -538,7 +553,36 @@ export class GeoExtent {
       }
     }
 
-    if (allow_infinity || reprojected?.every(isFinite)) {
+    if (reprojected && (allow_infinity || reprojected?.every(isFinite))) {
+      return new GeoExtent(reprojected, { srs: to });
+    }
+
+    // if really haven't gotten a solution yet,
+    // such as when reprojecting globe into Web Mercator
+    // reproject with shrinking and highest density
+    if (shrink) {
+      try {
+        if (shrink_density === "lowest") shrink_density = 1;
+        else if (shrink_density === "low") shrink_density = 2;
+        else if (shrink_density === "medium") shrink_density = 10;
+        else if (shrink_density === "high") shrink_density = 100;
+        else if (shrink_density === "higher") shrink_density = 1000;
+        else if (shrink_density === "highest") shrink_density = 10000;
+
+        reprojected = reprojectBoundingBox({
+          bbox: this.bbox,
+          density: shrink_density,
+          from: this.srs,
+          nan_strategy: "skip",
+          split: true,
+          to
+        });
+      } catch (err) {
+        if (debug_level) console.error(`failed to reproject from bbox ${this.bbox} with shrinking to ${to}`);
+      }
+    }
+
+    if (reprojected && (allow_infinity || reprojected?.every(isFinite))) {
       return new GeoExtent(reprojected, { srs: to });
     } else if (quiet) {
       return;

test/test.reproj.js

@@ -13,23 +13,23 @@ test("reproj error", ({ eq }) => {
 
 test("north pole", ({ eq }) => {
   const northPole = new GeoExtent([-180, 85, 180, 90], { srs: 4326 });
-  let msg;
-  try {
-    northPole.reproj(3857);
-  } catch (error) {
-    msg = error.message;
-  }
-  eq(msg.includes("failed to reproject"), true);
-
-  eq(northPole.reproj(3857, { quiet: true }), undefined);
+  eq(
+    northPole.reproj(3857, { shrink: true }).bbox,
+    [-20037508.342789244, 19971868.880408563, 20037508.342789244, 49411788.9015311]
+  );
+  eq(
+    northPole.reproj(3857, { shrink: true, shrink_density: 100 }).bbox,
+    [-20037508.342789244, 19971868.880408563, 20037508.342789244, 49411788.9015311]
+  );
+  eq(northPole.reproj(3857, { split: false, quiet: true })?.js, undefined);
 });
 
 test("reproject extent that crosses 180th meridian", ({ eq }) => {
   // technically this layer is self-overlapping
   const lyr = new GeoExtent([-180.00092731781535, 15.563268747733936, 179.99907268220255, 74.71076874773686], {
     srs: 4326
   });
-  const result = lyr.reproj(3857);
+  const result = lyr.reproj(3857, { debug_level: 0 });
   eq(result.bbox, [-20037508.342789244, 1754201.542789432, 20037508.342789244, 12808999.953599941]);
 });
 
@@ -73,38 +73,43 @@ test("reproject extent that bends out", ({ eq }) => {
   const srs = 6623;
   const extent = new GeoExtent(bbox, { srs });
   eq(
-    extent.reproj(4326, { density: "lowest" }).bbox,
+    extent.reproj(4326, { density: "lowest", split: false }).bbox,
     [-104.15783650020958, 22.33428366410961, -51.769705847928805, 56.48158793780131]
   );
   eq(
-    extent.reproj(4326, { density: "low" }).bbox,
+    extent.reproj(4326, { density: "low", split: false }).bbox,
     [-104.15783650020958, 22.33428366410961, -51.769705847928805, 57.099578714450445]
   );
   eq(
-    extent.reproj(4326, { density: "medium" }).bbox,
+    extent.reproj(4326, { density: "medium", split: false }).bbox,
     [-104.15783650020958, 22.33428366410961, -51.769705847928805, 57.52407399197629]
   );
   eq(
-    extent.reproj(4326, { density: "high" }).bbox,
+    extent.reproj(4326, { density: "high", split: false }).bbox,
     [-104.15783650020958, 22.33428366410961, -51.769705847928805, 57.53583071204875]
   );
   eq(
-    extent.reproj(4326, { density: "higher" }).bbox,
+    extent.reproj(4326, { density: "higher", split: false }).bbox,
     [-104.15783650020958, 22.33428366410961, -51.769705847928805, 57.53588499736936]
   );
   eq(
-    extent.reproj(4326, { density: "highest" }).bbox,
+    extent.reproj(4326, { density: "highest", split: false }).bbox,
     [-104.15783650020958, 22.33428366410961, -51.769705847928805, 57.535885041786784]
   );
+  eq(
+    extent.reproj(4326, { density: "highest", split: true }).bbox,
+    [-104.15783650020958, 22.33428366410961, -51.769705847928805, 57.53588504321043]
+  );
 });
 
 test("reproj to inf", ({ eq }) => {
   const bbox = [-10018754.171394622, -7.081154551613622e-10, 0, 10018754.171394624];
   const srs = "EPSG:3857";
 
   let msg;
+  let result;
   try {
-    new GeoExtent(bbox, { srs }).reproj(26916, { debug: false, density: 100 });
+    result = new GeoExtent(bbox, { srs }).reproj(26916, { debug: false, density: 100 });
   } catch (error) {
     msg = error.message;
   }
@@ -120,3 +125,23 @@ test("reproj to inf", ({ eq }) => {
     Infinity
   ]);
 });
+
+test("south pole", ({ eq }) => {
+  const ext = new GeoExtent([-3950000, -3943750, 3950000, 4350000], { srs: "EPSG:3031" });
+  eq(
+    ext.reproj(4326, { debug_level: 10, density: "highest", split: true }).bbox,
+    [-179.9942619157211, -90, 180, -39.36335491661697]
+  );
+});
+
+test("split", ({ eq }) => {
+  const ext = new GeoExtent([-180, -85.0511287798066, 179.99856, 85.0511287798066], { srs: "EPSG:4326" });
+  const reprojected = ext.reproj(3857).bbox;
+  eq(reprojected, [-20037508.342789244, -20037508.342789255, 20037348.0427225, 20037508.342789244]);
+});
+
+test("split again", ({ eq }) => {
+  const ext = new GeoExtent([-180, -89.99928, 179.99856, 90], { srs: "EPSG:4326" });
+  const reprojected = ext.reproj("EPSG:3857", { debug_level: 0, shrink: true });
+  eq(reprojected.bbox, [-20037508.342789244, -76394987.3448674, 20037348.0427225, 30976473.682611432]);
+});