From 33ef64c9120ad7ba3ce26951356c2e1bbbc360c9 Mon Sep 17 00:00:00 2001
From: Ben Kuster <bkuster@virtualcitysystems.de>
Date: Thu, 12 Jul 2018 12:52:05 +0200
Subject: [PATCH 1/2] copy ZM values to polygon in makeRegular

---
 src/ol/geom/Polygon.js            | 3 +++
 test/spec/ol/geom/polygon.test.js | 8 ++++++++
 2 files changed, 11 insertions(+)

diff --git a/src/ol/geom/Polygon.js b/src/ol/geom/Polygon.js
index 94af9ba32a..280405ac91 100644
--- a/src/ol/geom/Polygon.js
+++ b/src/ol/geom/Polygon.js
@@ -434,6 +434,9 @@ export function makeRegular(polygon, center, radius, opt_angle) {
     const angle = startAngle + (modulo(i, sides) * 2 * Math.PI / sides);
     flatCoordinates[offset] = center[0] + (radius * Math.cos(angle));
     flatCoordinates[offset + 1] = center[1] + (radius * Math.sin(angle));
+    for (let j = 2; j < stride; j++) {
+      flatCoordinates[offset + j] = center[j];
+    }
   }
   polygon.changed();
 }
diff --git a/test/spec/ol/geom/polygon.test.js b/test/spec/ol/geom/polygon.test.js
index 1964c0e4e2..2fee739827 100644
--- a/test/spec/ol/geom/polygon.test.js
+++ b/test/spec/ol/geom/polygon.test.js
@@ -605,6 +605,14 @@ describe('ol/geom/Polygon', function() {
       expect(coordinates[0][0]).to.roughlyEqual(0, 1e-9);
       expect(coordinates[0][1]).to.roughlyEqual(1, 1e-9);
     });
+
+    it('creates a regular polygon, maintaining ZM values', () => {
+      const circle = new Circle([0, 0, 1, 1], 1, 'XYZM');
+      const polygon = fromCircle(circle);
+      const coordinates = polygon.getLinearRing(0).getCoordinates();
+      expect(coordinates[0][2]).to.eql(1);
+      expect(coordinates[0][3]).to.eql(1);
+    });
   });
 
 });

From 88fbd6e35d7234ef7b678f9cec041b2edc140665 Mon Sep 17 00:00:00 2001
From: Ben Kuster <bkuster@virtualcitysystems.de>
Date: Thu, 12 Jul 2018 17:25:31 +0200
Subject: [PATCH 2/2] moved copying of ZM values to Polygon.fromCircle

---
 src/ol/geom/Polygon.js | 12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

diff --git a/src/ol/geom/Polygon.js b/src/ol/geom/Polygon.js
index 280405ac91..eeca8df751 100644
--- a/src/ol/geom/Polygon.js
+++ b/src/ol/geom/Polygon.js
@@ -404,14 +404,19 @@ export function fromCircle(circle, opt_sides, opt_angle) {
   const sides = opt_sides ? opt_sides : 32;
   const stride = circle.getStride();
   const layout = circle.getLayout();
+  const center = circle.getCenter();
   const arrayLength = stride * (sides + 1);
   const flatCoordinates = new Array(arrayLength);
-  for (let i = 0; i < arrayLength; i++) {
+  for (let i = 0; i < arrayLength; i += stride) {
     flatCoordinates[i] = 0;
+    flatCoordinates[i + 1] = 0;
+    for (let j = 2; j < stride; j++) {
+      flatCoordinates[i + j] = center[j];
+    }
   }
   const ends = [flatCoordinates.length];
   const polygon = new Polygon(flatCoordinates, layout, ends);
-  makeRegular(polygon, circle.getCenter(), circle.getRadius(), opt_angle);
+  makeRegular(polygon, center, circle.getRadius(), opt_angle);
   return polygon;
 }
 
@@ -434,9 +439,6 @@ export function makeRegular(polygon, center, radius, opt_angle) {
     const angle = startAngle + (modulo(i, sides) * 2 * Math.PI / sides);
     flatCoordinates[offset] = center[0] + (radius * Math.cos(angle));
     flatCoordinates[offset + 1] = center[1] + (radius * Math.sin(angle));
-    for (let j = 2; j < stride; j++) {
-      flatCoordinates[offset + j] = center[j];
-    }
   }
   polygon.changed();
 }