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Add initial ol.geom.simplify

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Tom Payne
2013-12-05 14:13:47 +01:00
parent 94393c0050
commit ec03be94d6
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219
src/ol/geom/simplifygeom.js Normal file
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// Based on simplify-js https://github.com/mourner/simplify-js
// Copyright (c) 2012, Vladimir Agafonkin
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
// 1. Redistributions of source code must retain the above copyright notice,
// this list of conditions and the following disclaimer.
//
// 2. Redistributions in binary form must reproduce the above copyright
// notice, this list of conditions and the following disclaimer in the
// documentation and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
// IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
// ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE
// LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
// CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
// SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
// INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
// CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
goog.provide('ol.geom.simplify');
/**
* @param {Array.<number>} flatCoordinates Flat coordinates.
* @param {number} offset Offset.
* @param {number} end End.
* @param {number} stride Stride.
* @param {number} squaredTolerance Squared tolerance.
* @param {boolean} highQuality Highest quality.
* @param {Array.<number>=} opt_simplifiedFlatCoordinates Simplified flat
* coordinates.
* @return {Array.<number>} Simplified line string.
*/
ol.geom.simplify.lineString = function(flatCoordinates, offset, end, stride,
squaredTolerance, highQuality, opt_simplifiedFlatCoordinates) {
var simplifiedFlatCoordinates = goog.isDef(opt_simplifiedFlatCoordinates) ?
opt_simplifiedFlatCoordinates : [];
if (!highQuality) {
end = ol.geom.simplify.radialDistance(flatCoordinates, offset, end,
stride, squaredTolerance,
simplifiedFlatCoordinates, 0);
flatCoordinates = simplifiedFlatCoordinates;
offset = 0;
stride = 2;
}
simplifiedFlatCoordinates.length = ol.geom.simplify.douglasPeucker(
flatCoordinates, offset, end, stride, squaredTolerance,
simplifiedFlatCoordinates, 0);
return simplifiedFlatCoordinates;
};
/**
* @param {Array.<number>} flatCoordinates Flat coordinates.
* @param {number} offset Offset.
* @param {number} end End.
* @param {number} stride Stride.
* @param {number} squaredTolerance Squared tolerance.
* @param {Array.<number>} simplifiedFlatCoordinates Simplified flat
* coordinates.
* @param {number} simplifiedOffset Simplified offset.
* @return {number} Simplified offset.
*/
ol.geom.simplify.douglasPeucker = function(flatCoordinates, offset, end,
stride, squaredTolerance, simplifiedFlatCoordinates, simplifiedOffset) {
var n = (end - offset) / stride;
if (n < 3) {
for (; offset < end; offset += stride) {
simplifiedFlatCoordinates[simplifiedOffset++] =
flatCoordinates[offset];
simplifiedFlatCoordinates[simplifiedOffset++] =
flatCoordinates[offset + 1];
}
return simplifiedOffset;
}
var MarkerArray = goog.global['Uint8Array'] ? Uint8Array : Array;
var markers = new MarkerArray(n);
markers[0] = 1;
markers[n - 1] = 1;
var stack = [offset, end - stride];
var index = 0;
var i;
while (stack.length > 0) {
var last = stack.pop();
var first = stack.pop();
var maxSquaredDistance = 0;
var x1 = flatCoordinates[first];
var y1 = flatCoordinates[first + 1];
var x2 = flatCoordinates[last];
var y2 = flatCoordinates[last + 1];
for (i = first + stride; i < last; i += stride) {
var x = flatCoordinates[i];
var y = flatCoordinates[i + 1];
var squaredDistance =
ol.geom.simplify.squaredSegmentDistance(x, y, x1, y1, x2, y2);
if (squaredDistance > maxSquaredDistance) {
index = i;
maxSquaredDistance = squaredDistance;
}
}
if (maxSquaredDistance > squaredTolerance) {
markers[(index - offset) / stride] = 1;
if (first + stride < index) {
stack.push(first, index);
}
if (index + stride < last) {
stack.push(index, last);
}
}
}
for (i = 0; i < n; ++i) {
if (markers[i]) {
simplifiedFlatCoordinates[simplifiedOffset++] =
flatCoordinates[offset + i * stride];
simplifiedFlatCoordinates[simplifiedOffset++] =
flatCoordinates[offset + i * stride + 1];
}
}
return simplifiedOffset;
};
/**
* @param {Array.<number>} flatCoordinates Flat coordinates.
* @param {number} offset Offset.
* @param {number} end End.
* @param {number} stride Stride.
* @param {number} squaredTolerance Squared tolerance.
* @param {Array.<number>} simplifiedFlatCoordinates Simplified flat
* coordinates.
* @param {number} simplifiedOffset Simplified offset.
* @return {number} Simplified offset.
*/
ol.geom.simplify.radialDistance = function(flatCoordinates, offset, end,
stride, squaredTolerance, simplifiedFlatCoordinates, simplifiedOffset) {
if (end <= offset + stride) {
// zero or one point, no simplification possible, so copy and return
for (; offset < end; offset += stride) {
simplifiedFlatCoordinates[simplifiedOffset++] = flatCoordinates[offset];
simplifiedFlatCoordinates[simplifiedOffset++] =
flatCoordinates[offset + 1];
}
return simplifiedOffset;
}
var x1 = flatCoordinates[offset];
var y1 = flatCoordinates[offset + 1];
// copy first point
simplifiedFlatCoordinates[simplifiedOffset++] = x1;
simplifiedFlatCoordinates[simplifiedOffset++] = y1;
var x2 = x1;
var y2 = y1;
for (offset += stride; offset < end; offset += stride) {
x2 = flatCoordinates[offset];
y2 = flatCoordinates[offset + 1];
if (ol.geom.simplify.squaredDistance(x1, y1, x2, y2) > squaredTolerance) {
// copy point at offset
simplifiedFlatCoordinates[simplifiedOffset++] = x2;
simplifiedFlatCoordinates[simplifiedOffset++] = y2;
x1 = x2;
y1 = y2;
}
}
if (x2 != x1 || y2 != y1) {
// copy last point
simplifiedFlatCoordinates[simplifiedOffset++] = x2;
simplifiedFlatCoordinates[simplifiedOffset++] = y2;
}
return simplifiedOffset;
};
/**
* Returns the square of the distance between the points (x1, y1) and (x2, y2).
* @param {number} x1 X1.
* @param {number} y1 Y1.
* @param {number} x2 X2.
* @param {number} y2 Y2.
* @return {number} Squared distance.
*/
ol.geom.simplify.squaredDistance = function(x1, y1, x2, y2) {
var dx = x2 - x1;
var dy = y2 - y1;
return dx * dx + dy * dy;
};
/**
* Returns the square of the closest distance between the point (x, y) and the
* line segment (x1, y1) to (x2, y2).
* @param {number} x X.
* @param {number} y Y.
* @param {number} x1 X1.
* @param {number} y1 Y1.
* @param {number} x2 X2.
* @param {number} y2 Y2.
* @return {number} Squared distance.
*/
ol.geom.simplify.squaredSegmentDistance = function(x, y, x1, y1, x2, y2) {
var dx = x2 - x1;
var dy = y2 - y1;
if (dx !== 0 || dy !== 0) {
var t = ((x - x1) * dx + (y - y1) * dy) / (dx * dx + dy * dy);
if (t > 1) {
x1 = x2;
y1 = y2;
} else if (t > 0) {
x1 += dx * t;
y1 += dy * t;
}
}
return ol.geom.simplify.squaredDistance(x, y, x1, y1);
};

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test/spec/ol/geom/simplifygeom.test.js Normal file
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goog.provide('ol.test.geom.simplify');
describe('ol.geom.simplify', function() {
var flatCoordinates = [
224.55, 250.15, 226.91, 244.19, 233.31, 241.45, 234.98, 236.06,
244.21, 232.76, 262.59, 215.31, 267.76, 213.81, 273.57, 201.84,
273.12, 192.16, 277.62, 189.03, 280.36, 181.41, 286.51, 177.74,
292.41, 159.37, 296.91, 155.64, 314.95, 151.37, 319.75, 145.16,
330.33, 137.57, 341.48, 139.96, 369.98, 137.89, 387.39, 142.51,
391.28, 139.39, 409.52, 141.14, 414.82, 139.75, 427.72, 127.30,
439.60, 119.74, 474.93, 107.87, 486.51, 106.75, 489.20, 109.45,
493.79, 108.63, 504.74, 119.66, 512.96, 122.35, 518.63, 120.89,
524.09, 126.88, 529.57, 127.86, 534.21, 140.93, 539.27, 147.24,
567.69, 148.91, 575.25, 157.26, 580.62, 158.15, 601.53, 156.85,
617.74, 159.86, 622.00, 167.04, 629.55, 194.60, 638.90, 195.61,
641.26, 200.81, 651.77, 204.56, 671.55, 222.55, 683.68, 217.45,
695.25, 219.15, 700.64, 217.98, 703.12, 214.36, 712.26, 215.87,
721.49, 212.81, 727.81, 213.36, 729.98, 208.73, 735.32, 208.20,
739.94, 204.77, 769.98, 208.42, 779.60, 216.87, 784.20, 218.16,
800.24, 214.62, 810.53, 219.73, 817.19, 226.82, 820.77, 236.17,
827.23, 236.16, 829.89, 239.89, 851.00, 248.94, 859.88, 255.49,
865.21, 268.53, 857.95, 280.30, 865.48, 291.45, 866.81, 298.66,
864.68, 302.71, 867.79, 306.17, 859.87, 311.37, 860.08, 314.35,
858.29, 314.94, 858.10, 327.60, 854.54, 335.40, 860.92, 343.00,
856.43, 350.15, 851.42, 352.96, 849.84, 359.59, 854.56, 365.53,
849.74, 370.38, 844.09, 371.89, 844.75, 380.44, 841.52, 383.67,
839.57, 390.40, 845.59, 399.05, 848.40, 407.55, 843.71, 411.30,
844.09, 419.88, 839.51, 432.76, 841.33, 441.04, 847.62, 449.22,
847.16, 458.44, 851.38, 462.79, 853.97, 471.15, 866.36, 480.77
];
var simplifiedRadiallyFlatCoordinates = [
224.55, 250.15, 226.91, 244.19, 233.31, 241.45, 234.98, 236.06,
244.21, 232.76, 262.59, 215.31, 267.76, 213.81, 273.57, 201.84,
273.12, 192.16, 277.62, 189.03, 280.36, 181.41, 286.51, 177.74,
292.41, 159.37, 296.91, 155.64, 314.95, 151.37, 319.75, 145.16,
330.33, 137.57, 341.48, 139.96, 369.98, 137.89, 387.39, 142.51,
409.52, 141.14, 414.82, 139.75, 427.72, 127.30, 439.60, 119.74,
474.93, 107.87, 486.51, 106.75, 493.79, 108.63, 504.74, 119.66,
512.96, 122.35, 518.63, 120.89, 524.09, 126.88, 529.57, 127.86,
534.21, 140.93, 539.27, 147.24, 567.69, 148.91, 575.25, 157.26,
580.62, 158.15, 601.53, 156.85, 617.74, 159.86, 622.00, 167.04,
629.55, 194.60, 638.90, 195.61, 641.26, 200.81, 651.77, 204.56,
671.55, 222.55, 683.68, 217.45, 695.25, 219.15, 700.64, 217.98,
712.26, 215.87, 721.49, 212.81, 727.81, 213.36, 729.98, 208.73,
735.32, 208.20, 739.94, 204.77, 769.98, 208.42, 779.60, 216.87,
800.24, 214.62, 810.53, 219.73, 817.19, 226.82, 820.77, 236.17,
827.23, 236.16, 851.00, 248.94, 859.88, 255.49, 865.21, 268.53,
857.95, 280.30, 865.48, 291.45, 866.81, 298.66, 867.79, 306.17,
859.87, 311.37, 858.10, 327.60, 854.54, 335.40, 860.92, 343.00,
856.43, 350.15, 851.42, 352.96, 849.84, 359.59, 854.56, 365.53,
849.74, 370.38, 844.09, 371.89, 844.75, 380.44, 839.57, 390.40,
845.59, 399.05, 848.40, 407.55, 843.71, 411.30, 844.09, 419.88,
839.51, 432.76, 841.33, 441.04, 847.62, 449.22, 847.16, 458.44,
851.38, 462.79, 853.97, 471.15, 866.36, 480.77
];
var simplifiedFlatCoordinates = [
224.55, 250.15, 267.76, 213.81, 296.91, 155.64, 330.33, 137.57,
409.52, 141.14, 439.60, 119.74, 486.51, 106.75, 529.57, 127.86,
539.27, 147.24, 617.74, 159.86, 629.55, 194.60, 671.55, 222.55,
727.81, 213.36, 739.94, 204.77, 769.98, 208.42, 779.60, 216.87,
800.24, 214.62, 820.77, 236.17, 859.88, 255.49, 865.21, 268.53,
857.95, 280.30, 867.79, 306.17, 859.87, 311.37, 854.54, 335.40,
860.92, 343.00, 849.84, 359.59, 854.56, 365.53, 844.09, 371.89,
839.57, 390.40, 848.40, 407.55, 839.51, 432.76, 853.97, 471.15,
866.36, 480.77
];
var simplifiedHighQualityFlatCoordinates = [
224.55, 250.15, 267.76, 213.81, 296.91, 155.64, 330.33, 137.57,
409.52, 141.14, 439.60, 119.74, 486.51, 106.75, 529.57, 127.86,
539.27, 147.24, 617.74, 159.86, 629.55, 194.60, 671.55, 222.55,
727.81, 213.36, 739.94, 204.77, 769.98, 208.42, 784.20, 218.16,
800.24, 214.62, 820.77, 236.17, 859.88, 255.49, 865.21, 268.53,
857.95, 280.30, 867.79, 306.17, 858.29, 314.94, 854.54, 335.40,
860.92, 343.00, 849.84, 359.59, 854.56, 365.53, 844.09, 371.89,
839.57, 390.40, 848.40, 407.55, 839.51, 432.76, 853.97, 471.15,
866.36, 480.77
];
describe('ol.geom.simplify.lineString', function() {
it('works with empty line strings', function() {
expect(ol.geom.simplify.lineString([], 0, 0, 2, 1, true)).to.
eql([]);
expect(ol.geom.simplify.lineString([], 0, 0, 2, 1, false)).to.
eql([]);
});
it('works with a line string with a single point', function() {
expect(ol.geom.simplify.lineString([1, 2], 0, 2, 2, 1, true)).to.
eql([1, 2]);
expect(ol.geom.simplify.lineString([1, 2], 0, 2, 2, 1, false)).to.
eql([1, 2]);
});
it('returns the expected result with low quality', function() {
var result = ol.geom.simplify.lineString(
flatCoordinates, 0, flatCoordinates.length, 2, 25, false);
expect(result.length).to.be(simplifiedFlatCoordinates.length);
expect(result).to.eql(simplifiedFlatCoordinates);
});
it('returns the expected result with high quality', function() {
var result = ol.geom.simplify.lineString(
flatCoordinates, 0, flatCoordinates.length, 2, 25, true);
expect(result.length).to.be(simplifiedHighQualityFlatCoordinates.length);
expect(result).to.eql(simplifiedHighQualityFlatCoordinates);
});
});
describe('ol.geom.simplify.radialDistance', function() {
var dest;
beforeEach(function() {
dest = [];
});
it('works with empty line strings', function() {
expect(ol.geom.simplify.radialDistance(
[], 0, 0, 2, 1, dest, 0)).to.be(0);
expect(dest).to.eql([]);
});
it('works with a line string with a single point', function() {
expect(ol.geom.simplify.radialDistance(
[1, 2], 0, 2, 2, 1, dest, 0)).to.be(2);
expect(dest).to.eql([1, 2]);
});
it('works with a line string with two points', function() {
expect(ol.geom.simplify.radialDistance(
[1, 2, 3, 4], 0, 4, 2, 1, dest, 0)).to.be(4);
expect(dest).to.eql([1, 2, 3, 4]);
});
it('works when the points are widely spaced', function() {
expect(ol.geom.simplify.radialDistance(
[0, 0, 1, 0, 2, 0, 3, 0], 0, 8, 2, 0.5, dest, 0)).to.be(8);
expect(dest).to.eql([0, 0, 1, 0, 2, 0, 3, 0]);
});
it('works when the spacing matches the tolerance', function() {
expect(ol.geom.simplify.radialDistance(
[0, 0, 1, 0, 2, 0, 3, 0], 0, 8, 2, 1, dest, 0)).to.be(6);
expect(dest).to.eql([0, 0, 2, 0, 3, 0]);
});
it('works when the points are closely spaced', function() {
expect(ol.geom.simplify.radialDistance(
[0, 0, 1, 0, 2, 0, 3, 0], 0, 8, 2, 1.5, dest, 0)).to.be(6);
expect(dest).to.eql([0, 0, 2, 0, 3, 0]);
});
it('works when the line oscillates with widely spaced points', function() {
expect(ol.geom.simplify.radialDistance(
[0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1], 0, 12, 2, 1, dest, 0)).
to.be(12);
expect(dest).to.eql([0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1]);
});
it('works when the line oscillates with closely spaced points', function() {
expect(ol.geom.simplify.radialDistance(
[0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1], 0, 12, 2, 2, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 1, 1]);
});
it('works when the line oscillates within the tolerance', function() {
expect(ol.geom.simplify.radialDistance(
[0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0], 0, 14, 2, 2, dest, 0)).
to.be(2);
expect(dest).to.eql([0, 0]);
});
it('works with real data', function() {
expect(ol.geom.simplify.radialDistance(
flatCoordinates, 0, flatCoordinates.length, 2, 25, dest, 0)).
to.be(simplifiedRadiallyFlatCoordinates.length);
expect(dest).to.eql(simplifiedRadiallyFlatCoordinates);
});
});
describe('ol.geom.simplify.douglasPeucker', function() {
var dest;
beforeEach(function() {
dest = [];
});
it('works with empty line strings', function() {
expect(ol.geom.simplify.douglasPeucker(
[], 0, 0, 2, 1, dest, 0)).to.be(0);
expect(dest).to.eql([]);
});
it('works with a line string with a single point', function() {
expect(ol.geom.simplify.douglasPeucker(
[1, 2], 0, 2, 2, 1, dest, 0)).to.be(2);
expect(dest).to.eql([1, 2]);
});
it('works with a line string with two points', function() {
expect(ol.geom.simplify.douglasPeucker(
[1, 2, 3, 4], 0, 4, 2, 1, dest, 0)).to.be(4);
expect(dest).to.eql([1, 2, 3, 4]);
});
it('works when the points are widely spaced', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 0, 2, 0, 3, 0], 0, 8, 2, 0.5, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 3, 0]);
});
it('works when the spacing matches the tolerance', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 0, 2, 0, 3, 0], 0, 8, 2, 1, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 3, 0]);
});
it('works when the points are closely spaced', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 0, 2, 0, 3, 0], 0, 8, 2, 1.5, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 3, 0]);
});
it('does not elimnate points outside the tolerance', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 2, 0], 0, 6, 2, 0.5, dest, 0)).to.be(6);
expect(dest).to.eql([0, 0, 1, 1, 2, 0]);
});
it('does eliminate points within the tolerance', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 2, 0], 0, 6, 2, 2, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 2, 0]);
});
it('does not eliminate multiple points outside the tolerance', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 1, -1, 2, 0], 0, 8, 2, 0.5, dest, 0)).to.be(8);
expect(dest).to.eql([0, 0, 1, 1, 1, -1, 2, 0]);
});
it('does eliminate multiple points within the tolerance', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 1, -1, 2, 0], 0, 8, 2, 2, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 2, 0]);
});
it('works when the line oscillates with widely spaced points', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1], 0, 12, 2, 1, dest, 0)).to.be(4);
expect(dest).to.eql([0, 0, 1, 1]);
});
it('works when the line oscillates with closely spaced points', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1], 0, 12, 2, 2, dest, 0)).
to.be(4);
expect(dest).to.eql([0, 0, 1, 1]);
});
it('works when the line oscillates within the tolerance', function() {
expect(ol.geom.simplify.douglasPeucker(
[0, 0, 1, 1, 0, 0, 1, 1, 0, 0, 1, 1, 0, 0], 0, 14, 2, 2, dest, 0)).
to.be(4);
expect(dest).to.eql([0, 0, 0, 0]);
});
it('works on small triangles', function() {
expect(ol.geom.simplify.douglasPeucker(
[3, 0, 4, 1, 5, 2, 5, 0], 0, 8, 2, 1, dest, 0)).to.be(6);
expect(dest).to.eql([3, 0, 5, 2, 5, 0]);
});
it('is the same as high quality simplification', function() {
expect(ol.geom.simplify.douglasPeucker(
flatCoordinates, 0, flatCoordinates.length, 2, 25, dest, 0)).
to.be(simplifiedHighQualityFlatCoordinates.length);
expect(dest).to.eql(simplifiedHighQualityFlatCoordinates);
});
});
});
goog.require('ol.geom.simplify');