osrm-backend/third_party/cheap-ruler-cpp-2778eb8/test/cheap_ruler.cpp
Siarhei Fedartsou aadc088084
Fix distance calculation consistency. (#6315)
Consolidate great circle distance calculations to use cheap ruler library.
2022-08-19 22:31:40 +01:00

277 lines
8.7 KiB
C++

#include <mapbox/cheap_ruler.hpp>
#include <gtest/gtest.h>
#include <random>
#include "fixtures/lines.hpp"
#include "fixtures/turf.hpp"
namespace cr = mapbox::cheap_ruler;
class CheapRulerTest : public ::testing::Test {
protected:
cr::CheapRuler ruler = cr::CheapRuler(32.8351);
cr::CheapRuler milesRuler = cr::CheapRuler(32.8351, cr::CheapRuler::Miles);
};
void assertErr(double expected, double actual, double maxError) {
// Add a negligible fraction to make sure we
// don't divide by zero.
double error = std::abs((actual - expected) /
(expected == 0. ? expected + 0.000001 : expected));
if (error > maxError) {
FAIL() << "expected is " << expected << " but got " << actual;
}
}
TEST_F(CheapRulerTest, distance) {
for (unsigned i = 0; i < points.size() - 1; ++i) {
auto expected = turf_distance[i];
auto actual = ruler.distance(points[i], points[i + 1]);
assertErr(expected, actual, .003);
}
}
TEST_F(CheapRulerTest, distanceInMiles) {
auto d = ruler.distance({ 30.5, 32.8351 }, { 30.51, 32.8451 });
auto d2 = milesRuler.distance({ 30.5, 32.8351 }, { 30.51, 32.8451 });
assertErr(d / d2, 1.609344, 1e-12);
}
TEST_F(CheapRulerTest, bearing) {
for (unsigned i = 0; i < points.size() - 1; ++i) {
auto expected = turf_bearing[i];
auto actual = ruler.bearing(points[i], points[i + 1]);
assertErr(expected, actual, .005);
}
}
TEST_F(CheapRulerTest, destination) {
for (unsigned i = 0; i < points.size(); ++i) {
auto bearing = (i % 360) - 180.;
auto expected = turf_destination[i];
auto actual = ruler.destination(points[i], 1.0, bearing);
assertErr(expected.x, actual.x, 1e-6); // longitude
assertErr(expected.y, actual.y, 1e-6); // latitude
}
}
TEST_F(CheapRulerTest, lineDistance) {
{
cr::line_string emptyLine {};
auto expected = 0.0;
auto actual = ruler.lineDistance(emptyLine);
assertErr(expected, actual, 0.0);
}
for (unsigned i = 0; i < lines.size(); ++i) {
auto expected = turf_lineDistance[i];
auto actual = ruler.lineDistance(lines[i]);
assertErr(expected, actual, 0.003);
}
}
TEST_F(CheapRulerTest, area) {
for (unsigned i = 0, j = 0; i < lines.size(); ++i) {
if (lines[i].size() < 3) {
continue;
}
cr::linear_ring ring;
for (auto point : lines[i]) {
ring.push_back(point);
}
ring.push_back(lines[i][0]);
auto expected = turf_area[j++];
auto actual = ruler.area(cr::polygon{ ring });
assertErr(expected, actual, 0.003);
}
}
TEST_F(CheapRulerTest, along) {
{
cr::point emptyPoint {};
cr::line_string emptyLine {};
auto expected = emptyPoint;
auto actual = ruler.along(emptyLine, 0.0);
assertErr(expected.x, actual.x, 0.0);
assertErr(expected.y, actual.y, 0.0);
}
for (unsigned i = 0; i < lines.size(); ++i) {
auto expected = turf_along[i];
auto actual = ruler.along(lines[i], turf_along_dist[i]);
assertErr(expected.x, actual.x, 1e-6); // along longitude
assertErr(expected.y, actual.y, 1e-6); // along latitude
}
}
TEST_F(CheapRulerTest, alongWithDist) {
ASSERT_EQ(ruler.along(lines[0], -5), lines[0][0]);
}
TEST_F(CheapRulerTest, alongWithDistGreaterThanLength) {
ASSERT_EQ(ruler.along(lines[0], 1000), lines[0][lines[0].size() - 1]);
}
TEST_F(CheapRulerTest, pointOnLine) {
// not Turf comparison because pointOnLine is bugged https://github.com/Turfjs/turf/issues/344
cr::line_string line = {{ -77.031669, 38.878605 }, { -77.029609, 38.881946 }};
auto result = ruler.pointOnLine(line, { -77.034076, 38.882017 });
assertErr(std::get<0>(result).x, -77.03052689033436, 1e-6);
assertErr(std::get<0>(result).y, 38.880457324462576, 1e-6);
ASSERT_EQ(std::get<1>(result), 0u); // index
assertErr(std::get<2>(result), 0.5544221677861756, 1e-6); // t
ASSERT_EQ(std::get<2>(ruler.pointOnLine(line, { -80., 38. })), 0.) << "t is not less than 0";
ASSERT_EQ(std::get<2>(ruler.pointOnLine(line, { -75., 38. })), 1.) << "t is not bigger than 1";
}
TEST_F(CheapRulerTest, pointToSegmentDistance) {
cr::point p{ -77.034076, 38.882017 };
cr::point p0{ -77.031669, 38.878605 };
cr::point p1{ -77.029609, 38.881946 };
const auto distance = ruler.pointToSegmentDistance(p, p0, p1);
assertErr(0.37461484020420416, distance, 1e-6);
}
TEST_F(CheapRulerTest, lineSlice) {
for (unsigned i = 0; i < lines.size(); ++i) {
auto line = lines[i];
auto dist = ruler.lineDistance(line);
auto start = ruler.along(line, dist * 0.3);
auto stop = ruler.along(line, dist * 0.7);
auto expected = turf_lineSlice[i];
auto actual = ruler.lineDistance(ruler.lineSlice(start, stop, line));
/// @todo Should update turf_lineSlice and revert maxError back.
assertErr(expected, actual, 1e-4);
}
}
TEST_F(CheapRulerTest, lineSliceAlong) {
{
cr::line_string emptyLine {};
auto expected = ruler.lineDistance(emptyLine);
auto actual = ruler.lineDistance(ruler.lineSliceAlong(0.0, 0.0, emptyLine));
assertErr(expected, actual, 0.0);
}
for (unsigned i = 0; i < lines.size(); ++i) {
if (i == 46) {
// skip due to Turf bug https://github.com/Turfjs/turf/issues/351
continue;
};
auto line = lines[i];
auto dist = ruler.lineDistance(line);
auto expected = turf_lineSlice[i];
auto actual = ruler.lineDistance(ruler.lineSliceAlong(dist * 0.3, dist * 0.7, line));
/// @todo Should update turf_lineSlice and revert maxError back.
assertErr(expected, actual, 1e-4);
}
}
TEST_F(CheapRulerTest, lineSliceReverse) {
auto line = lines[0];
auto dist = ruler.lineDistance(line);
auto start = ruler.along(line, dist * 0.7);
auto stop = ruler.along(line, dist * 0.3);
auto actual = ruler.lineDistance(ruler.lineSlice(start, stop, line));
assertErr(0.018676476689649835, actual, 1e-6);
}
TEST_F(CheapRulerTest, bufferPoint) {
for (unsigned i = 0; i < points.size(); ++i) {
auto expected = turf_bufferPoint[i];
auto actual = milesRuler.bufferPoint(points[i], 0.1);
assertErr(expected.min.x, actual.min.x, 2e-7);
assertErr(expected.min.x, actual.min.x, 2e-7);
assertErr(expected.max.y, actual.max.y, 2e-7);
assertErr(expected.max.y, actual.max.y, 2e-7);
}
}
TEST_F(CheapRulerTest, bufferBBox) {
cr::box bbox({ 30, 38 }, { 40, 39 });
cr::box bbox2 = ruler.bufferBBox(bbox, 1);
assertErr(bbox2.min.x, 29.989319515875376, 1e-6);
assertErr(bbox2.min.y, 37.99098271225711, 1e-6);
assertErr(bbox2.max.x, 40.01068048412462, 1e-6);
assertErr(bbox2.max.y, 39.00901728774289, 1e-6);
}
TEST_F(CheapRulerTest, insideBBox) {
cr::box bbox({ 30, 38 }, { 40, 39 });
ASSERT_TRUE(ruler.insideBBox({ 35, 38.5 }, bbox));
ASSERT_FALSE(ruler.insideBBox({ 45, 45 }, bbox));
}
TEST_F(CheapRulerTest, fromTile) {
auto ruler1 = cr::CheapRuler(50.5);
auto ruler2 = cr::CheapRuler::fromTile(11041, 15);
cr::point p1(30.5, 50.5);
cr::point p2(30.51, 50.51);
assertErr(ruler1.distance(p1, p2), ruler2.distance(p1, p2), 2e-5);
}
TEST_F(CheapRulerTest, longitudeWrap) {
std::random_device rd;
std::mt19937 gen(rd());
std::bernoulli_distribution d(0.5); // true with prob 0.5
auto r = cr::CheapRuler(50.5);
cr::polygon poly(1);
auto& ring = poly[0];
cr::line_string line;
cr::point origin(0, 50.5); // Greenwich
auto rad = 1000.0;
// construct a regular dodecagon
for (int i = -180; i <= 180; i += 30) {
auto p = r.destination(origin, rad, i);
// shift randomly east/west to the international date line
p.x += d(gen) ? 180 : -180;
ring.push_back(p);
line.push_back(p);
}
auto p = r.lineDistance(line);
auto a = r.area(poly);
// cheap_ruler does planar calculations, so the perimeter and area of a
// planar regular dodecagon with circumradius rad are used in these checks.
// For the record, the results for rad = 1000 km are:
// perimeter area
// planar 6211.657082 3000000
// WGS84 6187.959236 2996317.6328
// error 0.38% 0.12%
assertErr(12 * rad / sqrt(2 + sqrt(3.0)), p, 1e-12);
assertErr(3 * rad * rad, a, 1e-12);
for (int j = 1; j < (int)line.size(); ++j) {
auto azi = r.bearing(line[j-1], line[j]);
// offset expect and actual by 1 to make err criterion absolute
assertErr(1, std::remainder(270 - 15 + 30*j - azi, 360) + 1, 1e-12);
}
}
int main(int argc, char **argv) {
::testing::InitGoogleTest(&argc, argv);
return RUN_ALL_TESTS();
}