[mapcode] 09/32: Added -g/--grid and -r/--random options
Stefan Fritsch
sf at moszumanska.debian.org
Wed Nov 2 23:27:15 UTC 2016
This is an automated email from the git hooks/post-receive script.
sf pushed a commit to annotated tag v1.33
in repository mapcode.
commit 78bed3db3291a0dc121359f6f0956c0e71753064
Author: Rijn Buve <rijn at buve.nl>
Date: Thu Aug 21 10:45:04 2014 +0200
Added -g/--grid and -r/--random options
---
mapcode.c | 106 +++++++++++++++++++++++++++++++++++++++++++-------------------
1 file changed, 73 insertions(+), 33 deletions(-)
diff --git a/mapcode.c b/mapcode.c
index fa54020..3e3d72e 100644
--- a/mapcode.c
+++ b/mapcode.c
@@ -21,19 +21,48 @@ static void usage(const char* appName) {
printf(" Encode a lat/lon to a Mapcode. If the territory code is specified, the\n");
printf(" encoding will only succeeed if the lat/lon is located in the territory.\n");
printf("\n");
- printf(" %s [-g | --generate] <nrPoints> [<seed>]\n", appName);
+ printf(" %s [-g | --grid] <nrPoints> [<seed>]\n", appName);
+ printf(" %s [-r | --random] <nrPoints> [<seed>]\n", appName);
printf("\n");
- printf(" Create a test set of a number of uniformly distributed lat/lon pairs,\n");
- printf(" 3D x/y/z points and their Mapcodes). The output format is:\n");
- printf(" <nr> <lat> <lon> <x> <y> <z>\n");
- printf(" <territory> <mapcode> (repeated 'nr' rtimes)\n");
- printf(" <1 empty line>\n");
+ printf(" Create a test set of a number of a grid or random uniformly distributed\n");
+ printf(" lat/lon pairs, (x, y, z) points and the Mapcode aliases.\n");
printf("\n");
- printf(" The points will be uniformly distributed over the 3D surface of the Earth\n");
- printf(" rather than using uniformly distributed lat/lon values.\n");
+ printf(" The output format is:\n");
+ printf(" <number-of-aliases> <lat-deg> <lon-deg> <x> <y> <z>\n");
+ printf(" <territory> <mapcode> (repeated 'number-of-aliases' times)\n");
+ printf(" (empty lines and next record)\n");
printf(" Ranges:\n");
- printf(" nr > 1 lat = -90..90 lon = -180..180 x,y,z = -1..1\n");
+ printf(" number-of-aliases : >= 1\n");
+ printf(" lat-deg, lon-deg : [-90..90], [-180..180]\n");
+ printf(" x, y, z : [-1..1]\n");
printf("\n");
+ printf(" The lat/lon pairs will be distributed over the 3D surface of the Earth\n");
+ printf(" and the (x, y, z) coordinates are placed on a sphere with radius 1.\n");
+}
+
+/**
+ * Given a single number between 0..1, generate a latitude, longitude (in degrees) and a 3D
+ * (x, y, z) point on a sphere with a radius of 1.
+ */
+static void unitToLatLonDegXYZ(
+ const double unit, double* latDeg, double* lonDeg, double* x, double* y, double* z) {
+
+ // Calculate uniformly distributed 3D point on sphere (radius = 1.0):
+ // http://mathproofs.blogspot.co.il/2005/04/uniform-random-distribution-on-sphere.html
+ const double theta0 = (2.0 * PI) * unit;
+ const double theta1 = acos(1.0 - (2.0 * unit));
+ *x = sin(theta0) * sin(theta1);
+ *y = cos(theta0) * sin(theta1);
+ *z = cos(theta1);
+
+ // Convert Carthesian 3D point into lat/lon (radius = 1.0):
+ // http://stackoverflow.com/questions/1185408/converting-from-longitude-latitude-to-cartesian-coordinates
+ const double latRad = asin(*z);
+ const double lonRad = atan2(*y, *x);
+
+ // Convert radians to degrees.
+ *latDeg = latRad * (180.0 / PI);
+ *lonDeg = lonRad * (180.0 / PI);
}
int main(const int argc, const char** argv)
@@ -53,6 +82,7 @@ int main(const int argc, const char** argv)
// Decode: [-d | --decode] <default-territory> <mapcode> [<mapcode> ...]
// ------------------------------------------------------------------
if (argc < 4) {
+ printf("error: incorrect number of arguments\n\n");
usage(appName);
return -1;
}
@@ -76,6 +106,7 @@ int main(const int argc, const char** argv)
// Encode: [-e | --encode] <lat:-90..90> <lon:-180..180> [territory]>
// ------------------------------------------------------------------
if ((argc != 4) && (argc != 5)) {
+ printf("error: incorrect number of arguments\n\n");
usage(appName);
return -1;
}
@@ -96,45 +127,53 @@ int main(const int argc, const char** argv)
printf("%s %s\n", results[(i * 2) + 1], results[(i * 2)]);
}
}
- else if ((strcmp(cmd, "-g") == 0) || (strcmp(cmd, "--generate") == 0)) {
+ else if ((strcmp(cmd, "-g") == 0) || (strcmp(cmd, "--grid") == 0) ||
+ (strcmp(cmd, "-r") == 0) || (strcmp(cmd, "--random") == 0)) {
// ------------------------------------------------------------------
- // Generate uniform test set: [-g | --generate] <nrPoints> [<seed>]
+ // Generate grid test set: [-g | --grid] <nrPoints>
+ // Generate uniform test set: [-r | --random] <nrPoints> [<seed>]
// ------------------------------------------------------------------
- if ((argc != 3) && (argc != 4)) {
+ if ((argc < 3) || (argc > 4)) {
+ printf("error: incorrect number of arguments\n\n");
usage(appName);
return -1;
}
const int nrPoints = atoi(argv[2]);
-
- if (argc == 4) {
- const int seed = atoi(argv[3]);
- srand(seed);
+ int random = (strcmp(cmd, "-r") == 0) || (strcmp(cmd, "--random") == 0);
+ if (random) {
+ if (argc == 4) {
+ const int seed = atoi(argv[3]);
+ srand(seed);
+ }
+ else {
+ srand(time(0));
+ }
}
else {
- srand(time(0));
+ if (argc > 3) {
+ printf("error: cannot specify seed for -g/--grid\n\n");
+ usage(appName);
+ return -1;
+ }
}
+
const char* results[32];
int context = 0;
- for (int i = 0; i < nrPoints; ++i) {
- // Calculate uniformly distributed 3D point on sphere (radius = 1.0):
- // http://mathproofs.blogspot.co.il/2005/04/uniform-random-distribution-on-sphere.html
- const double unitRand = ((double) rand()) / RAND_MAX;
- const double theta0 = (2.0 * PI) * unitRand;
- const double theta1 = acos(1.0 - (2.0 * unitRand));
- const double x = sin(theta0) * sin(theta1);
- const double y = cos(theta0) * sin(theta1);
- const double z = cos(theta1);
+ double walker = 0.0;
+ const double increment = 1.0 / nrPoints;
+
+ for (int i = 0; i < nrPoints; ++i) {
- // Convert Carthesian 3D point into lat/lon (radius = 1.0):
- // http://stackoverflow.com/questions/1185408/converting-from-longitude-latitude-to-cartesian-coordinates
- const double latRad = asin(z);
- const double lonRad = atan2(y, x);
+ double lat;
+ double lon;
+ double x;
+ double y;
+ double z;
+ double unit = (random ? (((double) rand()) / RAND_MAX) : walker);
- // Convert radians to degrees.
- const double lat = latRad * (180.0 / PI);
- const double lon = lonRad * (180.0 / PI);
+ unitToLatLonDegXYZ(unit, &lat, &lon, &x, &y, &z);
const int nrResults = coord2mc(results, lat, lon, context);
if (nrResults <= 0) {
@@ -146,6 +185,7 @@ int main(const int argc, const char** argv)
printf("%s %s\n", results[(i * 2) + 1], results[(i * 2)]);
}
printf("\n");
+ walker += increment;
}
}
else {
--
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