diegoripley/tippecanoe
1
0
Fork 0
mirror of https://github.com/felt/tippecanoe.git synced 2026-10-02 16:35:40 +02:00
Code Issues Packages Projects Releases Wiki Activity

Weight outlieriness by categoricality

Browse Source
This commit is contained in:
Erica Fischer
2023-02-10 12:21:20 -08:00
parent 82be5627f4
commit 5c681e50d9
3 changed files with 39 additions and 22 deletions
Download Patch File Download Diff File Expand all files Collapse all files
mbtiles.cpp
+15 -9
View File
@@ -908,6 +908,20 @@ std::map<std::string, layermap_entry> merge_layermaps(std::vector<std::map<std::
return out;
}
double categorical_hash(std::string const &val) {
unsigned hash = 0;
for (size_t i = 0; i < val.size(); i++) {
// https://en.wikipedia.org/wiki/Hash_function#Fibonacci_hashing
hash = hash * 2654435769 + val[i];
}
// extra multiply so even single-byte values are distributed
// around the circle rather than clumped together on one side.
hash = hash * 2654435769;
double angle = ((double) hash) / UINT_MAX * 2 * M_PI;
return angle;
}
void add_to_file_keys(std::map<std::string, type_and_string_stats> &file_keys, std::string const &attrib, type_and_string const &val) {
if (val.type == mvt_null) {
return;
@@ -944,15 +958,7 @@ void add_to_file_keys(std::map<std::string, type_and_string_stats> &file_keys, s
}
}
unsigned hash = 0;
for (size_t i = 0; i < val.string.size(); i++) {
// https://en.wikipedia.org/wiki/Hash_function#Fibonacci_hashing
hash = hash * 2654435769 + val.string[i];
}
// extra multiply so even single-byte values are distributed
// around the circle rather than clumped together on one side.
hash = hash * 2654435769;
double angle = ((double) hash) / UINT_MAX * 2 * M_PI;
double angle = categorical_hash(val.string);
double x = cos(angle);
double y = sin(angle);