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Better maxzoom guessing by considering resolution within features

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This commit is contained in:
Eric Fischer
2017-05-30 13:28:25 -07:00
parent 5db7b504e8
commit 331707f88a
4 changed files with 85 additions and 1013 deletions
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main.cpp
+48 -11
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@@ -372,7 +372,7 @@ void *run_sort(void *v) {
return NULL;
}
void do_read_parallel(char *map, long long len, long long initial_offset, const char *reading, struct reader *reader, volatile long long *progress_seq, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, std::vector<std::map<std::string, layermap_entry> > *layermaps, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y, int maxzoom, std::string layername, bool uses_gamma, std::map<std::string, int> const *attribute_types, int separator) {
void do_read_parallel(char *map, long long len, long long initial_offset, const char *reading, struct reader *reader, volatile long long *progress_seq, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, std::vector<std::map<std::string, layermap_entry> > *layermaps, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y, int maxzoom, std::string layername, bool uses_gamma, std::map<std::string, int> const *attribute_types, int separator, double *dist_sum, size_t *dist_count) {
long long segs[CPUS + 1];
segs[0] = 0;
segs[CPUS] = len;
@@ -385,11 +385,15 @@ void do_read_parallel(char *map, long long len, long long initial_offset, const
}
}
double dist_sums[CPUS];
size_t dist_counts[CPUS];
volatile long long layer_seq[CPUS];
for (size_t i = 0; i < CPUS; i++) {
// To preserve feature ordering, unique id for each segment
// begins with that segment's offset into the input
layer_seq[i] = segs[i] + initial_offset;
dist_sums[i] = dist_counts[i] = 0;
}
struct parse_json_args pja[CPUS];
@@ -431,6 +435,8 @@ void do_read_parallel(char *map, long long len, long long initial_offset, const
pja[i].layername = &layername;
pja[i].uses_gamma = uses_gamma;
pja[i].attribute_types = attribute_types;
pja[i].dist_sum = &(dist_sums[i]);
pja[i].dist_count = &(dist_counts[i]);
if (pthread_create(&pthreads[i], NULL, run_parse_json, &pja[i]) != 0) {
perror("pthread_create");
@@ -445,6 +451,9 @@ void do_read_parallel(char *map, long long len, long long initial_offset, const
perror("pthread_join 370");
}
*dist_sum += dist_sums[i];
*dist_count += dist_counts[i];
json_end_map(pja[i].jp);
}
}
@@ -476,6 +485,8 @@ struct read_parallel_arg {
std::string layername;
bool uses_gamma;
std::map<std::string, int> const *attribute_types;
double *dist_sum;
size_t *dist_count;
};
void *run_read_parallel(void *v) {
@@ -497,7 +508,7 @@ void *run_read_parallel(void *v) {
}
madvise(map, rpa->len, MADV_RANDOM); // sequential, but from several pointers at once
do_read_parallel(map, rpa->len, rpa->offset, rpa->reading, rpa->reader, rpa->progress_seq, rpa->exclude, rpa->include, rpa->exclude_all, rpa->fname, rpa->basezoom, rpa->source, rpa->nlayers, rpa->layermaps, rpa->droprate, rpa->initialized, rpa->initial_x, rpa->initial_y, rpa->maxzoom, rpa->layername, rpa->uses_gamma, rpa->attribute_types, rpa->separator);
do_read_parallel(map, rpa->len, rpa->offset, rpa->reading, rpa->reader, rpa->progress_seq, rpa->exclude, rpa->include, rpa->exclude_all, rpa->fname, rpa->basezoom, rpa->source, rpa->nlayers, rpa->layermaps, rpa->droprate, rpa->initialized, rpa->initial_x, rpa->initial_y, rpa->maxzoom, rpa->layername, rpa->uses_gamma, rpa->attribute_types, rpa->separator, rpa->dist_sum, rpa->dist_count);
madvise(map, rpa->len, MADV_DONTNEED);
if (munmap(map, rpa->len) != 0) {
@@ -514,7 +525,7 @@ void *run_read_parallel(void *v) {
return NULL;
}
void start_parsing(int fd, FILE *fp, long long offset, long long len, volatile int *is_parsing, pthread_t *parallel_parser, bool &parser_created, const char *reading, struct reader *reader, volatile long long *progress_seq, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, std::vector<std::map<std::string, layermap_entry> > &layermaps, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y, int maxzoom, std::string layername, bool uses_gamma, std::map<std::string, int> const *attribute_types, int separator) {
void start_parsing(int fd, FILE *fp, long long offset, long long len, volatile int *is_parsing, pthread_t *parallel_parser, bool &parser_created, const char *reading, struct reader *reader, volatile long long *progress_seq, std::set<std::string> *exclude, std::set<std::string> *include, int exclude_all, char *fname, int basezoom, int source, int nlayers, std::vector<std::map<std::string, layermap_entry> > &layermaps, double droprate, int *initialized, unsigned *initial_x, unsigned *initial_y, int maxzoom, std::string layername, bool uses_gamma, std::map<std::string, int> const *attribute_types, int separator, double *dist_sum, size_t *dist_count) {
// This has to kick off an intermediate thread to start the parser threads,
// so the main thread can get back to reading the next input stage while
// the intermediate thread waits for the completion of the parser threads.
@@ -553,6 +564,8 @@ void start_parsing(int fd, FILE *fp, long long offset, long long len, volatile i
rpa->layername = layername;
rpa->uses_gamma = uses_gamma;
rpa->attribute_types = attribute_types;
rpa->dist_sum = dist_sum;
rpa->dist_count = dist_count;
if (pthread_create(parallel_parser, NULL, run_read_parallel, rpa) != 0) {
perror("pthread_create");
@@ -1173,6 +1186,8 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
}
long overall_offset = 0;
double dist_sum = 0;
size_t dist_count = 0;
size_t nsources = sources.size();
for (size_t source = 0; source < nsources; source++) {
@@ -1235,7 +1250,7 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
}
if (map != NULL && map != MAP_FAILED && read_parallel_this) {
do_read_parallel(map, st.st_size - off, overall_offset, reading.c_str(), reader, &progress_seq, exclude, include, exclude_all, fname, basezoom, layer, nlayers, &layermaps, droprate, initialized, initial_x, initial_y, maxzoom, sources[layer].layer, uses_gamma, attribute_types, read_parallel_this);
do_read_parallel(map, st.st_size - off, overall_offset, reading.c_str(), reader, &progress_seq, exclude, include, exclude_all, fname, basezoom, layer, nlayers, &layermaps, droprate, initialized, initial_x, initial_y, maxzoom, sources[layer].layer, uses_gamma, attribute_types, read_parallel_this, &dist_sum, &dist_count);
overall_offset += st.st_size - off;
checkdisk(reader, CPUS);
@@ -1311,7 +1326,7 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
}
fflush(readfp);
start_parsing(readfd, readfp, initial_offset, ahead, &is_parsing, &parallel_parser, parser_created, reading.c_str(), reader, &progress_seq, exclude, include, exclude_all, fname, basezoom, layer, nlayers, layermaps, droprate, initialized, initial_x, initial_y, maxzoom, sources[layer].layer, gamma != 0, attribute_types, read_parallel_this);
start_parsing(readfd, readfp, initial_offset, ahead, &is_parsing, &parallel_parser, parser_created, reading.c_str(), reader, &progress_seq, exclude, include, exclude_all, fname, basezoom, layer, nlayers, layermaps, droprate, initialized, initial_x, initial_y, maxzoom, sources[layer].layer, gamma != 0, attribute_types, read_parallel_this, &dist_sum, &dist_count);
initial_offset += ahead;
overall_offset += ahead;
@@ -1348,7 +1363,7 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
fflush(readfp);
if (ahead > 0) {
start_parsing(readfd, readfp, initial_offset, ahead, &is_parsing, &parallel_parser, parser_created, reading.c_str(), reader, &progress_seq, exclude, include, exclude_all, fname, basezoom, layer, nlayers, layermaps, droprate, initialized, initial_x, initial_y, maxzoom, sources[layer].layer, gamma != 0, attribute_types, read_parallel_this);
start_parsing(readfd, readfp, initial_offset, ahead, &is_parsing, &parallel_parser, parser_created, reading.c_str(), reader, &progress_seq, exclude, include, exclude_all, fname, basezoom, layer, nlayers, layermaps, droprate, initialized, initial_x, initial_y, maxzoom, sources[layer].layer, gamma != 0, attribute_types, read_parallel_this, &dist_sum, &dist_count);
if (parser_created) {
if (pthread_join(parallel_parser, NULL) != 0) {
@@ -1365,7 +1380,7 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
long long layer_seq = overall_offset;
json_pull *jp = json_begin_file(fp);
parse_json(jp, reading.c_str(), &layer_seq, &progress_seq, &reader[0].metapos, &reader[0].geompos, &reader[0].indexpos, exclude, include, exclude_all, reader[0].metafile, reader[0].geomfile, reader[0].indexfile, reader[0].poolfile, reader[0].treefile, fname, basezoom, layer, droprate, reader[0].file_bbox, 0, &initialized[0], &initial_x[0], &initial_y[0], reader, maxzoom, &layermaps[0], sources[layer].layer, uses_gamma, attribute_types);
parse_json(jp, reading.c_str(), &layer_seq, &progress_seq, &reader[0].metapos, &reader[0].geompos, &reader[0].indexpos, exclude, include, exclude_all, reader[0].metafile, reader[0].geomfile, reader[0].indexfile, reader[0].poolfile, reader[0].treefile, fname, basezoom, layer, droprate, reader[0].file_bbox, 0, &initialized[0], &initial_x[0], &initial_y[0], reader, maxzoom, &layermaps[0], sources[layer].layer, uses_gamma, attribute_types, &dist_sum, &dist_count);
json_end(jp);
overall_offset = layer_seq;
checkdisk(reader, CPUS);
@@ -1618,6 +1633,11 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
}
}
if (count == 0 && dist_count == 0) {
fprintf(stderr, "Can't guess maxzoom (-zg) without at least two distinct feature locations\n");
exit(EXIT_FAILURE);
}
if (count > 0) {
// Geometric mean is appropriate because distances between features
// are typically lognormally distributed
@@ -1625,7 +1645,8 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
// Convert approximately from tile units to feet
double dist_ft = sqrt(avg) / 33;
double want = dist_ft / 250;
// Factor of 8 (3 zooms) beyond minimum required to distinguish features
double want = dist_ft / 8;
maxzoom = ceil(log(360 / (.00000274 * want)) / log(2) - full_detail);
if (maxzoom < 0) {
@@ -1638,9 +1659,25 @@ int read_input(std::vector<source> &sources, char *fname, int &maxzoom, int minz
if (!quiet) {
fprintf(stderr, "Choosing a maxzoom of -z%d for features about %d feet apart\n", maxzoom, (int) ceil(dist_ft));
}
} else {
fprintf(stderr, "Can't guess maxzoom (-zg) without at least two distinct feature locations\n");
exit(EXIT_FAILURE);
}
if (dist_count != 0) {
double want2 = exp(dist_sum / dist_count) / 8;
int mz = ceil(log(360 / (.00000274 * want2)) / log(2) - full_detail);
if (mz < 0) {
mz = 0;
}
if (mz > MAX_ZOOM) {
mz = MAX_ZOOM;
}
if (mz > maxzoom || count <= 0) {
if (!quiet) {
fprintf(stderr, "Choosing a maxzoom of -z%d for resolution of about %d feet within features\n", mz, (int) exp(dist_sum / dist_count));
}
maxzoom = mz;
}
}
if (maxzoom < minzoom) {