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shape: check if multiple parts are interior rings or separate

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polygons. Currently only test if first coordinate inside exterior
ring and assume first ring is exterior.

If this approach is not robust enough we can calculate ring orientations
instead. Shape file convention is: CW - exterior, CCW - interior.

very simple
This commit is contained in:
Artem Pavlenko 2012-01-05 16:24:38 +00:00
parent 71c275b86b
commit faaa4f6e3f
1 changed files with 17 additions and 7 deletions
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24
plugins/input/shape/shape_io.cpp
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@ -110,12 +110,12 @@ void shape_io::read_polyline(mapnik::geometry_container & geom)
{
shape_file::record_type record(reclength_ * 2 - 36);
shp_.read_record(record);
int num_parts = record.read_ndr_integer();
int num_points = record.read_ndr_integer();
if (num_parts == 1)
{
geometry_type* line = new geometry_type(mapnik::LineString);
geometry_type* line = new geometry_type(mapnik::LineString);
record.skip(4);
double x = record.read_double();
double y = record.read_double();
@ -139,7 +139,7 @@ void shape_io::read_polyline(mapnik::geometry_container & geom)
int start, end;
for (int k = 0; k < num_parts; ++k)
{
geometry_type* line = new geometry_type(mapnik::LineString);
geometry_type* line = new geometry_type(mapnik::LineString);
start = parts[k];
if (k == num_parts - 1)
{
@ -186,19 +186,21 @@ void shape_io::read_polygon(mapnik::geometry_container & geom)
{
shape_file::record_type record(reclength_ * 2 - 36);
shp_.read_record(record);
int num_parts = record.read_ndr_integer();
int num_points = record.read_ndr_integer();
std::vector<int> parts(num_parts);
for (int i = 0; i < num_parts; ++i)
{
parts[i] = record.read_ndr_integer();
}
geometry_type* poly = new geometry_type(mapnik::Polygon);
for (int k = 0; k < num_parts; k++)
{
geometry_type* poly = new geometry_type(mapnik::Polygon);
int start = parts[k];
int end;
if (k == num_parts - 1)
@ -212,6 +214,13 @@ void shape_io::read_polygon(mapnik::geometry_container & geom)
double x = record.read_double();
double y = record.read_double();
if (k > 0 && !poly->hit_test(x,y,0))
{
geom.push_back(poly);
poly = new geometry_type(mapnik::Polygon);
}
poly->move_to(x, y);
for (int j=start+1;j<end;j++)
@ -220,8 +229,9 @@ void shape_io::read_polygon(mapnik::geometry_container & geom)
y = record.read_double();
poly->line_to(x, y);
}
geom.push_back(poly);
}
geom.push_back(poly);
// z-range
//double z0=record.read_double();
//double z1=record.read_double();