finish exposing mapnik.Feature.from_geojson

CHANGELOG.md

@@ -8,6 +8,8 @@ For a complete change history, see the git log.
 
 ## Future
 
+- Added the ability to create a mapnik Feature from a geojson feature with `mapnik.Feature.from_geojson` in python.
+
 - Added to python bindings: `has_tiff`, `has_png`, `has_webp`, `has_proj4`, `has_svg_renderer`, and `has_grid_renderer`
 
 - Made it possible to disable compilation of `grid_renderer` with `./configure GRID_RENDERER=False` (#1962)

bindings/python/mapnik_feature.cpp

@@ -30,12 +30,15 @@
 #include <boost/python.hpp>
 #include <boost/noncopyable.hpp>
 
+
 // mapnik
 #include <mapnik/feature.hpp>
+#include <mapnik/feature_factory.hpp>
 #include <mapnik/feature_kv_iterator.hpp>
 #include <mapnik/datasource.hpp>
 #include <mapnik/wkb.hpp>
 #include <mapnik/wkt/wkt_factory.hpp>
+#include <mapnik/json/feature_parser.hpp>
 #include <mapnik/json/geojson_generator.hpp>
 
 // stl
@@ -49,7 +52,7 @@ using mapnik::context_type;
 using mapnik::context_ptr;
 using mapnik::feature_kv_iterator;
 
-mapnik::geometry_type const& (mapnik::feature_impl::*get_geometry_by_const_ref)(unsigned) const = &mapnik::feature_impl::get_geometry;
+mapnik::geometry_type const& (mapnik::feature_impl::*get_geometry_by_const_ref)(std::size_t) const = &mapnik::feature_impl::get_geometry;
 boost::ptr_vector<mapnik::geometry_type> const& (mapnik::feature_impl::*get_paths_by_const_ref)() const = &mapnik::feature_impl::paths;
 
 void feature_add_geometries_from_wkb(mapnik::feature_impl &feature, std::string wkb)
@@ -64,6 +67,18 @@ void feature_add_geometries_from_wkt(mapnik::feature_impl &feature, std::string
     if (!result) throw std::runtime_error("Failed to parse WKT");
 }
 
+mapnik::feature_ptr from_geojson_impl(std::string const& json, mapnik::context_ptr const& ctx)
+{
+    mapnik::transcoder tr("utf8");
+    mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx,1));
+    mapnik::json::feature_parser<std::string::const_iterator> parser(tr);
+    if (!parser.parse(json.begin(), json.end(), *feature))
+    {
+        throw std::runtime_error("Failed to parse geojson feature");
+    }
+    return feature;
+}
+
 std::string feature_to_geojson(mapnik::feature_impl const& feature)
 {
     std::string json;
@@ -232,5 +247,7 @@ void export_feature()
         .def("__len__", &mapnik::feature_impl::size)
         .def("context",&mapnik::feature_impl::context)
         .def("to_geojson",&feature_to_geojson)
+        .def("from_geojson",from_geojson_impl)
+        .staticmethod("from_geojson")
         ;
 }

include/mapnik/feature.hpp

@@ -211,17 +211,17 @@ public:
         geom_cont_.push_back(geom);
     }
 
-    unsigned num_geometries() const
+    std::size_t num_geometries() const
     {
         return geom_cont_.size();
     }
 
-    geometry_type const& get_geometry(unsigned index) const
+    geometry_type const& get_geometry(std::size_t index) const
     {
         return geom_cont_[index];
     }
 
-    geometry_type& get_geometry(unsigned index)
+    geometry_type& get_geometry(std::size_t index)
     {
         return geom_cont_[index];
     }

include/mapnik/memory_featureset.hpp

@@ -76,7 +76,7 @@ public:
                 }
                 else
                 {
-                    for (unsigned i=0; i<(*pos_)->num_geometries();++i)
+                    for (std::size_t i=0; i<(*pos_)->num_geometries();++i)
                     {
                         geometry_type & geom = (*pos_)->get_geometry(i);
                         if (bbox_.intersects(geom.envelope()))

src/agg/process_building_symbolizer.cpp

@@ -86,7 +86,7 @@ void agg_renderer<T>::process(building_symbolizer const& sym,
         height = result.to_double() * scale_factor_;
     }
 
-    for (unsigned i=0;i<feature.num_geometries();++i)
+    for (std::size_t i=0;i<feature.num_geometries();++i)
     {
         geometry_type const& geom = feature.get_geometry(i);
         if (geom.size() > 2)

src/agg/process_debug_symbolizer.cpp

@@ -63,7 +63,7 @@ void agg_renderer<T>::process(debug_symbolizer const& sym,
     }
     else if (mode == DEBUG_SYM_MODE_VERTEX)
     {
-        for (unsigned i=0; i<feature.num_geometries(); ++i)
+        for (std::size_t i=0; i<feature.num_geometries(); ++i)
         {
             geometry_type const& geom = feature.get_geometry(i);
             double x;

src/agg/process_point_symbolizer.cpp

@@ -74,7 +74,7 @@ void agg_renderer<T>::process(point_symbolizer const& sym,
         agg::trans_affine recenter_tr = recenter * tr;
         box2d<double> label_ext = bbox * recenter_tr * agg::trans_affine_scaling(scale_factor_);
 
-        for (unsigned i=0; i<feature.num_geometries(); ++i)
+        for (std::size_t i=0; i<feature.num_geometries(); ++i)
         {
             geometry_type const& geom = feature.get_geometry(i);
             double x;

src/build.py

@@ -201,6 +201,7 @@ source = Split(
     json/geometry_grammar.cpp
     json/geometry_parser.cpp
     json/feature_grammar.cpp
+    json/feature_parser.cpp
     json/feature_collection_parser.cpp
     json/geojson_generator.cpp
     processed_text.cpp

src/cairo_renderer.cpp

@@ -354,7 +354,7 @@ void cairo_renderer_base::process(building_symbolizer const& sym,
         height = result.to_double() * scale_factor_;
     }
 
-    for (unsigned i = 0; i < feature.num_geometries(); ++i)
+    for (std::size_t i = 0; i < feature.num_geometries(); ++i)
     {
         geometry_type const& geom = feature.get_geometry(i);
 
@@ -673,7 +673,7 @@ void cairo_renderer_base::process(point_symbolizer const& sym,
         agg::trans_affine recenter_tr = recenter * tr;
         box2d<double> label_ext = bbox * recenter_tr * agg::trans_affine_scaling(scale_factor_);
 
-        for (unsigned i = 0; i < feature.num_geometries(); ++i)
+        for (std::size_t i = 0; i < feature.num_geometries(); ++i)
         {
             geometry_type const& geom = feature.get_geometry(i);
             double x;
@@ -760,7 +760,7 @@ void cairo_renderer_base::process(line_pattern_symbolizer const& sym,
     pattern.set_filter(CAIRO_FILTER_BILINEAR);
     context_.set_line_width(height * scale_factor_);
 
-    for (unsigned i = 0; i < feature.num_geometries(); ++i)
+    for (std::size_t i = 0; i < feature.num_geometries(); ++i)
     {
         geometry_type & geom = feature.get_geometry(i);
 

src/grid/process_building_symbolizer.cpp

@@ -73,7 +73,7 @@ void grid_renderer<T>::process(building_symbolizer const& sym,
         height = result.to_double() * scale_factor_;
     }
 
-    for (unsigned i=0;i<feature.num_geometries();++i)
+    for (std::size_t i=0;i<feature.num_geometries();++i)
     {
         geometry_type & geom = feature.get_geometry(i);
         if (geom.size() > 2)

src/grid/process_line_pattern_symbolizer.cpp

@@ -62,7 +62,7 @@ void grid_renderer<T>::process(line_pattern_symbolizer const& sym,
     // TODO - actually handle image dimensions
     int stroke_width = 2;
 
-    for (unsigned i=0;i<feature.num_geometries();++i)
+    for (std::size_t i=0;i<feature.num_geometries();++i)
     {
         geometry_type & geom = feature.get_geometry(i);
         if (geom.size() > 1)

src/grid/process_point_symbolizer.cpp

@@ -76,7 +76,7 @@ void grid_renderer<T>::process(point_symbolizer const& sym,
         agg::trans_affine recenter_tr = recenter * tr;
         box2d<double> label_ext = bbox * recenter_tr * agg::trans_affine_scaling(scale_factor_) ;
 
-        for (unsigned i=0; i<feature.num_geometries(); ++i)
+        for (std::size_t i=0; i<feature.num_geometries(); ++i)
         {
             geometry_type const& geom = feature.get_geometry(i);
             double x;

src/memory_datasource.cpp

@@ -42,7 +42,7 @@ struct accumulate_extent
 
     void operator() (feature_ptr feat)
     {
-        for (unsigned i=0;i<feat->num_geometries();++i)
+        for (std::size_t i=0;i<feat->num_geometries();++i)
         {
             geometry_type & geom = feat->get_geometry(i);
             if ( first_ )

src/svg/output/process_symbolizers.cpp

@@ -71,7 +71,7 @@ bool svg_renderer<OutputIterator>::process(rule::symbolizers const& syms,
     if (process_path)
     {
         // generate path output for each geometry of the current feature.
-        for(unsigned i=0; i<feature.num_geometries(); ++i)
+        for(std::size_t i=0; i<feature.num_geometries(); ++i)
         {
             geometry_type & geom = feature.get_geometry(i);
             if(geom.size() > 0)

src/symbolizer_helpers.cpp

@@ -211,8 +211,8 @@ template <typename FaceManagerT, typename DetectorT>
 void text_symbolizer_helper<FaceManagerT, DetectorT>::initialize_geometries()
 {
     bool largest_box_only = false;
-    unsigned num_geom = feature_.num_geometries();
-    for (unsigned i=0; i<num_geom; ++i)
+    std::size_t num_geom = feature_.num_geometries();
+    for (std::size_t i=0; i<num_geom; ++i)
     {
         geometry_type const& geom = feature_.get_geometry(i);
 

tests/python_tests/geometry_io_test.py

@@ -6,6 +6,11 @@ from utilities import execution_path, run_all
 import mapnik
 from binascii import unhexlify
 
+try:
+    import json
+except ImportError:
+    import simplejson as json
+
 def setup():
     # All of the paths used are relative, if we run the tests
     # from another directory we need to chdir()
@@ -222,6 +227,17 @@ def test_wkt_collection_flattening():
 #        except RuntimeError, e:
 #            raise RuntimeError('%s %s' % (e, wkt))
 
+def test_creating_feature_from_geojson():
+    json_feat = {
+      "type": "Feature",
+      "geometry": {"type": "Point", "coordinates": [-122,48]},
+      "properties": {"name": "value"}
+    }
+    ctx = mapnik.Context()
+    feat = mapnik.Feature.from_geojson(json.dumps(json_feat),ctx)
+    eq_(feat.id(),1)
+    eq_(feat['name'],u'value')
+
 if __name__ == "__main__":
     setup()
     run_all(eval(x) for x in dir() if x.startswith("test_"))