don't use geom collection, instead diff geom per feature

plugins/input/templates/helloworld/hello_featureset.cpp

@@ -11,7 +11,10 @@ hello_featureset::hello_featureset(mapnik::box2d<double> const& box, std::string
     : box_(box),
       feature_id_(1),
       tr_(new mapnik::transcoder(encoding)),
-      ctx_(std::make_shared<mapnik::context_type>()) { }
+      ctx_(std::make_shared<mapnik::context_type>()) {
+        // add known field names to attributes schema
+        ctx_->push("key");
+      }
 
 hello_featureset::~hello_featureset() { }
 
@@ -19,33 +22,38 @@ mapnik::feature_ptr hello_featureset::next()
 {
     if (feature_id_ == 1)
     {
-        // let us pretend it just has one column/attribute name
-        std::string attribute("key");
-
-        // the featureset context needs to know the field schema
-        ctx_->push(attribute);
-
         // create a new feature
         mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx_,feature_id_));
 
-        // increment the count so that we only return one feature
+        // increment the count
         ++feature_id_;
 
         // create an attribute pair of key:value
-        mapnik::value_unicode_string ustr = tr_->transcode("hello world!");
+        feature->put("key",tr_->transcode("hello world point!"));
-        feature->put(attribute,ustr);
 
-        // we need a geometry to display so just for fun here
+        // take the center of the bbox that was used to query
-        // we take the center of the bbox that was used to query
+        // to dynamically generate a fake point
-        // since we don't actually have any data to pull from...
         mapnik::coord2d center = box_.center();
 
         // create a new point geometry
         feature->set_geometry(mapnik::new_geometry::point(center.x,center.y));
 
-        // A feature usually will have just one geometry of a given type
+        // return the feature!
-        // but mapnik supports many geometries per feature of any type
+        return feature;
-        // so here we draw a line around the point
+    }
+    else if (feature_id_ == 2)
+    {
+        // create a second feature
+        mapnik::feature_ptr feature(mapnik::feature_factory::create(ctx_,feature_id_));
+
+        // increment the count
+        ++feature_id_;
+
+        // create an attribute pair of key:value
+        feature->put("key",tr_->transcode("hello world line!"));
+
+        // take the outer ring of the bbox that was used to query
+        // to dynamically generate a fake line
         mapnik::new_geometry::line_string line;
         line.reserve(4);
         line.add_coord(box_.minx(),box_.maxy());
@@ -53,8 +61,6 @@ mapnik::feature_ptr hello_featureset::next()
         line.add_coord(box_.maxx(),box_.miny());
         line.add_coord(box_.minx(),box_.miny());
         feature->set_geometry(std::move(line));
-
-        // return the feature!
         return feature;
     }