Merge pull request #1777 from iboates/add_length

length for flex output

Author: lonvia

src/flex-lua-geom.cpp

@@ -69,6 +69,18 @@ static int geom_area(lua_State *lua_state)
     return 1;
 }
 
+static int geom_length(lua_State *lua_state)
+{
+    auto const *const input_geometry = unpack_geometry(lua_state);
+    try {
+        lua_pushnumber(lua_state, geom::length(*input_geometry));
+    } catch (...) {
+        return luaL_error(lua_state, "Unknown error in 'length()'.\n");
+    }
+
+    return 1;
+}
+
 static int geom_centroid(lua_State *lua_state)
 {
     auto const *const input_geometry = unpack_geometry(lua_state);
@@ -239,6 +251,7 @@ void init_geometry_class(lua_State *lua_state)
     lua_pushvalue(lua_state, -1);
     lua_setfield(lua_state, -2, "__index");
     luaX_add_table_func(lua_state, "area", geom_area);
+    luaX_add_table_func(lua_state, "length", geom_length);
     luaX_add_table_func(lua_state, "centroid", geom_centroid);
     luaX_add_table_func(lua_state, "geometry_n", geom_geometry_n);
     luaX_add_table_func(lua_state, "geometry_type", geom_geometry_type);

src/geom-functions.cpp

@@ -7,8 +7,8 @@
  * For a full list of authors see the git log.
  */
 
-#include "geom-boost-adaptor.hpp"
 #include "geom-functions.hpp"
+#include "geom-boost-adaptor.hpp"
 
 #include <algorithm>
 #include <cmath>
@@ -378,6 +378,22 @@ double area(geometry_t const &geom)
     return std::abs(total);
 }
 
+double length(geometry_t const &geom)
+{
+    return geom.visit(overloaded{
+        [&](geom::nullgeom_t const & /*input*/) { return 0.0; },
+        [&](geom::collection_t const &input) {
+            double total = 0.0;
+            for (auto const &item : input) {
+                total += length(item);
+            }
+            return total;
+        },
+        [&](auto const &input) {
+            return static_cast<double>(boost::geometry::length(input));
+        }});
+}
+
 namespace {
 
 class split_visitor
@@ -414,7 +430,7 @@ class split_visitor
 
 } // anonymous namespace
 
-std::vector<geometry_t> split_multi(geometry_t&& geom, bool split_multi)
+std::vector<geometry_t> split_multi(geometry_t &&geom, bool split_multi)
 {
     std::vector<geometry_t> output;
 

src/geom-functions.hpp

@@ -41,7 +41,7 @@ point_t interpolate(point_t p1, point_t p2, double frac) noexcept;
  * \pre \code !list.empty() \endcode
  */
 template <typename FUNC>
-void for_each_segment(point_list_t const &list, FUNC&& func)
+void for_each_segment(point_list_t const &list, FUNC &&func)
 {
     assert(!list.empty());
     auto it = list.cbegin();
@@ -158,6 +158,16 @@ double area(geometry_t const &geom);
  */
 std::vector<geometry_t> split_multi(geometry_t &&geom, bool split_multi = true);
 
+/**
+ * Calculate length of geometry.
+ * For geometry types other than linestring or multilinestring this will always
+ * return 0.
+ *
+ * \param geom Input geometry.
+ * \returns Length.
+ **/
+double length(geometry_t const &geom);
+
 /**
  * Reverses the order of the vertices in geometry.
  *

tests/test-geom-collections.cpp

@@ -25,6 +25,7 @@ TEST_CASE("geometry collection with point", "[NoDB]")
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE_THROWS(centroid(geom));
     REQUIRE(geometry_n(geom, 1) == geom::geometry_t{geom::point_t{1, 1}});
 }
@@ -41,6 +42,7 @@ TEST_CASE("geometry collection with several geometries", "[NoDB]")
     REQUIRE(geometry_type(geom) == "GEOMETRYCOLLECTION");
     REQUIRE(num_geometries(geom) == 3);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(1.41421));
     REQUIRE_THROWS(centroid(geom));
     REQUIRE(geometry_n(geom, 1) == geom::geometry_t{geom::point_t{1, 1}});
     REQUIRE(geometry_n(geom, 2) ==
@@ -68,6 +70,7 @@ TEST_CASE("create_collection from OSM data", "[NoDB]")
     REQUIRE(c[2] == geom::geometry_t{geom::linestring_t{{10, 10}, {10, 20}}});
 
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(14.0));
     REQUIRE_THROWS(centroid(geom));
 }
 

tests/test-geom-linestrings.cpp

@@ -44,6 +44,7 @@ TEST_CASE("line geometry", "[NoDB]")
 
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(1.41421));
     REQUIRE(geometry_type(geom) == "LINESTRING");
     REQUIRE(centroid(geom) == geom::geometry_t{geom::point_t{1.5, 1.5}});
     REQUIRE(geometry_n(geom, 1) == geom);
@@ -74,6 +75,7 @@ TEST_CASE("create_linestring from OSM data", "[NoDB]")
     REQUIRE(geometry_type(geom) == "LINESTRING");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(1.41421));
     REQUIRE(geom.get<geom::linestring_t>() ==
             geom::linestring_t{{1, 1}, {2, 2}});
     REQUIRE(centroid(geom) == geom::geometry_t{geom::point_t{1.5, 1.5}});

tests/test-geom-multilinestrings.cpp

@@ -32,6 +32,7 @@ TEST_CASE("create_multilinestring with single line", "[NoDB]")
     REQUIRE(geometry_type(geom) == "MULTILINESTRING");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(1.0));
     auto const &ml = geom.get<geom::multilinestring_t>();
     REQUIRE(ml.num_geometries() == 1);
     REQUIRE(ml[0] == expected);
@@ -56,6 +57,7 @@ TEST_CASE("create_multilinestring with single line and no force_multi",
     REQUIRE(geometry_type(geom) == "LINESTRING");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(1.0));
     auto const &l = geom.get<geom::linestring_t>();
     REQUIRE(l.num_geometries() == 1);
     REQUIRE(l == expected);

tests/test-geom-multipoints.cpp

@@ -30,6 +30,7 @@ TEST_CASE("multipoint_t with a single point", "[NoDB]")
     REQUIRE(geometry_type(geom) == "MULTIPOINT");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE(reverse(geom) == geom);
     REQUIRE(centroid(geom) == geom::geometry_t{std::move(point)});
 
@@ -52,6 +53,7 @@ TEST_CASE("multipoint_t with several points", "[NoDB]")
     REQUIRE(geometry_type(geom) == "MULTIPOINT");
     REQUIRE(num_geometries(geom) == 3);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE(reverse(geom) == geom);
     REQUIRE(centroid(geom) == geom::geometry_t{geom::point_t{2, 1}});
 

tests/test-geom-multipolygons.cpp

@@ -26,6 +26,7 @@ TEST_CASE("multipolygon geometry with single outer, no inner", "[NoDB]")
     REQUIRE(geometry_type(geom) == "MULTIPOLYGON");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(1.0));
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE(centroid(geom) == geom::geometry_t{geom::point_t{0.5, 0.5}});
     REQUIRE(geometry_n(geom, 1) ==
             geom::geometry_t{geom::polygon_t{
@@ -52,6 +53,7 @@ TEST_CASE("multipolygon geometry with two polygons", "[NoDB]")
     REQUIRE(geometry_type(geom) == "MULTIPOLYGON");
     REQUIRE(num_geometries(geom) == 2);
     REQUIRE(area(geom) == Approx(9.0));
+    REQUIRE(length(geom) == Approx(0.0));
 }
 
 TEST_CASE("create_multipolygon creates simple polygon from OSM data", "[NoDB]")
@@ -67,6 +69,7 @@ TEST_CASE("create_multipolygon creates simple polygon from OSM data", "[NoDB]")
     REQUIRE(geometry_type(geom) == "POLYGON");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(1.0));
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE(
         geom.get<geom::polygon_t>() ==
         geom::polygon_t{geom::ring_t{{1, 1}, {2, 1}, {2, 2}, {1, 2}, {1, 1}}});
@@ -87,6 +90,7 @@ TEST_CASE("create_multipolygon from OSM data", "[NoDB]")
     REQUIRE(geometry_type(geom) == "MULTIPOLYGON");
     REQUIRE(num_geometries(geom) == 2);
     REQUIRE(area(geom) == Approx(51.0));
+    REQUIRE(length(geom) == Approx(0.0));
 }
 
 TEST_CASE("create_multipolygon from OSM data without locations", "[NoDB]")
@@ -111,7 +115,8 @@ TEST_CASE("create_multipolygon from invalid OSM data (single node)", "[NoDB]")
     REQUIRE(geom.is_null());
 }
 
-TEST_CASE("create_multipolygon from invalid OSM data (way node closed)", "[NoDB]")
+TEST_CASE("create_multipolygon from invalid OSM data (way node closed)",
+          "[NoDB]")
 {
     test_buffer_t buffer;
     buffer.add_way("w20 Nn1x1y1,n2x2y2");
@@ -122,7 +127,8 @@ TEST_CASE("create_multipolygon from invalid OSM data (way node closed)", "[NoDB]
     REQUIRE(geom.is_null());
 }
 
-TEST_CASE("create_multipolygon from invalid OSM data (self-intersection)", "[NoDB]")
+TEST_CASE("create_multipolygon from invalid OSM data (self-intersection)",
+          "[NoDB]")
 {
     test_buffer_t buffer;
     buffer.add_way("w20 Nn1x1y1,n2x1y2,n3x2y1,n4x2y2");

tests/test-geom-null.cpp

@@ -19,6 +19,7 @@ TEST_CASE("null geometry", "[NoDB]")
 
     REQUIRE(num_geometries(geom) == 0);
     REQUIRE(area(geom) == 0.0);
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE(geometry_type(geom) == "NULL");
     REQUIRE(centroid(geom).is_null());
     REQUIRE(geometry_n(geom, 1).is_null());

tests/test-geom-points.cpp

@@ -52,6 +52,7 @@ TEST_CASE("create_point from OSM data", "[NoDB]")
     REQUIRE(geometry_type(geom) == "POINT");
     REQUIRE(num_geometries(geom) == 1);
     REQUIRE(area(geom) == Approx(0.0));
+    REQUIRE(length(geom) == Approx(0.0));
     REQUIRE(centroid(geom) == geom::geometry_t{geom::point_t{1.1, 2.2}});
     REQUIRE(geometry_n(geom, 1) == geom);
     REQUIRE(reverse(geom) == geom);