Allow a limit to be set on expiry of line segments

man/osm2pgsql.1

@@ -313,6 +313,9 @@ Create a tile expiry list.
 -o, --expire-output=FILENAME
 Output file name for expired tiles list.
 .TP
+--expire-segment-length=SIZE
+Max length for a line segment to be expired.
+.TP
 --expire-bbox-size=SIZE
 Max size for a polygon to expire the whole polygon, not just the
 boundary.

man/osm2pgsql.md

@@ -278,6 +278,9 @@ mandatory for short options too.
 -o, \--expire-output=FILENAME
 :   Output file name for expired tiles list.
 
+\--expire-segment-length=SIZE
+:   Max length for a line segment to be expired.
+
 \--expire-bbox-size=SIZE
 :   Max size for a polygon to expire the whole polygon, not just the boundary.
 

src/command-line-parser.cpp

@@ -460,6 +460,12 @@ options_t parse_command_line(int argc, char *argv[])
     // Expire options
     // ----------------------------------------------------------------------
 
+    // --expire-segment-length
+    app.add_option("--expire-segment-length", options.expire_tiles_max_segment)
+        ->description("Max length for a line segment to be expired (default: no limit).")
+        ->type_name("SIZE")
+        ->group("Expire options");
+
     // --expire-bbox-size
     app.add_option("--expire-bbox-size", options.expire_tiles_max_bbox)
         ->description("Max size for a polygon to expire the whole polygon, not "

src/expire-config.hpp

@@ -33,6 +33,11 @@ struct expire_config_t
     /// Buffer around expired feature as fraction of the tile size.
     double buffer = 0.1;
 
+    /**
+     * Maximum length of a line segment that will be expired.
+     */
+    double line_segment_limit = 0.0;
+
     /**
      * Maximum width/heigth of bbox of a (multi)polygon before hybrid mode
      * expiry switches from full-area to boundary-only expire.

src/expire-tiles.cpp

@@ -156,6 +156,11 @@ void expire_tiles::from_line_segment(geom::point_t const &a,
                                      geom::point_t const &b,
                                      expire_config_t const &expire_config)
 {
+    if (expire_config.line_segment_limit > 0.0 &&
+        distance(a, b) > expire_config.line_segment_limit) {
+        return;
+    }
+
     auto tilec_a = coords_to_tile(a);
     auto tilec_b = coords_to_tile(b);
 

src/flex-lua-table.cpp

@@ -271,6 +271,15 @@ static void parse_and_set_expire_options(lua_State *lua_state,
             throw fmt_error("Unknown expire mode '{}'.", mode);
         }
 
+        lua_getfield(lua_state, -1, "line_segment_limit");
+        if (lua_isnumber(lua_state, -1)) {
+            config.line_segment_limit = lua_tonumber(lua_state, -1);
+        } else if (!lua_isnil(lua_state, -1)) {
+            throw std::runtime_error{"Optional expire field 'line_segment_limit' "
+                                     "must contain a number."};
+        }
+        lua_pop(lua_state, 1); // ""line_segment_limit"
+
         lua_getfield(lua_state, -1, "full_area_limit");
         if (lua_isnumber(lua_state, -1)) {
             if (config.mode != expire_mode::hybrid) {

src/options.hpp

@@ -95,6 +95,9 @@ struct options_t
 
     std::shared_ptr<reprojection> projection; ///< SRS of projection
 
+    /// Max length of line segment that will be expired
+    double expire_tiles_max_segment = 0.0;
+
     /// Max bbox size in either dimension to expire full bbox for a polygon
     double expire_tiles_max_bbox = 20000.0;
 

src/output-flex.cpp

@@ -1189,6 +1189,7 @@ output_flex_t::output_flex_t(std::shared_ptr<middle_query_t> const &mid,
             if (table.has_geom_column() && table.geom_column().srid() == 3857) {
                 expire_config_t config{};
                 config.expire_output = m_expire_outputs->size() - 1;
+                config.line_segment_limit = options.expire_tiles_max_segment;
                 if (options.expire_tiles_max_bbox > 0.0) {
                     config.mode = expire_mode::hybrid;
                     config.full_area_limit = options.expire_tiles_max_bbox;

src/output-pgsql.cpp

@@ -438,6 +438,7 @@ output_pgsql_t::output_pgsql_t(std::shared_ptr<middle_query_t> const &mid,
   m_buffer(32768, osmium::memory::Buffer::auto_grow::yes),
   m_rels_buffer(1024, osmium::memory::Buffer::auto_grow::yes)
 {
+    m_expire_config.line_segment_limit = get_options()->expire_tiles_max_segment;
     m_expire_config.full_area_limit = get_options()->expire_tiles_max_bbox;
     if (get_options()->expire_tiles_max_bbox > 0.0) {
         m_expire_config.mode = expire_mode::hybrid;

tests/test-expire-from-geometry.cpp

@@ -165,6 +165,37 @@ TEST_CASE("expire linestring crossing tile boundary", "[NoDB]")
     CHECK(tile_t::from_quadkey(tiles[1], zoom) == tile_t{zoom, 2048, 2047});
 }
 
+TEST_CASE("expire linestring with long segment", "[NoDB]")
+{
+    expire_config_t expire_config;
+    expire_config.line_segment_limit = 10000;
+    expire_tiles et{zoom, defproj};
+
+    SECTION("line")
+    {
+        geom::linestring_t const line{{5000.0, 5000.0}, {15000.0, 15000.0}};
+        et.from_geometry(line, expire_config);
+    }
+
+    SECTION("geom")
+    {
+        geom::linestring_t line{{5000.0, 5000.0}, {15000.0, 15000.0}};
+        geom::geometry_t const geom{std::move(line)};
+        et.from_geometry(geom, expire_config);
+    }
+
+    SECTION("geom with check")
+    {
+        geom::linestring_t line{{5000.0, 5000.0}, {15000.0, 15000.0}};
+        geom::geometry_t geom{std::move(line)};
+        geom.set_srid(3857);
+        et.from_geometry_if_3857(geom, expire_config);
+    }
+
+    auto const tiles = et.get_tiles();
+    REQUIRE(tiles.size() == 0);
+}
+
 TEST_CASE("expire small polygon", "[NoDB]")
 {
     expire_config_t const expire_config;