osm2pgsql-expire: Expire type=boundary relations as multipolygons

You can always use --mode=boundary_only to switch back to boundary only
interepretation.

So type=boundary is now treated exactly like type=multipolygon.

Also adds more information to man page.

Author: joto

man/osm2pgsql-expire.1

@@ -1,79 +1,102 @@
 .TH "OSM2PGSQL" "1" "2.2.0" "" ""
 .SH NAME
-osm2pgsql\-expire \- Visualize expire output
+.PP
+osm2pgsql-expire - Visualize expire output
 .SH SYNOPSIS
-\f[B]osm2pgsql\-expire\f[R] [\f[I]OPTIONS\f[R]] \f[I]OSM\-FILE\f[R] (1)
-\f[B]osm2pgsql\-expire\f[R] \f[I]TILES\-FILE\f[R] (2)
+.PP
+\f[B]osm2pgsql-expire\f[R] [\f[I]OPTIONS\f[R]] \f[I]OSM-FILE\f[R] (1)
+\f[B]osm2pgsql-expire\f[R] \f[I]TILES-FILE\f[R] (2)
 .SH DESCRIPTION
+.PP
 \f[B]This command is currently experimental.\f[R]
 .PP
 The expire command can be used for two things:
 .IP "1." 3
 \f[B]To check what tiles some OSM data is in.\f[R] If an
-\f[I]OSM\-FILE\f[R] is specified osm2pgsql\-expire will calculate the
+\f[I]OSM-FILE\f[R] is specified osm2pgsql-expire will calculate the
 tiles covering the objects in that file.
 Note that the file must not be a change file but a regular OSM data
 file!
 Output is, by default, a tile file, but GeoJSON is also possible.
+Covering tiles are only calculated for tagged objects.
 .IP "2." 3
-\f[B]Visualize tile list.\f[R] If a \f[I]TILE\-FILE\f[R] (presumably
+\f[B]Visualize tile list.\f[R] If a \f[I]TILE-FILE\f[R] (presumably
 generated by osm2pgsql) is specified, a GeoJSON file is generated
 showing all mentioned tiles.
 In this mode all command line options are ignored.
 .PP
 Read the \f[I]Expire\f[R] chapter of the osm2pgsql manual
 (https://osm2pgsql.org/doc/manual.html#expire) for details on how to
-interpret the \f[CR]\-m, \[rs]\-\-mode\f[R] and
-\f[CR]\[rs]\-\-full\-area\-limit\f[R] options.
+interpret the \f[V]-m, \[rs]--mode\f[R] and
+\f[V]\[rs]--full-area-limit\f[R] options.
+.SH GEOMETRY GENERATION
+.PP
+To calculate the tiles covering the specified OSM data in mode (1), a
+geometry has to be generated first for each object.
+This works as follow:
+.IP \[bu] 2
+For nodes a point geometry will be generated.
+.IP \[bu] 2
+For closed ways a polygon geometry will be generated, for non-closed
+ways a linestring geometry.
+If a generated polygon is not valid, the program will fall back to a
+linestring.
+If neither a valid polygon nor a valid linestring can be generated the
+object is ignored.
+.IP \[bu] 2
+For relations a geometry is generated based on the \f[V]type\f[R] tag.
+For types \f[V]multipolygon\f[R] and \f[V]boundary\f[R], a multipolygon
+geometry is created, for types \f[V]route\f[R] and
+\f[V]multilinestring\f[R] a multilinestring geometry is created, for all
+other types a geometry collection is created.
+.PP
+Note that for (multi)polygons it depends on the command line options
+--mode and --full-area-limit whether the tiles calculation is based on
+the area or the boundary of the (multi)polygons.
 .SH OPTIONS
+.PP
 This program follows the usual GNU command line syntax, with long
-options starting with two dashes (\f[CR]\-\-\f[R]).
+options starting with two dashes (\f[V]--\f[R]).
 Mandatory arguments to long options are mandatory for short options too.
 .SH MAIN OPTIONS
 .TP
-\-b, \-\-buffer=VALUE
+-b, --buffer=VALUE
 Set buffer size around geometry relative to tile size.
 Example: Set to 0.1 for a buffer that\[cq]s 10% of the tile size.
 .TP
-\-f, \-\-format=FORMAT
+-f, --format=FORMAT
 Output format.
 Options are `tiles' (default) or `geojson'.
 The GeoJSON output uses the Web Mercator projection (EPSG:3857) which is
 supported by many programs although, strictly speaking, it is not
 allowed by the GeoJSON spec.
 .TP
-\-\-full\-area\-limit=VALUE
+--full-area-limit=VALUE
 Set full area limit.
 .TP
-\-m, \-\-mode=MODE
+-m, --mode=MODE
 Set expire mode.
-One of \f[CR]boundary_only\f[R], \f[CR]full_area\f[R] (default), and
-\f[CR]hybrid\f[R].
+One of \f[V]boundary_only\f[R], \f[V]full_area\f[R] (default), and
+\f[V]hybrid\f[R].
 .TP
-\-z, \-\-zoom=ZOOM
+-z, --zoom=ZOOM
 Zoom level on which to calculate tiles.
 .SH HELP/VERSION OPTIONS
 .TP
-\-h, \-\-help
+-h, --help
 Print help.
 .TP
-\-V, \-\-version
+-V, --version
 Print osm2pgsql version.
 .SH LOGGING OPTIONS
 .TP
-\-\-log\-level=LEVEL
+--log-level=LEVEL
 Set log level (`debug', `info' (default), `warn', or `error').
 .SH SEE ALSO
 .IP \[bu] 2
-\c
-.UR https://osm2pgsql.org
-osm2pgsql website
-.UE \c
+osm2pgsql website (https://osm2pgsql.org)
 .IP \[bu] 2
-\c
-.UR https://osm2pgsql.org/doc/manual.html
-osm2pgsql manual
-.UE \c
+osm2pgsql manual (https://osm2pgsql.org/doc/manual.html)
 .IP \[bu] 2
 \f[B]osm2pgsql\f[R](1)
 .IP \[bu] 2

man/osm2pgsql-expire.md

@@ -16,7 +16,8 @@ The expire command can be used for two things:
 1. **To check what tiles some OSM data is in.** If an *OSM-FILE* is specified
    osm2pgsql-expire will calculate the tiles covering the objects in that file.
    Note that the file must not be a change file but a regular OSM data file!
-   Output is, by default, a tile file, but GeoJSON is also possible.
+   Output is, by default, a tile file, but GeoJSON is also possible. Covering
+   tiles are only calculated for tagged objects.
 2. **Visualize tile list.** If a *TILE-FILE* (presumably generated by osm2pgsql)
    is specified, a GeoJSON file is generated showing all mentioned tiles. In
    this mode all command line options are ignored.
@@ -25,6 +26,25 @@ Read the *Expire* chapter of the osm2pgsql manual
 (https://osm2pgsql.org/doc/manual.html#expire) for details on how to
 interpret the `-m, \--mode` and `\--full-area-limit` options.
 
+# GEOMETRY GENERATION
+
+To calculate the tiles covering the specified OSM data in mode (1), a geometry
+has to be generated first for each object. This works as follow:
+
+* For nodes a point geometry will be generated.
+* For closed ways a polygon geometry will be generated, for non-closed ways
+  a linestring geometry. If a generated polygon is not valid, the program
+  will fall back to a linestring. If neither a valid polygon nor a valid
+  linestring can be generated the object is ignored.
+* For relations a geometry is generated based on the `type` tag. For types
+  `multipolygon` and `boundary`, a multipolygon geometry is created, for types
+  `route` and `multilinestring` a multilinestring geometry is created, for
+  all other types a geometry collection is created.
+
+Note that for (multi)polygons it depends on the command line options \--mode
+and \--full-area-limit whether the tiles calculation is based on the area or
+the boundary of the (multi)polygons.
+
 # OPTIONS
 
 This program follows the usual GNU command line syntax, with long options

src/osm2pgsql-expire.cpp

@@ -189,7 +189,7 @@ void output_expire_t::relation_add(osmium::Relation const &relation)
     osmium::memory::Buffer tmp_buffer{1024,
                                       osmium::memory::Buffer::auto_grow::yes};
     geom::geometry_t geom;
-    if (type == "multipolygon") {
+    if (type == "multipolygon" || type == "boundary") {
         log_debug("Creating multipolygon from relation {}...", relation.id());
         geom::create_multipolygon(&geom, relation, buffer, &tmp_buffer);
     } else if (type == "route" || type == "multilinestring") {