Using pgr_findCloseEdges to determine gaps

Author: cvvergara

doc/src/migration.rst

@@ -68,32 +68,41 @@ For example:
 
 .. rubric:: Dead ends.
 
-Instead of counting the dead ends, determine all the dead ends of the graph.
+Instead of counting the dead ends, determine all the dead ends of the graph
+using :doc:`pgr_degree`.
+
+For example:
 
 .. literalinclude:: migration.queries
    :start-after: --analysis2
    :end-before: --analysis3
 
 .. rubric:: Potential gaps near dead ends.
 
-Instead of counting potential gaps between geometries, determine geometric
-relationships between geometries.
+Instead of counting potential gaps between geometries, determine the geometric
+gaps in the graph using :doc:`pgr_findCloseEdges`.
 
-Several PostGIS functions can be used, for example:
+For example:
 
-* `ST_ClosestPoint <https://postgis.net/docs/ST_ClosestPoint.html>`__
-* `ST_Distance <https://postgis.net/docs/ST_Distance.html>`__
+.. literalinclude:: migration.queries
+   :start-after: --analysis3
+   :end-before: --analysis4
 
 .. rubric::  Topological relationships.
 
 Instead of counting intersections, determine topological relationships between
 geometries.
 
-Several PostGIS functions can be used, for example:
+Several PostGIS functions can be used:
+`ST_Intersects <https://postgis.net/docs/ST_Intersects.html>`__,
+`ST_Crosses <https://postgis.net/docs/ST_Crosses.html>`__,
+`ST_Overlaps <https://postgis.net/docs/ST_Overlaps.html>`__, etc.
 
-* `ST_Intersects <https://postgis.net/docs/ST_Intersects.html>`__
-* `ST_Crosses <https://postgis.net/docs/ST_Crosses.html>`__
-* `ST_Overlaps <https://postgis.net/docs/ST_Overlaps.html>`__
+For example:
+
+.. literalinclude:: migration.queries
+   :start-after: --analysis4
+   :end-before: --analysis5
 
 .. migrate_pgr_analyzeGraph_end
 

doc/topology/pgr_analyzeGraph.rst

@@ -13,7 +13,7 @@
 
 |
 
-``pgr_analyzeGraph``
+``pgr_analyzeGraph`` -- Deprecated since 3.8.0
 ===============================================================================
 
 ``pgr_analyzeGraph`` — Analyzes the network topology.

docqueries/src/migration.pg

@@ -388,3 +388,16 @@ SELECT *
 FROM pgr_degree($$SELECT id, source, target FROM edges$$)
 WHERE degree = 1;
 /* --analysis3*/
+WITH
+deadends AS (
+  SELECT id,geom, (in_edges || out_edges)[1] as inhere
+  FROM vertices where array_length(in_edges || out_edges, 1) = 1),
+results AS (
+  SELECT (pgr_findCloseEdges('SELECT id, geom FROM edges WHERE id != ' || inhere , geom, 0.001)).*
+  FROM deadends)
+SELECT d.id, edge_id, distance, st_AsText(geom) AS point, st_asText(edge) edge
+FROM results JOIN deadends d USING (geom);
+/* --analysis4*/
+SELECT e1.id AS id1, e2.id AS id2
+FROM edges e1, edges e2 WHERE e1 < e2 AND st_crosses(e1.geom, e2.geom);
+/* --analysis5*/

docqueries/src/migration.result

@@ -1283,5 +1283,28 @@ WHERE degree = 1;
 (7 rows)
 
 /* --analysis3*/
+WITH
+deadends AS (
+  SELECT id,geom, (in_edges || out_edges)[1] as inhere
+  FROM vertices where array_length(in_edges || out_edges, 1) = 1),
+results AS (
+  SELECT (pgr_findCloseEdges('SELECT id, geom FROM edges WHERE id != ' || inhere , geom, 0.001)).*
+  FROM deadends)
+SELECT d.id, edge_id, distance, st_AsText(geom) AS point, st_asText(edge) edge
+FROM results JOIN deadends d USING (geom);
+ id | edge_id |     distance      |           point           |                 edge
+----+---------+-------------------+---------------------------+--------------------------------------
+  4 |      14 | 1.00008890058e-12 | POINT(1.999999999999 3.5) | LINESTRING(1.999999999999 3.5,2 3.5)
+(1 row)
+
+/* --analysis4*/
+SELECT e1.id AS id1, e2.id AS id2
+FROM edges e1, edges e2 WHERE e1 < e2 AND st_crosses(e1.geom, e2.geom);
+ id1 | id2
+-----+-----
+  13 |  18
+(1 row)
+
+/* --analysis5*/
 ROLLBACK;
 ROLLBACK