From: gemo1011 <moritzgeiger91@web.de>
Date: Tue, 26 Jun 2018 13:16:19 +0000 (+0200)
Subject: added comments and improved geOutline function
X-Git-Tag: v3.2.0~60^2~1
X-Git-Url: https://git.openstreetmap.org./nominatim.git/commitdiff_plain/1d7ed6737e1351a5ca25af485c7e51a757649d92

added comments and improved geOutline function
---

diff --git a/lib/PlaceLookup.php b/lib/PlaceLookup.php
index 270e2745..cf744929 100644
--- a/lib/PlaceLookup.php
+++ b/lib/PlaceLookup.php
@@ -538,14 +538,8 @@ class PlaceLookup
             // Get the bounding box and outline polygon
             $sSQL = 'select place_id,0 as numfeatures,st_area(geometry) as area,';
             if ($fLonReverse != null && $fLatReverse != null) {
-                $sSQL .= ' CASE WHEN (class = \'highway\') AND (ST_GeometryType(geometry) = \'ST_LineString\') THEN';
-                $sSQL .= ' ST_Y(closest_point)';
-                $sSQL .= ' ELSE ST_Y(centroid) ';
-                $sSQL .= ' END as centrelat, ';
-                $sSQL .= ' CASE WHEN (class = \'highway\') AND (ST_GeometryType(geometry) = \'ST_LineString\') THEN';
-                $sSQL .= ' ST_X(closest_point)';
-                $sSQL .= ' ELSE ST_X(centroid) ';
-                $sSQL .= ' END as centrelon, ';
+                $sSQL .= ' ST_Y(closest_point) as centrelat,';
+                $sSQL .= ' ST_X(closest_point) as centrelon,';
             } else {
                 $sSQL .= ' ST_Y(centroid) as centrelat, ST_X(centroid) as centrelon,';
             }
@@ -557,7 +551,8 @@ class PlaceLookup
             if ($this->bIncludePolygonAsText || $this->bIncludePolygonAsPoints) $sSQL .= ',ST_AsText(geometry) as astext';
             if ($fLonReverse != null && $fLatReverse != null) {
                 $sFrom = ' from (SELECT * , CASE WHEN (class = \'highway\') AND (ST_GeometryType(geometry) = \'ST_LineString\') THEN ';
-                $sFrom .=' ST_ClosestPoint(geometry, ST_SetSRID(ST_Point('.$fLatReverse.','.$fLonReverse.'),4326)) END AS closest_point';
+                $sFrom .=' ST_ClosestPoint(geometry, ST_SetSRID(ST_Point('.$fLatReverse.','.$fLonReverse.'),4326))';
+                $sFrom .=' ELSE centroid END AS closest_point';
                 $sFrom .= ' from placex where place_id = '.$iPlaceID.') as plx';
             } else {
                 $sFrom = ' from placex where place_id = '.$iPlaceID;
diff --git a/lib/ReverseGeocode.php b/lib/ReverseGeocode.php
index fbea17c5..41da2667 100644
--- a/lib/ReverseGeocode.php
+++ b/lib/ReverseGeocode.php
@@ -75,11 +75,14 @@ class ReverseGeocode
     
     protected function polygonFunctions($sPointSQL, $iMaxRank)
     {
+        // starts the nopolygonFound function if no polygon is found with the lookupPolygon function
         $oResult = null;
         
         $aPlace = $this->lookupPolygon($sPointSQL, $iMaxRank);
         if ($aPlace) {
             $oResult = new Result($aPlace['place_id']);
+        // if no polygon which contains the searchpoint is found,
+        // the noPolygonFound function searches in the country_osm_grid table for a polygon
         } elseif (!$aPlace && $iMaxRank > 4) {
             $aPlace = $this->noPolygonFound($sPointSQL, $iMaxRank);
             if ($aPlace) {
@@ -92,6 +95,7 @@ class ReverseGeocode
     protected function noPolygonFound($sPointSQL, $iMaxRank)
     {
         // searches for polygon in table country_osm_grid which contains the searchpoint
+        // and searches for the nearest place node to the searchpoint in this polygon
         $sSQL = 'SELECT * FROM country_osm_grid';
         $sSQL .= ' WHERE ST_CONTAINS (geometry, '.$sPointSQL.' )';
         
@@ -127,11 +131,14 @@ class ReverseGeocode
     
     protected function lookupPolygon($sPointSQL, $iMaxRank)
     {
+        // searches for polygon where the searchpoint is within
+        // if a polygon is found, placenodes with a higher rank are searched inside the polygon
+    
         // polygon search begins at suburb-level
         if ($iMaxRank > 25) $iMaxRank = 25;
         // no polygon search over country-level
         if ($iMaxRank < 4) $iMaxRank = 4;
-        
+        // search for polygon
         $sSQL = 'SELECT * FROM';
         $sSQL .= '(select place_id,parent_place_id,rank_address, rank_search, country_code, geometry';
         $sSQL .= ' FROM placex';
@@ -150,6 +157,7 @@ class ReverseGeocode
             'Could not determine polygon containing the point.'
         );
         if ($aPoly) {
+        // if a polygon is found, search for placenodes begins ...
             $iParentPlaceID = $aPoly['parent_place_id'];
             $iRankAddress = $aPoly['rank_address'];
             $iRankSearch = $aPoly['rank_search'];
@@ -225,7 +233,10 @@ class ReverseGeocode
 
     public function lookupPoint($sPointSQL, $bDoInterpolation = true)
     {
-        
+        // starts if the search is on POI or street level,
+        // searches for the nearest POI or street,
+        // if a street is found and a POI is searched for,
+        // the nearest POI which the found street is a parent of is choosen.
         $iMaxRank = $this->iMaxRank;
 
         // Find the nearest point
@@ -322,7 +333,7 @@ class ReverseGeocode
                 
                   // In the US we can check TIGER data for nearest housenumber
                 if (CONST_Use_US_Tiger_Data && $aPlace['country_code'] == 'us' && $this->iMaxRank >= 28) {
-                    $fSearchDiam = $aPlace['rank_search'] > 28 ? $aPlace['distance'] : 0.001;
+                    $fSearchDiam = $aPlace['rank_address'] > 28 ? $aPlace['distance'] : 0.001;
                     $sSQL = 'SELECT place_id,parent_place_id,30 as rank_search,';
                     $sSQL .= 'ST_LineLocatePoint(linegeo,'.$sPointSQL.') as fraction,';
                     $sSQL .= 'ST_distance('.$sPointSQL.', linegeo) as distance,';