[Mapserver-users] known issue: no results with QueryByPoint (Mapserver 3.7 P

[Andreas Hirner]

Hello,

I had a similar problem. You need a CLASS section in your layer. Secondly 
the status of your layer in the map file is set "OFF". Switch it to "ON" and 
you might by able to obtain results.

Cheers Andreas

>From: Michael Härtel <mhaerte1 at gwdg.de>
>To: mapserver-users at lists.gis.umn.edu
>Subject: [Mapserver-users] known issue: no results with QueryByPoint 
>(Mapserver 3.7 PHP mapscript)
>Date: Wed, 21 May 2003 13:41:33 +0200
>
>Hello All!
>
>There are many references to articles about the problem that no results are 
>returned by QueryByPoint.
>i' ve read all of them but i still can't figure out why i get no results.
>
>This is what i have:
>
>1.) A Query Layer ($querylayer) with a template file:
>
>object(layer)(35) { ["_handle_"]=>  resource(50) of type (layerObj) 
>["_map_handle_"]=>  resource(1) of type (mapObj) ["numclasses"]=> int(0) 
>["index"]=>  int(7) ["status"]=>  int(0) ["classitem"]=> string(0) "" 
>["name"]=>  string(11) "WRS-2_frame" ["group"]=>  string(0) "" ["data"]=>  
>string(9) "wrs2/wrs2" ["type"]=>  int(2) ["tolerance"]=>  float(3) 
>["toleranceunits"]=>  int(6) ["symbolscale"]=>  float(-1) ["minscale"]=>  
>float(-1) ["maxscale"]=>  float(-1) ["labelminscale"]=>  float(-1) 
>["labelmaxscale"]=>  float(-1) ["maxfeatures"]=>  int(-1) ["transform"]=>  
>int(1) ["labelcache"]=>  int(1) ["postlabelcache"]=> int(0) ["labelitem"]=> 
>  string(0) "" ["labelsizeitem"]=>  string(0) "" ["labelangleitem"]=>  
>string(0) "" ["tileitem"]=>  string(8) "location" ["tileindex"]=>  
>string(0) "" ["header"]=>  string(32) "H:\_webroot_\mapserv_header.html" 
>["footer"]=>  string(32) "H:\_webroot_\mapserv_footer.html" 
>["connection"]=>  string(0) "" ["connectiontype"]=>  int(1) 
>["filteritem"]=>  string(0) "" ["template"]=>  string(40) 
>"H:\_webroot_\mapserv_query_template.html" ["transparency"]=>  int(0) 
>["styleitem"]=>  string(0) "" ["offsite"]=> object(color)(4) { 
>["_handle_"]=>  resource(51) of type (Unknown) ["red"]=>  int(-1) 
>["green"]=>  int(-1) ["blue"]=>  int(-1) } }
>
>2.) A Point Object with geographic coordinates:
>
>object(point)(4) { ["_handle_"]=>  resource(52) of type (Unknown) ["x"]=>  
>float(9.85) ["y"]=>  float(50.9) ["m"]=>  float(50.9) }
>
>3.) A call to Query function (with tolerance set in map file):
>
>$query=$querylayer->QueryByPoint($my_point,MS_MULTIPLE,-1);
>
>4. The entry of the query-layer in the map file:
>
>LAYER	#wrs2
>NAME "WRS-2_frame"
>
>	PROJECTION
>		proj=longlat
>		ellps=WGS84
>		datum=WGS84
>		no_defs
>	END
>
>   DATA "wrs2/wrs2"
>   STATUS OFF
>   TYPE POLYGON
>
>   TOLERANCEUNITS kilometers
>   TOLERANCE 5
>   DUMP TRUE
>
>   HEADER "H:\_webroot_\mapserv_header.html"
>   TEMPLATE "H:\_webroot_\mapserv_query_template.html"
>   FOOTER "H:\_webroot_\mapserv_footer.html"
>
>END # layer wrs2
>
>4.) The map i use is a world map with these parameters:
>
>EXTENT -180.000000 -90.000000 180.000000 90.000000
>SIZE 600 300
>
>UNITS DD
>
>PROJECTION
>	proj=longlat
>	ellps=WGS84
>	datum=WGS84
>	no_defs
>END
>
>What i get is the common error message:
>
>"Warning: MapServer Error in msQueryByPoint(): No matching record(s) found"
>
>The query layer extends over the whole map.
>
>These actions were already performed without any change to the result:
>
>1. changed tolerance to 1 in QueryByPoint function call
>2. MS_SINGLE mode tried instead of MS_MULTIPLE
>3. Pixel coordinates in Point object used instead of geographic coordinates
>
>
>So what the **** am i doing wrong? Unfortunately i can´t find an example of 
>a template file where i could look how the results can be printed.
>But i guess i need a result first and THEN there may occur errors 
>concerning a misconfiguration because of a missing/wrong template file.
>
>Do i actually need a template file if i use mapserver 3.7 with mapscript? 
>Or is it only needed by the simple CGI version?
>
>Thanks for any reply, i'm glad to know that there are some real freaks out 
>there :)
>
>(im looking forward to a documentation about how to perform queries with 
>mapserver 3.7 and mapscript).
>
>----------------------------------------------------------------------
>Michael Härtel
>Georg-August University Goettingen
>Department of Geography
>Cartography, GIS & Remote Sensing Section
>project Notebook University, Internet Map Service
>Goldschmidtstr. 5                           Tel.: +49 (0)551/39-12671
>37077 Goettingen                            Fax : +49 (0)551/39-8020
>http://www.geogr.uni-goettingen.de/kuf/
>
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