queryBypoint problem - Please help

Nagu Govind lsnagu at YAHOO.COM
Sun Feb 13 03:31:59 EST 2005


Hi,
Iam using MapScript.
I want to find out the State and District name using latiudes and longitudes. My .dbf file has the following fields
1.Dst_ID
2.District
3. State

I want to get this info corresponding to my lat and long.

My map file layer is like this
---------------------
MAP
 NAME "ind"
 SIZE 500 500
 STATUS ON
 SYMBOLSET "maps/symbols/examples.sym"
 EXTENT 67 5 99 40

 SHAPEPATH "maps/data/"

    PROJECTION
  "proj=latlong"
  "datum=NAD83"
    END

 WEB
  IMAGEPATH "maps/tmp/"
  IMAGEURL "maps/"
  TEMPLATE  'maps/myind.html'
 END

QUERYMAP
  STATUS ON
  STYLE SELECTED
  COLOR 255 255 0
 END

 LAYER
  NAME "Ind"
  TYPE POLYGON
  STATUS ON
  DATA "ind_ds"
  PROJECTION
   "proj=latlong"
   "ellps=GRS80"
  END
  CLASS
   NAME "IND MAP"
   OUTLINECOLOR 0 0 0
   COLOR 255 255 0
   SYMBOL dash-long
   STATUS ON
  END
  TEMPLATE ind_query.html
 END

END
-----------------------

And Iam calling Query by point as folows

$point = ms_newpointObj();
$point->setXY($lon,$lat);
$layer1 = $map->getLayerByName('Ind');
if($layer1->queryBypoint($point,MS_SINGLE,$buffer) == MS_SUCCESS){
 echo "Success : $buffer";
}

Iam getting this warning message
Warning: [MapServer Error]: msQueryByPoint(): No matching record(s) found.

Iam new to mapserver & I really dont know whether this is the right method to get the info from the dbf file. Iam having only one polygon layer. Do i need to have another layer for quering.?.
Please tell me where Iam going wrong.

The concepts of layers are also not much clear to me. Regarding Mapscript and Map File , reference documents are there but I could not find any elaborate examples or application notes.
 Please tell me where i can find them.

I also could not find any good samples similar to my requirement.

Some one please help me.

Regards
vdharan





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