MapscriptByPoint query returns no results

I have a dynamically generated map file made with C # mapcript, which is defined as:

MAP EXTENT 5.91828 45.63552 5.92346 45.65051 IMAGECOLOR 192 192 192 IMAGETYPE png SIZE 256 256 STATUS ON TRANSPARENT TRUE UNITS METERS NAME "GMAP_TILE" OUTPUTFORMAT NAME "png" MIMETYPE "image/png" DRIVER "GD/PNG" EXTENSION "png" IMAGEMODE "PC256" TRANSPARENT TRUE END SYMBOL NAME "circle" TYPE ELLIPSE FILLED TRUE POINTS 1 1 END END SYMBOL NAME ">" TYPE TRUETYPE ANTIALIAS TRUE CHARACTER ">" GAP -20 FONT "arial" POSITION CC END PROJECTION "proj=merc" "a=6378137" "b=6378137" "lat_ts=0.0" "lon_0=0.0" "x_0=0.0" "y_0=0" "units=m" "k=1.0" " nadgrids=@null " END LEGEND IMAGECOLOR 255 255 255 KEYSIZE 20 10 KEYSPACING 5 5 LABEL SIZE MEDIUM TYPE BITMAP BUFFER 0 COLOR 0 0 0 FORCE FALSE MINDISTANCE -1 MINFEATURESIZE -1 OFFSET 0 0 PARTIALS TRUE END POSITION LL STATUS OFF END QUERYMAP COLOR 255 255 0 SIZE -1 -1 STATUS ON STYLE HILITE END SCALEBAR ALIGN CENTER COLOR 0 0 0 IMAGECOLOR 255 255 255 INTERVALS 4 LABEL SIZE MEDIUM TYPE BITMAP BUFFER 0 COLOR 0 0 0 FORCE FALSE MINDISTANCE -1 MINFEATURESIZE -1 OFFSET 0 0 PARTIALS TRUE END POSITION LL SIZE 200 3 STATUS OFF STYLE 0 UNITS MILES END WEB IMAGEPATH "" IMAGEURL "" QUERYFORMAT text/html LEGENDFORMAT text/html BROWSEFORMAT text/html END LAYER NAME "Troncons" PROJECTION "proj=longlat" "ellps=WGS84" "datum=WGS84" END STATUS DEFAULT TEMPLATE "nofile.html" TOLERANCE 100 TOLERANCEUNITS METERS TYPE LINE UNITS METERS CLASS NAME "Troncons" STYLE ANGLE 360 COLOR 0 0 255 SIZE 5 SYMBOL "circle" WIDTH 5 END STYLE ANGLE 360 COLOR 0 0 0 SIZE 12 SYMBOL ">" WIDTH 1 END END FEATURE POINTS 5.91828 45.63552 5.91876 45.63611 5.91898 45.6364 5.91936 45.63701 5.91952 45.63731 5.91968 45.63762 5.91993 45.63825 5.92003 45.63856 5.92018 45.63919 5.92028 45.63983 5.92031 45.64014 5.92033 45.64046 5.92034 45.64077 5.92034 45.64108 5.92034 45.64171 5.92035 45.64234 5.92035 45.6428 5.92037 45.6433 5.9204 45.64394 5.92046 45.64458 5.92056 45.64522 5.92062 45.64554 5.92069 45.64586 5.92077 45.64617 5.92097 45.64679 5.92122 45.64739 5.92136 45.64769 5.92169 45.64828 5.92207 45.64886 5.92228 45.64914 5.92272 45.64969 5.92321 45.65023 5.92346 45.65051 END END END END 

I am trying to execute a ByPoint query to get a closed figure index. In the code below, I made a specific test function with a fixed point instead of the points passed by the parameter, so I'm sure that the point I use is actually part of the function. In my case, I use the first point of the only function contained in the map file.

 public string GetTronconId() { //_map is my dynamically created mapObj if (_map != null) for (int i = 0; i < _map.numlayers; i++) { layerObj layer = _map.getLayer(i); // Code never pass this point if (layer.queryByPoint(_map, new pointObj(5.91898, 45.6364, 0, 0), (int) MS_QUERY_MODE.MS_QUERY_MULTIPLE, 100) == (int) MS_RETURN_VALUE.MS_SUCCESS) { int numresults = layer.getNumResults(); if (numresults != 0) { layer.open(); for (int j = 0; j < numresults; j++) { resultCacheMemberObj resultat = layer.getResult(j); shapeObj shape = null; if (layer.getShape(shape, resultat.tileindex, resultat.shapeindex) == (int) MS_RETURN_VALUE.MS_SUCCESS) return shape.getValue(0); } } } } return null; } 

I have a dummy set of TEMPLATE, I don’t know, I need to use tolerance because the point has a sharp shape in the form, but queryByPoint continues to return MS_FAILURE to me. From my searches on the web, everything seems OK. Any idea?

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3 answers

Well, the second attempt: the querybypoint function needs the query point in the map projection, not the layer projection.

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Your layer has a lonlat projection, but UNITS METERS. Remove this from the layer or change it to DD.

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I think you should open the layer before you can get functions from it:

open (): void Opens the bottom layer. This is necessary before getFeature () will work, but is not required before calling a draw or calling.

http://mapserver.org/mapscript/mapscript.html#layerobj

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Source: https://habr.com/ru/post/1300735/


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