[OpenLayers-Users] Measure control problem

[Steve.Toutant at inspq.qc.ca]

No, I need planar distance since my map is in Mercator projection.
I provided The coordinates of point 1 and point 2 in lat/long just for 
test purpose.

Sorry for the confusion.
Steve

Steve Toutant, M. Sc.
Analyste en géomatique
Secteur environnement
Direction des risques biologiques, environnementaux et occupationnels
Institut national de santé publique du Québec
945, avenue Wolfe
Québec, Qc G1V 5B3 
Tél.: (418) 650-5115 #5281
Fax.: (418) 654-3144
steve.toutant at inspq.qc.ca
http://www.inspq.qc.ca
 




Kwong Hu Kiu <kwonghu at hotmail.com> 
03/08/2009 10:47 AM

A
<steve.toutant at inspq.qc.ca>, <users at openlayers.org>
cc

Objet
RE: [OpenLayers-Users] Measure control problem









I think you are looking for the Vincenty distance formula.
It's included in the examples as well.

To: users at openlayers.org
From: Steve.Toutant at inspq.qc.ca
Date: Mon, 3 Aug 2009 10:44:10 -0400
Subject: [OpenLayers-Users] Measure control problem


Hello, 
I created a measure control based on the measure.js example 
My measure control doesn't display the good distance. The distance is 
longer than expected. 
I tried with these coordinates 
# : lat, long 
Point 1 : 46.81509864093307, -71.22436522446064 
Point 2 :  45.54483148742626, -73.63037108350094 
The control gives 336.824 km 
It should be around 233 km 

Do you have an idea on what could be the cause of this error? 

Here is my code 
//the mapOptions of OL are 
projection: "EPSG:900913", 
displayProjection: new OpenLayers.Projection("EPSG:4326"), //Pour afficher 
les coord lat long 
units: "m", 

var mesureControl = new OpenLayers.Control.Measure( 
                           OpenLayers.Handler.Path, 
                                        { 
                               persist: true, 
                geodesic: false, 
                               handlerOptions: 
                                                { 
                        //           layerOptions: {styleMap: styleMap} 
                               } 
                           } 
                               ); 
mesureControl.events.on 
({ 
    "measure": handleMeasurements, 
        "measurepartial": handleMeasurements 
}); 
map.addControl(mesureControl); 
 
function handleMeasurements(event) 
{ 
        var geometry = event.geometry; 
        var units = event.units; 
        var measure = event.measure; 
 
        alert( measure.toFixed(3) + " " + units, "" ); 
} 

//geoExt toolbar 
action = new GeoExt.Action({ 
        control: mesureControl, 
    map: map, 
    toggleGroup: "map", 
        iconCls: 'measure', 
        tooltip: 'Mesure linéaire' 
    }); 
    toolbar.push(action);                 

Thanks for your help, 
Steve 

Steve Toutant, M. Sc.
Analyste en géomatique
Secteur environnement
Direction des risques biologiques, environnementaux et occupationnels
Institut national de santé publique du Québec
945, avenue Wolfe
Québec, Qc G1V 5B3 Tél.: (418) 650-5115 #5281
Fax.: (418) 654-3144
steve.toutant at inspq.qc.ca
http://www.inspq.qc.ca 
  



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