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map.setExtent where extent is common exten of array of features

MatejSkerjanc

i get array of features via a function (like query) and i create common extent from the array and then i use map.setExtent(arrayExtent, true);

The problem is the map doesnt create extent where all features would be visible in other words it sets too small extent.
Has anyone else seen this peculiar behavior?

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AlanRussian

Hello, Matej,

Could you please post the code that creates the common extent from the array?

--Alan

KenMorefield

Hi Alan,
Here is a function I wrote which will apply a definition query on a featureLayer based upon the selected value in a combo box. I then select features within the featureLayer based on the definition query, and then union the extent of each selected feature.

function selectAnimal(item) {
    //apply a definition expression to the layer to only display trees of the selected species 
    var query = "Animal_ID LIKE'${name}'"; 
    homerangeLayer.setDefinitionExpression(esri.substitute({ 
        name: dojo.trim(item.value) 
    }, query));
 homerangeLayer.selectFeatures(query, esri.layers.FeatureLayer.SELECTION_NEW, function(results) {
  var unionExtent;
  for (var i = 0, il = results.length; i < il; i++) {
            if (unionExtent) {
                //if extent already initialized, union it with new feature extent
                unionExtent = unionExtent.union(new esri.geometry.Extent(results.geometry.getExtent()));
            }
            else {
                //if extent not initialized, set it to feature's extent
                unionExtent = new esri.geometry.Extent(new esri.geometry.Extent(results.geometry.getExtent()));
            }
   console.log(unionExtent);
        }
        //zoom to the extent of all polygons.
        map.setExtent(unionExtent.expand(1.5));
 });
}

Hopefully this code makes sense to you!

Ken

AlanRussian

function selectAnimal(item) {
    //apply a definition expression to the layer to only display trees of the selected species 
    var query = "Animal_ID LIKE'${name}'"; 
    homerangeLayer.setDefinitionExpression(esri.substitute({ 
        name: dojo.trim(item.value) 
    }, query));
    homerangeLayer.selectFeatures(query, esri.layers.FeatureLayer.SELECTION_NEW, function(results) {
        var unionExtent;
        for (var i = 0, il = results.length; i < il; i++) {
            if (unionExtent) {
                //if extent already initialized, union it with new feature extent
                unionExtent = unionExtent.union(new esri.geometry.Extent(results.geometry.getExtent()));
            }
            else {
                //if extent not initialized, set it to feature's extent
                unionExtent = new esri.geometry.Extent(new esri.geometry.Extent(results.geometry.getExtent()));
            }
            console.log(unionExtent);
        }
        //zoom to the extent of all polygons.
        map.setExtent(unionExtent.expand(1.5));
    });
}

Hopefully this code makes sense to you!

Ken

And you said you've tried map.setExtent(unionExtent.expand(1.5), true);, correct?

Screenshot 2025-04-28 025833.png

KenMorefield

I use -

map.setExtent(unionExtent.expand(1.5));

I don't use -

map.setExtent(unionExtent.expand(1.5), true);

The top one works perfectly for me...
And just to clarify, I'm using it with version 2.8 of the API.

Ken

AlanRussian

I use -

map.setExtent(unionExtent.expand(1.5));

I don't use -

map.setExtent(unionExtent.expand(1.5), true);

The top one works perfectly for me...
And just to clarify, I'm using it with version 2.8 of the API.

Ken

Could you try the following and see if it works?

map.setExtent(unionExtent.expand(1.5), true);

From the documentation:

When true, for maps that contain tiled map service layers, you are guaranteed to have the input extent shown completely on the map. (As of v1.3)

KenMorefield

That seems to work exactly the same for me. I verified that both ways zoom me to the exact same extent. Is it not working for you?

Ken

MatejSkerjanc

allanrusian here's the code

var xmax, xmin, ymin, ymax;
var extent;

if(features[0].geometry.type != "point")
{
//initial extent
extent = features[0].geometry.getExtent();
xmax = extent.xmax;
xmin = extent.xmin;
ymax = extent.ymax;
ymin = extent.ymin;

dojo.forEach(features, function(feature)
{
   extent = feature.geometry.getExtent();
   //alert(extent.xmin + ',' + extent.ymin + ',' + extent.xmax + ',' + extent.ymax);
   if(extent.xmax > xmax)
    xmax = extent.xmax;
   if(extent.xmin < xmin)
    xmin = extent.xmin;
   if(extent.ymax > ymax)
    ymax = extent.ymax;
   if(extent.xmin < ymin)
    ymin = extent.ymin;
});
}
else
{
//initial extent za pike

   xmin = features[0].geometry.x;
   ymin = features[0].geometry.y;
   xmax = features[0].geometry.x;
   ymax = features[0].geometry.y;

dojo.forEach(features, function(feature)
{
   if(feature.geometry.x > xmax)
    xmax = feature.geometry.x;
   if(feature.geometry.y > ymax)
    ymax = feature.geometry.y;

   if(feature.geometry.x < xmin)
    xmin = feature.geometry.x;
   if(feature.geometry.y < ymin)
    ymin = feature.geometry.y;
});

}

//var xtent =new esri.geometry.Extent(xmin-factor, ymin-factor, xmax+factor, ymax+factor, map.spatialReference)
var xtent = new esri.geometry.Extent({
"xmin":xmin,
"ymin":ymin,
"xmax":xmax,
"ymax":ymax, "spatialReference": { "wkid":map.spatialReference.wkid }
});

map.setExtent(xtent, true);

DouglasHall

Thanks Detroit -- needed the section that creates an extent for a set of points!

MatejSkerjanc

Thanks Detroit -- needed the section that creates an extent for a set of points!

You are most welcome, glad it helped someone.

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