topic Re: map.setExtent where extent is common exten of array of features in ArcGIS JavaScript Maps SDK Questions

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

MatejSkerjanc — Thu, 26 Jul 2012 11:34:35 GMT

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?

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

AlanRussian — Thu, 26 Jul 2012 13:14:19 GMT

Hello, Matej,

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

--Alan

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

KenMorefield — Fri, 10 Dec 2021 23:29:51 GMT

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

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

AlanRussian — Fri, 10 Dec 2021 23:29:54 GMT

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?

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

KenMorefield — Thu, 26 Jul 2012 20:11:07 GMT

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

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

AlanRussian — Fri, 10 Dec 2021 23:29:56 GMT

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)

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

KenMorefield — Thu, 26 Jul 2012 22:02:15 GMT

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

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

MatejSkerjanc — Fri, 27 Jul 2012 04:10:56 GMT

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);

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

DouglasHall — Fri, 12 Oct 2012 21:45:27 GMT

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

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

MatejSkerjanc — Mon, 15 Oct 2012 07:50:26 GMT

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

You are most welcome, glad it helped someone.