topic Zoom in Zoom out control in ArcGIS JavaScript Maps SDK Questions

Zoom in Zoom out control

PramodHarithsa1 — Fri, 08 Jun 2012 05:26:36 GMT

Hi,
I have two external button for zoomin and zoom out.
on click of zoomin button i am using

map.centerAndZoom()

function.
But it doesnt work for me.
i want the extent to be maximixed and minimized..

when use this,
map.centerAndZoom((0,0),1)
map.centerAndZoom((0,0),2)

map centers to one position.. how do i make it dynamic..
i.e., on click on button it should keep zooming in.. and similarly the zoom out button as well

what other functions for the same can i manifest?

Re: Zoom in Zoom out control

derekswingley1 — Fri, 08 Jun 2012 15:24:13 GMT

If you're using a tiled service, you can get the map's level, add or subtract one from it depending on which button is clicked and pass that as the second argument to centerAndZoom.

If you're not using a tiled service, centerAndZoom probably isn't what you want. Rather, try building a new extent and using map.setExtent. More info about using extents: http://help.arcgis.com/en/webapi/javascript/arcgis/help/jshelp/intro_extents.htm

Re: Zoom in Zoom out control

PramodHarithsa1 — Mon, 11 Jun 2012 04:26:24 GMT

If you're using a tiled service, you can get the map's level, add or subtract one from it depending on which button is clicked and pass that as the second argument to centerAndZoom.

If you're not using a tiled service, centerAndZoom probably isn't what you want. Rather, try building a new extent and using map.setExtent. More info about using extents: http://help.arcgis.com/en/webapi/javascript/arcgis/help/jshelp/intro_extents.htm

I have a tiled service layer as well as a DynamicMapServiceLayer in the map..
for the location attribute i tried something like (map.extent.xmin+map.extent.xmax)/2 and similarly for y parameter.. but it didn't work for me.
I just want the + and - functionality of zoom slider into buttons i have defined!

Re: Zoom in Zoom out control

PramodHarithsa1 — Mon, 11 Jun 2012 10:24:46 GMT

With Reference to the doc.,
http://help.arcgis.com/en/webapi/javascript/arcgis/help/jsapi_start.htm

How are the constants ZOOM_IN and ZOOM_OUT used?

Re: Zoom in Zoom out control

HemingZhu — Mon, 11 Jun 2012 13:58:37 GMT

Hi,
I have two external button for zoomin and zoom out.
on click of zoomin button i am using
map.centerAndZoom()
function.
But it doesnt work for me.
i want the extent to be maximixed and minimized..

when use this,
map.centerAndZoom((0,0),1)
map.centerAndZoom((0,0),2)

map centers to one position.. how do i make it dynamic..
i.e., on click on button it should keep zooming in.. and similarly the zoom out button as well

what other functions for the same can i manifest?

Try this:
For ZoomIn Button:
var extent=map.extent;
map.setExtent(extent.expand(0.5));
For ZoomOut Button:
var extent=map.extent;
map.setExtent(extent.expand(2));

Re: Zoom in Zoom out control

PramodHarithsa1 — Tue, 12 Jun 2012 04:29:12 GMT

Try this:
For ZoomIn Button:
var extent=map.extent;
map.setExtent(extent.expand(0.5));
For ZoomOut Button:
var extent=map.extent;
map.setExtent(extent.expand(2));

Thanks a lot Zhu, That worked for me..
where can i get such methods described? I was looking here http://help.arcgis.com/en/webapi/javascript/arcgis/help/jshelp_start.htm

Re: Zoom in Zoom out control

HemingZhu — Tue, 12 Jun 2012 13:05:05 GMT

Thanks a lot Zhu, That worked for me..
where can i get such methods described? I was looking here http://help.arcgis.com/en/webapi/javascript/arcgis/help/jshelp_start.htm

Under API Reference Tab looking for Geometry -> Extent.