OpenLayers: Get resolution of map in a given projection (4326)

Posted by David Pfeffer on Stack Overflow See other posts from Stack Overflow or by David Pfeffer
Published on 2010-03-09T05:18:08Z Indexed on 2010/03/09 6:21 UTC
Read the original article Hit count: 247

Filed under:

openlayers

|

JavaScript

|

maps

I'm using OpenLayers to display OpenStreetMap maps. (Though, I'd assume this should be general enough to work for any map product...)

I'm displaying some very sophisticated vector overlays, and the amount and resolution of the features I'm returning from the server via GeoJSON to overlay has proven too much for many computers.

What I'd like to do now instead is to only send data befitting the resolution of the current zoom. This should be relatively easy to do using the getResolution and calculateBounds methods on the Map object. calculateBounds returns a Bounds object that then can be transformed between the map projection and display projection.

How do I transform the resolution into my desired projection (4326 in this case)?

© Stack Overflow or respective owner

Related posts about openlayers

open layers LineString not working

as seen on Stack Overflow - Search for 'Stack Overflow'
Sorry to bother you guys, but I'm stuck with his problem for half a day. I want to draw poly line in OpenLayers using LineString object, so I've copied the example from documentation. It runs ok but i can't see the line on the screen Code looks like this <!DOCTYPE HTML PUBLIC "-//W3C//DTD… >>> More
Trouble with OpenLayers Styles.

as seen on Stack Overflow - Search for 'Stack Overflow'
So, tired of always seeing the bright orange default regular polygons, I'm trying to learn to style OpenLayers. I've had some success with: var layer_style = OpenLayers.Util.extend({},OpenLayers.Feature.Vector.style['default']); layer_style.fillColor = "#000000"; layer_style.strokeColor… >>> More
display MultiPolygonField data on Geodjango/OpenLayers

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi all, I'm a Geodjango novice and would like to get some help on the following: I have a MultiPolygonField field, for a GeoDjango application, and would like to display it on my view as cool as it gets displayed on django admin Say for example I have def index(request): "Index,main view" … >>> More
Customize OpenLayers Control

as seen on Stack Overflow - Search for 'Stack Overflow'
How can I easily customize OpenLayers map controls? Or at least, how can I minimize the controls' height? Thank you. PS. Is there any CSS override? >>> More
OpenLayers: Raise event when map is zoomed or moved by user

as seen on Stack Overflow - Search for 'Stack Overflow'
I'm using OpenLayers to display OpenStreetMap maps. (Though, I'd assume this should be general enough to work for any map product...) I'm displaying some very sophisticated vector overlays, and the amount and resolution of the features I'm returning from the server via GeoJSON to overlay has proven… >>> More

Related posts about JavaScript

CHAT ROOMs 7 by 6

as seen on Stack Overflow - Search for 'Stack Overflow'
I am looking for chatroom on one page with 7 loggedin users and 6+rows for say 42 users.these users will keep on adding wthnew users.Need urgent help.A PRETTY UNUSUAL Q FOR MOST OF U.What is MORE REQ new features: Usernames are unique to users currently chatting You can see a "currently chatting"… >>> More
Integrating JavaScript Unit Tests with Visual Studio

as seen on Stephen Walter - Search for 'Stephen Walter'
Modern ASP.NET web applications take full advantage of client-side JavaScript to provide better interactivity and responsiveness. If you are building an ASP.NET application in the right way, you quickly end up with lots and lots of JavaScript code. When writing server code, you should be writing… >>> More
Has Javascript developed beyond what it was originally designed to do?

as seen on Programmers - Search for 'Programmers'
I've been talking with a friend about the purpose of Javascript, when and how it should be used, etc. He quoted that: JavaScript was designed to add interactivity to HTML pages [...] JavaScript gives HTML designers a programming tool HTML authors are normally not programmers… >>> More
PHP, javascript, single quote problems with IE when passing variable from ajax post to javascript fu

as seen on Stack Overflow - Search for 'Stack Overflow'
Hi! I have been trying to get this to work for a while, and I suspect there's an easy solution that I just can't find. My head feels like jelly and I would really appreciate any help. My main page.php makes a .post() to backend.php and fetches a list of cities which it echoes in the form of: <li… >>> More
Javascript in XSL that is loaded by Javascript

as seen on Stack Overflow - Search for 'Stack Overflow'
Is there anyway to have javascript run when a XSL sheet has been applied to an XML file by Javascript? I am using a JQuery plugin to apply the sheet to the xml but the javascript that is located inside of the XSL file will not run. I put the Javascript at the bottom of the file and it still does… >>> More