[GIS] Openlayers Add features performance for 3000 lines

openlayers-2polyline-creationvector

We would like to implement the function of Addfeature in openlayers to draw lines and push them onto a vector layer, and overlay this layer onto open street map or google map. Those lines are draw dynamically based on the query results from the database.
The only concern so far is the performance issue since we are anticipating about 3000 lines per operation. Has anyone worked on this kind of project before? Do you think it is too heavy on the client side?

Thanks!

Best Answer

Definitely heavy on the client side. On average, how many vertices per features? You will definitely tax older browsers.

A little while back I put together a simple app for an arbitrary number of points in an OpenLayers app as a response to a previous question. Might be helpful for you to gauge performance with large number of graphics.

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[GIS] GeoWebCache and OpenLayers horizontal resolution error

I guess that statkart.no GWC does not support EPSG:4326 projection

Try this:

<script type="text/javascript">
var map, base;

function init(){

    map = new OpenLayers.Map("map", {projection: new OpenLayers.Projection('EPSG:900913')});

    base = new OpenLayers.Layer.WMS(
        "topo2 SK",
        "http://opencache.statkart.no/gatekeeper/gk/gk.open?",
        {layers: "topo2"},
        {attribution:'Map: &copy;<a href="http://www.statkart.no/">Statens kartverk</a>'}
    );
    map.addLayer(base);
    map.zoomToMaxExtent();
}

window.onload = init;
</script>

[GIS] Forcing browser to cache map tiles and re-use them in OpenLayers

I was indeed correct with my hypothesis.

The correct way to set up Apache so that our requests are never duplicated unless required is to set a Expires mod in the HTTPD.conf file.

First, enable the module:

LoadModule expires_module modules/mod_expires.so

Then, turn on caching for PNG images:

ExpiresActive on
ExpiresByType image/png "access plus 1 year"

Since my TileCache is generated once using a pre-seeding script and I don't expect to have to regenerate the images any time in the near future, I can safely set my Expires time to 1 year. Alternatives are 1 day, 1 month, and so on. Note that a hard refresh will dump the client cache and tiles will be requested as usual from the server.

Best Answer

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[GIS] GeoWebCache and OpenLayers horizontal resolution error

[GIS] Forcing browser to cache map tiles and re-use them in OpenLayers

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