Dear list, I was wondering if there are any criteria for choosing between GeoJSON or WKT when feeding GeoExt from the database? I care about both transmission size (since many users will have low bandwidth) and processing (users may have low spec hardware, and even the latest Chrome and Opera struggle with too large geometries).
WKT looks more compact, in that there are much fewer square brackets. But since browsers speak javascript, it may be heavier to process? I've written some PHP to generate GeoJSON, like this: http://109.74.202.200/ke/geojson.php, which feeds into http://109.74.202.200/ke/feature-grid.html in the following way: protocol: new OpenLayers.Protocol.HTTP({ url: "geojson.php", format: new OpenLayers.Format.GeoJSON() }) However, looking at http://waterandhealth.eu/, I notice that WKT is used rather than GeoJSON: http://waterandhealth.eu/php/geometries.php Here is a snippet from the javascript: Atlas.data.store.GeometryStore = Ext.extend(Ext.data.JsonStore, { features: [], countryRoot: null, constructor: function (a) { Ext.apply(this, a); Atlas.data.store.GeometryStore.superclass.constructor.call(this, Ext.apply({ proxy: new Ext.data.HttpProxy({ url: "php/geometries.php", method: "POST" }), root: "geometries", fields: ["fid", "geom", "country_id", "country_name"] }, a)); this.addEvents("featureLoad"); this.on("load", function () { this.data.each(function (e, b, f) { var d = OpenLayers.Geometry.fromWKT(e.get("geom")); var c = new OpenLayers.Feature.Vector(d, { id: e.get("fid"), countryId: e.get("country_id"), countryName: e.get("country_name"), value: -1 }); this.features.push(c) }, this); this.fireEvent("featureLoad") }) }, getFeatures: function () { var c = this.features; var d = []; for (var b = 0; b < c.length; b++) { var a = c[b].clone(); d.push(a) } return d } }); Grateful for any guidance. Cheers, Knut _______________________________________________ Users mailing list [email protected] http://www.geoext.org/cgi-bin/mailman/listinfo/users
