[OpenLayers-Dev] OpenLayers.Format.KML.write()
Damien Corpataux
damien.corpataux at camptocamp.com
Thu Aug 23 06:48:49 EDT 2007
Hello,
As far as I can see, the advantages of doing so are obvious. Althought I
didn't have time to apply these, here is a new version of the patch:
- puts placemarks in a folder tag (for google earth import)
- bugfix with geometry tags
Is the question about write() return type (string or DOMDocuemt/DOMNode)
still open?
Cheers,
Damien
Patch:
Index: /home/dcorpataux/workspace/openlayers/lib/OpenLayers/Format/KML.js
===================================================================
---
/home/dcorpataux/workspace/openlayers/lib/OpenLayers/Format/KML.js
(revision 3900)
+++
/home/dcorpataux/workspace/openlayers/lib/OpenLayers/Format/KML.js
(working copy)
@@ -8,8 +8,8 @@
* @requires OpenLayers/Ajax.js
*
* Class: OpenLayers.Format.KML
- * Read only KML. Largely Proof of Concept: does not support advanced
Features,
- * including Polygons. Create a new instance with the
+ * Read/write KML 2.0. Does not support advanced Features.
+ * Create a new instance with the
* <OpenLayers.Format.KML> constructor.
*
* Inherits from:
@@ -24,6 +24,24 @@
kmlns: "http://earth.google.com/kml/2.0",
/**
+ * APIProperty: placemarksDesc
+ * Default description for a placemark
+ */
+ placemarksDesc: "No description available",
+
+ /**
+ * APIProperty: foldersName
+ * Default name for a folder
+ */
+ foldersName: "OpenLayers export",
+
+ /**
+ * APIProperty: foldersDesc
+ * Default description for a folder
+ */
+ foldersDesc: "Exported on " + new Date(),
+
+ /**
* Constructor: OpenLayers.Format.KML
* Create a new parser for KML
*
@@ -46,7 +64,7 @@
if (typeof data == "string") {
data = OpenLayers.parseXMLString(data);
}
- var featureNodes = OpenLayers.Ajax.getElementsByTagNameNS(data,
this.kmlns, "", "Placemark");
+ var featureNodes = OpenLayers.Ajax.getElementsByTagNameNS(data,
this.kmlns, "kml", "Placemark");
var features = [];
@@ -100,6 +118,19 @@
// TBD Bounds only set for one of multiple geometries
geom.extendBounds(p.bounds);
}
+
+ // match Polygon
+ } else if (OpenLayers.Ajax.getElementsByTagNameNS(xmlNode,
+ this.kmlns, "", "Polygon").length != 0) {
+ var polygon = OpenLayers.Ajax.getElementsByTagNameNS(xmlNode,
+ this.kmlns, "", "Polygon")[0];
+ p = this.parseCoords(polygon);
+ if (p.points) {
+ var linearRing = new
OpenLayers.Geometry.LinearRing(p.points);
+ geom = new OpenLayers.Geometry.Polygon(linearRing);
+ // TBD Bounds only set for one of multiple geometries
+ geom.extendBounds(p.bounds);
+ }
}
feature.geometry = geom;
@@ -191,5 +222,171 @@
return p;
},
+ /**
+ * Method: write
+ * Accept Feature Collection, and return an XML Document.
+ *
+ * Parameters:
+ * features - An array of <OpenLayers.Feature.Vector> features.
+ *
+ * Returns:
+ * <DOMDocument>
+ */
+ write: function(features) {
+ var kml = document.createElementNS(this.kmlns, "kml");
+ var folder = this.createFolderXML();
+ for (var i=0; i < features.length; i++) {
+ folder.appendChild(this.createPlacemarkXML(features[i]));
+ }
+ kml.appendChild(folder);
+ return kml;
+ },
+
+ /**
+ * Method: createFolderXML
+ * Creates and returns a KML Folder node with default name and
description
+ *
+ * Returns:
+ * xmlNode - {<XMLNode>}
+ */
+ createFolderXML: function() {
+ // Folder name
+ var folderName = document.createElementNS(this.kmlns, "name");
+ var folderNameText = document.createTextNode(this.foldersName);
+ folderName.appendChild(folderNameText);
+
+ // Folder description
+ var folderDesc = document.createElementNS(this.kmlns,
"description");
+ var folderDescText = document.createTextNode(this.foldersDesc);
+ folderDesc.appendChild(folderDescText);
+
+ // Folder
+ var folder = document.createElementNS(this.kmlns, "Folder");
+ folder.appendChild(folderName);
+ folder.appendChild(folderDesc);
+
+ return folder;
+ },
+
+ /**
+ * Method: createPlacemarkXML
+ * Accept an OpenLayers.Feature.Vector, and create a KML Placemark node
+ *
+ * Parameters:
+ * feature - {<OpenLayers.Feature.Vector>}
+ *
+ * Returns:
+ * xmlNode - {<XMLNode>}
+ */
+ createPlacemarkXML: function(feature) {
+ // Placemark name
+ var placemarkName = document.createElementNS(this.kmlns, "name");
+ var placemarkNameText = document.createTextNode(feature.id);
+ placemarkName.appendChild(placemarkNameText);
+
+ // Placemark description
+ var placemarkDesc = document.createElementNS(this.kmlns,
"description");
+ var placemarkDescText =
document.createTextNode(this.placemarksDesc);
+ placemarkDesc.appendChild(placemarkDescText);
+
+ // Placemark
+ var placemarkNode = document.createElementNS(this.kmlns,
"Placemark");
+ placemarkNode.appendChild(placemarkName);
+ placemarkNode.appendChild(placemarkDesc);
+
+ // Geometry node (Point, LineString, etc. nodes)
+ var geometryNode = this.buildGeometryNode(feature.geometry);
+ placemarkNode.appendChild(geometryNode);
+
+ return placemarkNode;
+ },
+
+ /**
+ * Method: buildGeometryNode
+ * Builds a KML geometry node with a given geometry
+ *
+ * Parameters:
+ * geometry - {<OpenLayers.Geometry>}
+ *
+ * Returns:
+ * xmlNode - {<XMLNode>}
+ */
+ buildGeometryNode: function(geometry) {
+ // TBD test if geoserver can be given a Multi-geometry for a
simple-geometry data store
+ // ie if multipolygon can be sent for a polygon feature type
+ var kml = "";
+ // match MultiPolygon or Polygon
+ if (geometry.CLASS_NAME == "OpenLayers.Geometry.MultiPolygon"
+ || geometry.CLASS_NAME == "OpenLayers.Geometry.Polygon") {
+ kml = document.createElementNS(this.kmlns, 'Polygon');
+
+ var outerRing = document.createElementNS(this.kmlns,
'outerBoundaryIs');
+ var linearRing = document.createElementNS(this.kmlns,
'LinearRing');
+
+ // TBD manage polygons with holes
+
linearRing.appendChild(this.buildCoordinatesNode(geometry.components[0]));
+ outerRing.appendChild(linearRing);
+
+ kml.appendChild(outerRing);
+ }
+ // match MultiLineString or LineString
+ else if (geometry.CLASS_NAME ==
"OpenLayers.Geometry.MultiLineString"
+ || geometry.CLASS_NAME ==
"OpenLayers.Geometry.LineString") {
+ kml = document.createElementNS(this.kmlns,
'LineString');
+
+ kml.appendChild(this.buildCoordinatesNode(geometry));
+ }
+ // match MultiPoint or Point
+ else if (geometry.CLASS_NAME == "OpenLayers.Geometry.Point" ||
+ geometry.CLASS_NAME ==
"OpenLayers.Geometry.MultiPoint") {
+ kml = document.createElementNS(this.kmlns, 'Point');
+
+ // FIXME: There should be only one Point node per
Placemark node
+ var parts = "";
+ if (geometry.CLASS_NAME ==
"OpenLayers.Geometry.MultiPoint") {
+ parts = geometry.components;
+ } else {
+ parts = [geometry];
+ }
+
+ for (var i = 0; i < parts.length; i++) {
+ kml.appendChild(this.buildCoordinatesNode(parts[i]));
+ }
+ }
+ return kml;
+ },
+ /**
+ * Method: buildCoordinatesNode
+ * builds the KML coordinates node
+ *
+ * Parameters:
+ * geometry - {<OpenLayers.Geometry>}
+ *
+ * Returns:
+ * xmlNode - {<XMLNode>}
+ */
+ buildCoordinatesNode: function(geometry) {
+ var coordinatesNode = document.createElementNS(this.kmlns,
"coordinates");
+
+ var points = null;
+ if (geometry.components) {
+ points = geometry.components;
+ }
+
+ var path = "";
+ if (points) {
+ for (var i = 0; i < points.length; i++) {
+ path += points[i].x + "," + points[i].y + " ";
+ }
+ } else {
+ path += geometry.x + "," + geometry.y + " ";
+ }
+
+ var txtNode = document.createTextNode(path);
+ coordinatesNode.appendChild(txtNode);
+
+ return coordinatesNode;
+ },
+
CLASS_NAME: "OpenLayers.Format.KML"
});
Tim Schaub wrote:
> Hi-
>
> So, we're mid-way through changing how XML flavors are read/written in
> OpenLayers.
>
> I've checked a new XML format in to the trunk. This format has most of
> the methods we need for reading/writing XML cross-browser.
>
> To parse other XML flavors, format classes should be created that
> inherit from the XML format.
>
> For an (incomplete) example, see:
> http://dev.openlayers.org/sandbox/tschaub/xml/lib/OpenLayers/Format/GML.js
>
> (The important part to notice in the above example is that the GML
> format inherits from the XML format.)
>
> Instead of using OpenLayers.Ajax methods or document methods, DOM
> creation and traversal should be done with OpenLayers.Format.XML
> methods. I've created methods to reflect the W3C standard XML DOM
> methods - wrapping the standard ones and accommodating for non-compliant
> browsers.
>
> If you (or anyone) needs additional XML DOM methods, they should be
> added to the XML format. The next addition (in my mind) is
> setAttributeNS. Aside from that, you should be able to do efficient
> parsing and dom creation with the XML format methods.
>
> Please make modifications to the KML format in the trunk. Create a
> ticket and attach patches in Trac. I can offer review or other help as
> needed.
>
> I don't have time to keep these sandboxes entirely clean right now - so
> please forgive anything you find that is in a half-developed state.
>
> Tim
>
> PS - Eventually, I'll move the following example into the trunk. It
> would be nice if we could demonstrate read/write capability for all
> vector formats in this way:
> http://dev.openlayers.org/sandbox/tschaub/xml/examples/vector-formats.html
>
> (note again that this reflects partially complete work - and you should
> not be surprised to encounter errors or see changes at any time)
>
>
> Damien Corpataux wrote:
>
>> Hello,
>>
>> Here's what I did so far... Reading KML only work for KML 2.0 namespaces
>> for write() uses OpenLayers.Ajax.getElementsByTagNameNS(), but I'm
>> pretty sure it will work on future versions (2.1 parsing successful).
>> Also, GML and KML write() returns a Dom Document rather than a string.
>> Should one change the result type, breaking OpenLayers.Format interface,
>> or parse it into a string using OpenLayers.XML.....?
>>
>> Cheers,
>> Damien
>>
>>
[patch stripped]
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Damien Corpataux
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