[OpenLayers-Dev] OpenLayers.Format.KML.write()
Damien Corpataux
damien.corpataux at camptocamp.com
Tue Sep 4 10:28:52 EDT 2007
Hi Tim,
I just posted a patch on ticket #927. The patch suits the requirements:
- KML extends XML
- XML class methods are used for XML manipulation
- tested on FF2/Linux and IE7
- KML.write() returns a string (using XML.write())
- GGE import of OL exported KML is working, and vice-versa
My 2 cents
Cheers,
Damien
Tim Schaub wrote:
> I've opened ticket #927 to track this.
>
> If anybody has a patch for KML, please attach it to that ticket.
> Damien, I've referenced your email on the ticket.
>
> Since XML flavors should now all inherit from the XML format class, I'd
> say that write will always return a string.
>
> Thanks for any contributions.
> Tim
>
>
> Damien Corpataux wrote:
>
>> 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]
>>
>> --
>> Camptocamp SA
>> Damien Corpataux
>> PSE A
>> CH-1015 Lausanne
>> +41 21 619 10 22 (Direct)
>> +41 21 619 10 10 (Centrale)
>> +41 21 619 10 00 (Fax)
>> P Please consider the environment
>> Do you really need to print this email?
>> !DSPAM:4033,46cd662e41812090977483!
>>
>>
>> ------------------------------------------------------------------------
>>
>> _______________________________________________
>> Dev mailing list
>> Dev at openlayers.org
>> http://openlayers.org/mailman/listinfo/dev
>>
>>
>> !DSPAM:4033,46cd662e41812090977483!
>>
>
> _______________________________________________
> Dev mailing list
> Dev at openlayers.org
> http://openlayers.org/mailman/listinfo/dev
>
--
Camptocamp SA
Damien Corpataux
PSE A
CH-1015 Lausanne
+41 21 619 10 22 (Direct)
+41 21 619 10 10 (Centrale)
+41 21 619 10 00 (Fax)
P Please consider the environment
Do you really need to print this email?
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.osgeo.org/pipermail/openlayers-dev/attachments/20070904/e2418c7e/attachment.html
More information about the Dev
mailing list