'kml item' hook needs more flexibility
| Project: | KML module |
| Version: | 5.x-1.x-dev |
| Component: | Code |
| Category: | feature request |
| Priority: | normal |
| Assigned: | Unassigned |
| Status: | closed |
Hi,
I have recently produced the trackfield.module (http://drupal.org/project/trackfield). As part of this have managed to utilise the 'kml item' hook to place paths in KML output. There is a problem with how things currently work though:
Whatever data you return is added inside the existing <Placemark> element. For example, the trackfield module can return (co-ord list mostly removed for space):
Array
(
[Linestring] => Array
(
[key] => LineString
[value] => <coordinates>151.234721,-33.768547,0 151.23741,-33.763535,0</coordinates>
)
)Which makes KML output for this <Placemark>:
<Placemark>
<name>...snip...</name>
<description>...snip...</description>
<styleUrl>#NodeStyleMap</styleUrl>
<TimeStamp><when>2008-03-14T10:01:13Z</when></TimeStamp>
<Point>
<altitudeMode>relativeToGround</altitudeMode>
<coordinates>151.236505,-33.765448,0</coordinates>
</Point>
<LineString><coordinates>151.234721,-33.768547,0 151.23741,-33.763535,0</coordinates></LineString>
</Placemark>This confuses Google Earth and it seems to be able to treat a <Placemark> as a point or a line, but not both. Luckily for us the <LineString> seems to take precedent over <Point> and the track is displayed, but that's not what is really required. To show both is needed so the line has a label hovering above it.
What seems to be needed is a way to have the hook be able to return something that creates another <Placemark> element inside the KML output, something like:
<Placemark>
<name>...snip...</name>
<description>...snip...</description>
<styleUrl>#NodeStyleMap</styleUrl>
<TimeStamp><when>2008-03-14T10:01:13Z</when></TimeStamp>
<Point>
<altitudeMode>relativeToGround</altitudeMode>
<coordinates>151.236505,-33.765448,0</coordinates>
</Point>
</Placemark>
<Placemark>
<name>...snip...</name>
<description>...snip...</description>
<styleUrl>#NodeStyleMap</styleUrl>
<TimeStamp><when>2008-03-14T10:01:13Z</when></TimeStamp>
<LineString><coordinates>151.234721,-33.768547,0 151.23741,-33.763535,0</coordinates></LineString>
</Placemark>How do you think this would be best achieved?
Maybe if the key in the returned array is <Placemark> then the value could be added as such after the existing one?
#1
Playing more with this I have discovered the
MultiGeometrytag as discussed here:http://code.google.com/apis/kml/documentation/kmlreference.html#multigeo...
It would seem that this is probably the way to go. One can use this tag to overcome the 'confusion' I first mention and allow both
PointandLineStringelements to be handled properly inside the same placemark.I would propose a small patch to the KML module that looked through the args array in
kml_format_placemarkfunction and any elements that were themself geometry tags would be placed with the default placemark inside aMultiGeometrytag.This should be easy enough to do and will work on it shortly.
#2
As per #1 please find patch attached.
This handles all geometry types and the MultiGeometry tag itself inside the
$extrareturned from$extra = node_invoke_nodeapi($item, 'kml item');.For efficient styling it might be nice to add a prior hook call for other modules to add their style information. This can be embedded at the moment but is on a per-node basis rather than using style IDs.
#3
Now committed to cvs:
http://drupal.org/cvs?commit=130675
#4
Automatically closed -- issue fixed for two weeks with no activity.