I have an app that over time writes Placemarks to a kml file, slowly building up a route over time.
When I open the file in Google Earth, I can see the Placemarks already in the file, but any new ones added to the doc aren't shown on the map, until I reopen the document again.
Is there any way of getting the document to auto refresh in Google earth?
I've tried putting a NetworkLink into the document whose href points itself (the file) with a refreshMode of onChange, and that works, but the whole document is reloaded on each change and each point is displayed again, which is messy.
NOTE: I can't change the apps code, to generate single Placemark updates, which I believe is the proper way of using NetworkLinks.
The only way to perform incremental updates in KML is using the NetworkLinkControl element in conjunction with a NetworkLink.
NetworkLinkControl controls the behavior of files fetched by a <NetworkLink> in which you can change, add, or delete elements that you already fetched.
<NetworkLinkControl>
<cookie>cookie=sometext</cookie>
<linkName>link name</linkName>
<Update>
<targetHref>same-targethref-for-networklink</targetHref>
<Create>
<Document targetId="targetdoc">
<Placemark>
<name>Created place1</name>
</Placemark>
<Placemark>
<name>Created place2</name>
</Placemark>
</Document>
</Create>
...
</Update>
</NetworkLinkControl>
The NetworkLinkControl is tricky to get working such as the URLs in the NetworkLink and NetworkLinkControl must match exactly.
You can find a tutorial with an example to get started.
https://developers.google.com/kml/documentation/updates
So I guess you can't. I thought there might be some kind of structure within kml to achieve this, nut it would appear not.
Related
I have a KML file with a few different placemarks all around the globe. I would like to flyto the first placemark and display it's balloon, wait a minute or two, then flyto the next placemark, and repeat this process until all of the placemarks have been shown.
I think I might be able to achieve this by putting all the placemarks into a tour but this doesn't seem like the right approach. I'm going to be refreshing the KML from a server and I'm not sure how a tour would react to that (e.g., I think you have to always click play before starting a tour).
If this isn't possible I may have to place just a single placemark in the KML file and then keep refreshing the file with a different placemark. I think that approach might be bad though because it will be refreshing a lot more.
I ended up putting one placemark per KML file. I wrote a program in Java that uses the Saxon processor and an XSLT stylesheet to create multiple KML files with just a single placemark per file then using this tutorial I was able to cycle through the KML files one-by-one.
When doing this locally on my machine I created two folders. Folder A housed all the KML files. Folder B would house only one KML file which would be the file expected from the KML NetworkLink tag. In the Java program I had a timer thread that sequentially deletes the single file in Folder B, cuts a file out of Folder A, moves it into Folder B, then renames the newly placed file the common name which the KML NetworkLink tag expects. I hope this helps and the link will help this to make more sense.
(Base KML file which is loaded into Google Earth - Basically tells Google Earth to look for the file called every10.kml every 10 seconds. If we swap that file out, say, every 9 seconds, then once it's refreshed by Google Earth it will be a new KML file thus showing the new placemark)
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://earth.google.com/kml/2.1">
<Document>
<NetworkLink>
<Link>
<href>every10.kml</href>
<refreshMode>onInterval</refreshMode>
<refreshInterval>10</refreshInterval>
</Link>
</NetworkLink>
</Document>
</kml>
KML newb here. First post.
Using GE client application, v7.12. Have fairly simple KML doc containing placemarks to several GPS time-based breadcrumb points. Wrote a simple C# app to generate the kml doc. Expect to have several more like files for additional tracked entities. I get this working and decide to fancy up the placemark balloons via HTML. Ultimately decide I'd like to have links in the balloon to move to the previous or next placemark. Find advice on this site and make it happen.
Since my app may update(by rewriting) the doc at times it would be nice to not have to manually reload it. Plus there will ultimately be other docs for other tracked entities, all controlled/updated by my app. OK - NetworkLink to the rescue. Cool feature and gives me the option of dynamically modifying the networklinks file to only include the entity doc files that have changed. Plus big bonus -- turning 'flyToView' off so that when networklinks file is reloaded or refresh fires, I'm not pulled away from whatever I'm currently viewing by the default 'LookAt' that normally seems to happen when a doc is loaded directly (anyone know a way around this?)
Very happy, until I discover that when I click one of my balloon links to move to the next or previous point, GE decides to create a new copy of the entire containing document under Temporary Places and now I have two entire sets of points displayed, one hiding the other. On the surface, my next/prev links appear to be working, but they are actually only working with the newly created doc. To test, I alter the original doc with an entirely different set of locations. Reload the networklinks doc to bring in the new point-laden doc and see the new set of points. But when I use any balloon links on the new, they jump to points on the older doc that GE had created on its own. Delete the GE-created version, click balloon and viola, GE creates a new copy of it and were back where we started. Frustrating.
As placemark IDs, I'm using strings like "TPn", where n increments. In my balloon links, I'm linking to the fragment URLs such as href="#TPn-1" and href="TPn+1", ie TP2 links to TP1 and TP3, etc, and I account for both placemarks on the end so they don't have bad links to non-existent IDs. BTW, I've found when you do activate a link to a non-existent fragment URL, GE also decides to create a copy of the file, even if the file was loaded directly and not via a networklink, so you again have one point set laying on top of the other. However, I'm confident I have no bad links in this case.
Any light that can be shed would be appreciated. Or alternate ways of achieving my goals. I'm a KML newb after all and maybe there's something I'm doing wrong.
I suppose if I have to, I will sacrifice the balloon links. Being able to reload only one networklinks document for a collection of files + timed refresh + turning off flyToView are too desirable to lose now.
Thanks!
EDIT: Additional info - The duplicate document is created only when using balloon links. Clicking a link in the treeview under the placemark does not cause this anomaly. (In the code sample, remove the null Snippet element for each Placemark to see this effect.) Furthermore, it appears that a balloon link to ANY fragment URL causes the anomaly, such as a link back to a containing folder or document.
EDIT: Added 2 code samples. These are pared down to my essential needs, but still demonstrate the problem. Interesting to note the difference in the GE tree view when the data file 'document' element has an 'id' defined vs not, but it has no bearing on the problem. I prefer the look when the id is omitted.
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<!-- File is: C:\myTwoDataPoints.kml -->
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document id="myDoc">
<name>Two Points Doc Name Here</name>
<description>Doc Description Here</description>
<visibility>0</visibility>
<Snippet>Contains Two Data Points</Snippet>
<Style id="myStyle">
<BalloonStyle >
<text><![CDATA[Link To: $[description] ]]></text>
</BalloonStyle>
</Style>
<Folder>
<name>Points Folder</name>
<open>1</open>
<Placemark id="TP1">
<name>Miami, FL, USA</name>
<Snippet />
<description><![CDATA[New York]]></description>
<styleUrl>#myStyle</styleUrl>
<Point>
<coordinates>-80.226439,25.788969,0</coordinates>
</Point>
</Placemark>
<Placemark id="TP2">
<name>New York, NY, USA</name>
<Snippet />
<description><![CDATA[Miami]]></description>
<styleUrl>#myStyle</styleUrl>
<Point>
<coordinates>-74.005973,40.714353,0</coordinates>
</Point>
</Placemark>
</Folder>
</Document>
</kml>
and...
<?xml version="1.0" encoding="UTF-8"?>
<!-- File is: C:\myNetworkLink.kml -->
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document>
<name>NetworkLink Document Name Here</name>
<visibility>0</visibility>
<open>1</open>
<NetworkLink>
<name>NetworkLink Name Here</name>
<refreshVisibility>1</refreshVisibility>
<flyToView>0</flyToView>
<Link><href>file:///C:/myTwoDataPoints.kml</href></Link>
</NetworkLink>
</Document>
</kml>
I am creating a KMZ file as output from my program (using SharpKML). How can I set the initial view so that when this file is opened in Google Earth it centres and zooms around my data?
When I open a KML file in GE this behaviour is by default, but when I open my KMZ the browser just opens to the default whole world view centred on users country. If I double click the main KML within my KMZ file, then I get the correct zoom and centering around my data. How can I make this happen automatically when Google Earth loads the KMZ?
Thanks.
If you add a LookAt or Camera to the first element in your root KML file (first .kml file within your KMZ) Google Earth will start at that location when that file is loaded.
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2">
<Placemark>
<name>Google office</name>
<LookAt>
<longitude>-122.087387</longitude>
<latitude>37.422130</latitude>
<altitude>0</altitude>
<heading>-0.23</heading>
<tilt>47.81</tilt>
<range>115.5</range>
<gx:altitudeMode>relativeToSeaFloor</gx:altitudeMode>
</LookAt>
<Point>
<coordinates>-122.087461,37.422069</coordinates>
</Point>
</Placemark>
</kml>
If you have multiple features then add the <LookAt> to the root-level Document.
<kml>
<Document>
<LookAt>
...
</LookAt>
<Placemark>
</Placemark>
...
There is also a really easy way to do this in Google Earth/Google Earth pro:
Simply right click and bring up properties of the Folder in Places.
Go to the view tab and click the Snapshot current view.
Then save place as to update the kmz/kml.
This updates the <LookAt> at the level you click on- so for a point at the Placemark level or you can do it at the folder level.
I used to open my kmz files in Javascript and they would center automatically, but now as of a few weeks ago, my maps open up above the north pole. I created the kmz files so long ago I don't want to look at them or edit them. Is there some code I can add so that it works like it did before? I had before my open code
var overlay = new GGeoXml(\"http://www.mysite.com/data/file.kmz" ) ;
map.addOverlay( overlay ) ;
this bogus looking code that does not seem to initialze anything, but worked
var bounds = new GLatLngBounds();
// initialize bounds ??
var SWcorner= new GLatLng(parseFloat(87),parseFloat(-1));
var NEcorner= new GLatLng(parseFloat(89),parseFloat(1));
bounds.extend(SWcorner);
bounds.extend(NEcorner);
map.setCenter(new GLatLng(88.0, 0), map.getBoundsZoomLevel(bounds),
G_PHYSICAL_MAP);
I'm building an application that serves up data to a standalone Google Earth client. I want to send over an initial set of data, then update it dynamically using <NetworkLinkControl> and <Update><cookie> tags as things change on the server. I'm generating the KML using the Java API for KML (JAK) library. Unfortunately, while I can confirm that GE is refreshing my NetworkLink and pulling down the Updates I'm sending, none of my updates are showing up in GE. After lots of reading, it seems like it might be that the Update's <targetHref> might be the issue, but I'm 99.9% sure I'm sending over the same string.
Part of what has me confused is that I've seen conflicting info on whether or not the <cookie> element's value needs to be appended to <targetHref>. I did actually see one early prototype updating when I was serving up hand-written test KML files from a static server URL, so I suspect it's not. Actually, that's what's frustrating at the moment: I've seen updating work on my own machine, but can't get it working now with what looks like valid and correct KML.
The current setup looks like this (extraneous XML namespaces stripped for clarity; "$CLIENT_ID" is a GUID-like string):
Root KML file served from http://server/kml/${CLIENT_ID}:
<kml xmlns="http://www.opengis.net/kml/2.2"
xmlns:gx="http://www.google.com/kml/ext/2.2"
xmlns:atom="http://www.w3.org/2005/Atom"
xmlns:xal="urn:oasis:names:tc:ciq:xsdschema:xAL:2.0"><NetworkLink>
<Link>
<href>http://server/kmlupdates/${CLIENT_ID}</href>
<refreshMode>onInterval</refreshMode>
<refreshInterval>1.0</refreshInterval>
<viewRefreshTime>0.0</viewRefreshTime>
<viewBoundScale>0.0</viewBoundScale>
</Link>
</NetworkLink></kml>
Initial content KML served from http://server/kmlupdates/${CLIENT_ID}:
<kml><NetworkLinkControl>
<minRefreshPeriod>0.0</minRefreshPeriod>
<maxSessionLength>-1.0</maxSessionLength>
<cookie>cookie=0|kmlRequestType=updates|projectID=6|lastUpdateSeenIndex=-1</cookie>
</NetworkLinkControl>
<Document id="myProject">
<name>My ProjectProject</name>
<Placemark id="pm1"><name>point1</name>
<Point><coordinates>-117.0,35.0</coordinates></Point>
</Placemark>
</Document></kml>
Later update KML served from http://server/kmlupdates/${CLIENT_ID}:
<kml><NetworkLinkControl>
<minRefreshPeriod>0.0</minRefreshPeriod>
<maxSessionLength>-1.0</maxSessionLength>
<cookie>cookie=0|kmlRequestType=updates|projectID=6|lastUpdateSeenIndex=0</cookie>
<Update>
<targetHref>http://server/kmlupdates/${CLIENT_ID}</targetHref>
<Change>
<Placemark targetId="pm1">
<name>Name changed by Update Change</name>
</Placemark>
</Change>
</Update>
</NetworkLinkControl></kml>
If anyone has any suggestions on what I'm missing here, I'd greatly appreciate it. Thanks!
My original version of the question left out two facts that turned out to be relevant: 1) I'm using the Java API for KML to generate this, and 2) the XML namespaces inside <kml>. I finally figured this out after reading this Google KML Group post for the umpteenth time.
The problem is the last XML namespace, "xmlns:xal". For some reason, removing that from the KML allows the <Update> tags to actually change the items in Google Earth. JAK doesn't let you change the namespaces, but you can strip it manually from the marshaled string.
Absolutely bizarre, but at least I found a solution.
As per https://developers.google.com/kml/documentation/kmlreference:
<xal:AddressDetails> is used by KML for geocoding in Google Maps only.
Currently, Google Earth does not use this element; use <address> instead.
I have some sample using different approach to do something else here maybe related to yours (as your purpose "send over an initial set of data, then update it dynamically using tags") :
https://sites.google.com/site/canadadennischen888/home/kml/auto-refresh-3d-tracking
Approach is that all changes are from server Restful service. Hope it helps. Details as :
How to make a dynamic Auto refresh 3D Tracking :
prepare a RestFul service to generate KML file from DB (KML sample as inside above link)
My other jsp code will generate a KMZ file which has a link to my Restful service. KMZ file has onInterval ( as in the bottom)
Jsp web page allow user to download KMZ file.
When Google Earth open KMZ file, Google Earth will auto refresh to get new data from that Restful service
Everytime refreshing, server will send the latest update KML data with new data to GE.
KMZ sample:
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2" xmlns:gx="http://www.google.com/kml/ext/2.2"
xmlns:kml="http://www.opengis.net/kml/2.2" xmlns:atom="http://www.w3.org/2005/Atom">
<NetworkLink>
<name>Dennis_Chen_Canada#Hotmail.com</name>
<open>1</open>
<Link>
<href>http://localhost:9080/google-earth-project/rest/kml/10001/20002</href>
<refreshMode>onInterval</refreshMode>
</Link>
</NetworkLink>
</kml>
I am new to the KML format and try to figure out how to display a boat (a png), moving from a place to another along a path (a simple line drawn composed of several lines).
I can see how to display a Placemark, even with an icon, and a Path, separately.
What I would like to see when I click on the KML file is :
the boat appearing at the departure point;
the path drawing itself until the arrival;
the boat icon moving at a comfortable speed (bonus point it I can set a ration time / progress, extra bonus if I can click on start, pause or rewind) from departure to arrival along the path.
Is that even possible ? I know it is with Google Map, but you can program it with Javascript, which eases things a lot.
This is an old question, and there is now a better way to move a placemark (or even better a model) along a pre-determined linestring. Look into using this feature:
http://code.google.com/apis/kml/documentation/kmlreference.html#gxtrack
Sample code:
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2"
xmlns:gx="http://www.google.com/kml/ext/2.2">
<Folder>
<Placemark>
<gx:Track>
<when>2010-05-28T02:02:09Z</when>
<when>2010-05-28T02:02:35Z</when>
<when>2010-05-28T02:02:44Z</when>
<when>2010-05-28T02:02:53Z</when>
<when>2010-05-28T02:02:54Z</when>
<when>2010-05-28T02:02:55Z</when>
<when>2010-05-28T02:02:56Z</when>
<gx:coord>-122.207881 37.371915 156.000000</gx:coord>
<gx:coord>-122.205712 37.373288 152.000000</gx:coord>
<gx:coord>-122.204678 37.373939 147.000000</gx:coord>
<gx:coord>-122.203572 37.374630 142.199997</gx:coord>
<gx:coord>-122.203451 37.374706 141.800003</gx:coord>
<gx:coord>-122.203329 37.374780 141.199997</gx:coord>
<gx:coord>-122.203207 37.374857 140.199997</gx:coord>
</gx:Track>
</Placemark>
</Folder>
</kml>
The only way I've been able to make this work in static KML is to interpolate between the start and stop points and add placemarks for each frame I want to animate. So, from t=0 to t=1, draw a placemark at the start point. From t=1 to t=2, draw a placemark at the next point, etc.
This gives you the temporal player bar in Google Earth and you can rewind or advance the animation. However it is a little annoying because you wind up with every interpolation point in your placemark tree. Putting the placemarks in their own folder keeps them out of the way, but there's no way to hide them from the user.
Take a look at http://code.google.com/apis/kml/documentation/time.html#animating
The whale shark example does more or less what you want for the placemark. (The URL for the marker icon is broken). Animating the progress along the track can be done using the same trick.
If you want to try something much more difficult, you can try serving dynamic KML. Have Google Earth load a network link to your initial data. Then load another network link with an that sends an update for your placemark at every time tick.
http://code.google.com/apis/kml/documentation/kmlreference.html#link
http://code.google.com/apis/kml/documentation/updates.html
This approach has some serious disadvantages because it requires an external program to drive Google Earth and it does not give the user access to the built-in Google Earth temporal player bar. It also requires that all the data be loaded over a network link -- KML data from a file cannot be updated. That means your driver program needs to act as a http server. Also, in this model it is very hard to know exactly when Google Earth has finished loading and drawing the update. Really I don't recommend doing this; you can make it work using the Google Earth COM API, but it will always be a fragile solution.
There's a browser plug-in that lets you embed Google Earth into a browser page. From there you can use JavaScript to animate your placemark, change your paths, etc. Check out the Google Earth API Developer's Guide.
If you are going to display a boat on Google Earth, a 3D model would be a better approach then an image, since the users can change the viewing angle.
You might want to look into tours: http://code.google.com/apis/kml/documentation/touring.html
I've seen something like this done using a combination of (a number of) <gx:AnimatedUpdate> tags to move a previously created placemark representing your boat and <gx:FlyTo> tags to move the view (I think) all within a <gx:Playlist>.
Hope this helps.
I'm presuming this functionality did not exist when originally answered, but you can achieve the effect using a tour. The following shows a placemark moving in this fashion.
<?xml version="1.0" encoding="UTF-8"?>
<kml xmlns="http://www.opengis.net/kml/2.2"
xmlns:gx="http://www.google.com/kml/ext/2.2">
<Document>
<Placemark id="boat">
<Point>
<coordinates>0,0</coordinates>
</Point>
</Placemark>
<gx:Tour>
<name>Play me!</name>
<gx:Playlist>
<gx:FlyTo>
<gx:duration>5.0</gx:duration>
<LookAt>
<longitude>0</longitude>
<latitude>0</latitude>
<altitude>0</altitude>
<heading>-95</heading>
<tilt>65</tilt>
<range>250000</range>
<altitudeMode>relativeToGround</altitudeMode>
</LookAt>
</gx:FlyTo>
<gx:AnimatedUpdate>
<gx:duration>5.0</gx:duration>
<Update>
<targetHref/>
<Change>
<Placemark targetId="boat">
<Point>
<coordinates>1,1</coordinates>
</Point>
</Placemark>
</Change>
</Update>
</gx:AnimatedUpdate>
<gx:Wait>
<gx:duration>6.0</gx:duration>
</gx:Wait>
</gx:Playlist>
</gx:Tour>
</Document>
</kml>
The path could be marked with points whose visibility is altered by the tour at the appropriate time.
I have following sample in Google site. Hope this help.
(details inside : https://sites.google.com/site/canadadennischen888/home/kml/auto-refresh-3d-tracking)
prepare a RestFul service to generate KML file from DB
(sample as in https://sites.google.com/site/canadadennischen888/home/kml/3d-tracking)
My other code will generate a KMZ file which has a link to my Restful service
(sample as in this page)
KMZ file has onInterval
Web page allow user to download KMZ file which has URL that link to my Restful service
When Google Earth open KMZ file, Google Earth will auto refresh to get new data from that Restful service
Just google for "kml time animation"
KML: Time and Animation
KML: Animation
Animation and Dynamic Updates with KML