Martin's Blog

Web GIS using ArcGIS Server

Here is a little ArcGIS Server Demo I had to do this semester. Feel free to play a little with it.
Note that there are lots of buttons and links that do nothing, because they are not implemented (due to missing time at the end)
Click on the image to go to the demo.

Adding custom maps to OSMdroid

Getting your own raster maps to display on an Android device should be pretty easy right? Well I found that it wasn’t quite that easy.
My first thought was to publish my map data on a Geoserver and serve the images via a WMS. It turns out Google does not want people to use their own WMS Overlays in Android. There are a few Tutorials out there with workarounds (for example here). Sadly these do not work very well.

After some testing and researching I came up with this solution to integrate bigger raster maps:

First step is of course to add geo-information to an existing image (if needed). This can easily be done using the georeference-plugin from Quantum GIS like so:

Now after you have set enough reference points go on and save the layer as a Geotiff image. Make sure to check “save .wld file” in the transformation properties.

When you have the .geotif file and its .wld file ready you have two choices. Either use Maptiler or upload the image to an instance of Geoserver, which will take over all transformations, and then download tiles via Mobile Atlas Creator – I choose the Geoserver way.

Once you have uploaded the raster file to Geoserver, you need to create a file in the “mapsources” folder of Mobile Atlas Creator. This will add your map to MOBAC. Name it whatever you want to. The Contents should look similar to those:

<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
	<customWmsMapSource>
  	<!-- Map source name as it appears in the map sources list.  Additionally used for the tile 		store name -->
  	<name>Mars</name> 

  	<minZoom>12</minZoom>
  	<maxZoom>18</maxZoom> 

  	<!-- Tile format (PNG, JPG or GIF) -->
 	 <tileType>PNG</tileType> 

  	<!-- WMS version -->
  	<version>1.1.0</version> 

  	<!-- WMS layer parameter -->x`
 	 <layers>MarsWorkspace:mars</layers> 

  	<!-- WMS base URL -->
  	<url>http://localhost:8080/geoserver/Mars/wms?</url> 

  	<!-- Corrently only EPSG:4326 is supported -->
  	<coordinatesystem>EPSG:4326</coordinatesystem> 

  	<!-- Optional: Additional parameters appended to the WMS url.  Don't forget to encode 	 amphersand characters to &amp; -->
  	<aditionalparameters>&amp;EXCEPTIONS=BLANK&amp;Styles=</aditionalparameters> 

	</customWmsMapSource>

The important thing here is, that you have specified your Geoserver address and the layer name.

When you have saved the file, you can start the Atlas Creator. Here just select your map service from the drop down list, the desired zoom levels and the area you want to export.

When you are ready add the selection to your atlas and create it. Mobac will generate an archive file containing folders for every zoom level containing all tiles. You now need to upload these folders to a web URL.

The implementation in osmdroid looks like this:

public void addTiledMaplayer(){
		final MapTileProviderBasic tileProvider = new MapTileProviderBasic(getApplicationContext());
		final ITileSource tileSource = new XYTileSource(layerName, null, 15, 16, 256, ".png",
			"http://url.with/tiles/");
		tileProvider.setTileSource(tileSource);
		final TilesOverlay tilesOverlay = new TilesOverlay(tileProvider, this.getBaseContext());
		tilesOverlay.setLoadingBackgroundColor(Color.TRANSPARENT);
		map.getOverlays().add(tilesOverlay);
		map.invalidate();

	}

Now you are done and hopefully everything works smooth.

Finally moved to new flat

My new room. Still updating on a few “constructions”, but so far feeling very good about it!

Photos from USA trip

I went to Washington and Las Vegas last month – managed to shoot a few nice images.

Fog in Münster

There was some heavy fog here yesterday, so I decided to take some pictures.

Finally found my old Noctu yoyo while moving out

I just love the looks of the bare aluminum.

Android App – Global Agenda Raid Timer

App showing Global Agenda mission countdowns.

Openlayers Overlays and SLDs

Here is a quick demo of Openlayers I used as a prototype in a paper to demonstrate decision support capabilities of semi-transparent map overlays.
Click on the image to proceed…

Feel free to have a look at my messy source code!