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KG2204 Exercise 3: KML and Google Maps

KML (Key Markup Language) and the compressed (zipped) version KMZ is used in for example the program Google Earth. The format is usable for spreading geographical information to persons without professional GIS programs. In this exercise we will export KMZ files from ArcMap, Read and create KMZ and KML files in Google Earth and also read and create KML files using Notepad.

Export from ArcMap

Download the file areas.shp (and associated files) here.

Save and extract the data on your computer and open it in ArcMap.

Give the layer the color you want and export it as a KMZ file using the tool:

ArcToolbox > Conversion Tools > To KML > Layer To KML

(output file name).kmz

Read and Create in Google Earth

Start Google Earth and open the KMZ file you exported from ArcMap using:

File > Open…

You can try to click at the polygons and see the associated attribute data.

It is also possible to edit existing KML/KMZ files or create new ones using Google Earth.

Create for example polygons using:

Add > Polygon

And draw a polygon.

If the sidebar is hidden, click:

View > Sidebar

In the sidebar you can put your polygon and other things you add into folders and also change name and properties.

When you have created a folder containing some different things in different colors, right click at the folder and click: Save Place As…

It is possible to choose if you want to save it as a KML or a KMZ. Save the folder you created using Google Earth both as a KML and a KMZ file.

Read and Create using Code (in Notepad)

The data in KML files following the structure of a code language called XML (eXtensible Markup Language). The structure is not only used for describing geographical data. Below is an example how to the region Scandinavia could be described using XML (not KML).

@@ <?xml version=“1.0” encoding=“UTF 8”?> <Region>

<Name>Scandinavia</Name>
<Country>
	<Name>Sweden</Name>
	<Population>9500000</Population>
</Country>
<Country>
	<Name>Norway</Name>
	<Population>5000000</Population>
</Country>
<Country>
	<Name>Denmark</Name>
	<Population>5500000</Population>
</Country>

</Region> @@

The first part tells the computer that this is XML code and also define the method (in this case UTF 8) of translating for example 00100100 (the binary code the data is build of):

The rest of the XML code is built on a hierarchical structure were parts start with &lt;xx&gt; and end with &lt;/xx&gt;.

Open in Notepad

Open Notepad and open your files:

File > Open…

Change Text Documents to All Files and open both the KML and the KMZ file you created in Google Earth.

The content of the KML file should exist of more symbols than the compressed KMZ file, but it is possible to read by a human.

Start with a new KML using Notepad

We will now create a new KML file using Notepad. Start from a empty Notepad document and state that this is a XML document by writing:

@@ <?xml version=“1.0” encoding=“UTF 8”?> @@

The second part starts the XML code. Copy this row to your document:

@@ <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”> @@

The third part is the actual information that in this case give coordinates for the point Subway.

@@ <Document>

<Placemark>
	<name>Subway</name>
	<Point>
		<coordinates>18.0547,59.3652,0</coordinates>
	</Point>
</Placemark>

</Document> @@

The last part end the KML code.

@@ </kml> @@

Save the file with the file extension .kml instead of .txt and open the file in Google Earth.

Create also a file with the same placemark but with one additional placemark named T Centralen and with the coordinates: 18.059, 59.331

Also save this file with the file extension .kml and open the file in Google Earth.

Add layers to Google Maps

Now we will import a KML/KMZ file into Google Maps and learn how to embed Google Maps into a webpage.

We need a Google account for this. Create a Google account if you don't already have one from before.

Google Maps has the following address: http://maps.google.com

Log in to your account and click on the question mark in the lower right corner, then Return to classic Google Maps.

Click on My Places and create a new map and give your map a name and import your KML/KMZ file you exported from ArcGIS by clicking at Import.

It is possible to edit the maps in Google Maps.

If you want to it is also embed the map into a webpage like below.

('Submit the code for embedding the map on Mondo!')

<iframe width=“425” height=“350” frameborder=“0” scrolling=“no” marginheight=“0” marginwidth=“0” src=“https://maps.google.com/maps/ms?t=h&amp;msa=0&amp;msid=212795148531545359520.0004cb1251cc0cf25a112&amp;source=embed&amp;ie=UTF8&amp;ll=59.359424,18.057747&amp;spn=0.015966,0.029655&amp;output=embed”></iframe><br /><small>View <a href=“https://maps.google.com/maps/ms?t=h&amp;msa=0&amp;msid=212795148531545359520.0004cb1251cc0cf25a112&amp;source=embed&amp;ie=UTF8&amp;ll=59.359424,18.057747&amp;spn=0.015966,0.029655” style=“color:#0000FF;text align:left”>Areas</a> in a larger map</small>

More about how KML files are built can be found here: https://developers.google.com/kml/documentation/

And more about XML can be found here: http://www.w3schools.com/xml/

kg2204_4.txt · Last modified: 2016/04/12 12:26 by ene