Saturday 31 January 2009

Curious Google Earth snapshots

Google Earth has supposed a revolution to how we see the world, and here you acan find a video where some strange aerial pictures displayed by the Google Earth interface. Hope you enjoy it! (it's in Spanish, but an immage is worth more than a thousand words :-) )




Sunday 18 January 2009

KML and KMZ Benchmarking

When displaying data over Google Maps using KML and KMZ files there is always the doubt of whether it is better to use one type of file or the other. KML is the standard XML type file used by Google to display data over their maps, while KMZ is a compressed KML file. Compressing a KML file dramatically reduces its size, for example in the example used to a 26.22% of the original size, helping to save the typically scarce server space. Even though, less space does not always mean faster loading times, because it is necessary to uncompress the files, which may take a long time.

In order to find out which kind of file has a better performance and is best to work with, a benchmark test was performed. Results stated that between the moment a link was clicked in Google Maps and it fully opened in Google Earth the time elapsed was a 58.19% faster when using KMZ. The technical details of the benchmark test and the shape used to do the test can be seen under these lines.

File

KML

KMZ

Number of polygons

2103

Size in KB

5.705

1.496

Relative size (%)

100

26.22

Loading time (sec)

28.94

12.1

Relative time (%)

100

41.81

Software used

Google Earth

Version

4.2.0205.5730

OS

Windows XP SP2

Processor

Intel Pentium M 1.73 MHz

RAM

1GB

Web Browser

Internet Explorer

Connection speed

2MB/sec Cable

Files hosted at

www.gisngeo.com


This is the file used to do the benchmarking: