Tuesday, October 30, 2012

Cross Section Generator for Google Earth

Today I report on a nifty new tool from Mladen Dordevic of Declan de Paor's team at Old Dominion University for creating cross sections in Google Earth.  Cross sections have many applications from geology, geomorphology, archaeology and even meteorology.  However, putting them in Google Earth has always been a hassle requiring the messy creation of a sketchup model (if, like me, you're not well practiced using that tool) and export into Google Earth.

Screen shot of the tool in action in Hawaii
cross section image taken from here 

The tool:  What Mlarden has created is a tool for taking two images (one for the front, one for the back of a virtual billboard) and putting them back to back.  You get the ability to control yaw, pitch, orientation, height and width of your model (yaw and pitch are really difficult with a sketchup model).  The great thing about putting a cross section in Google Earth is that its in context - users can get a sense of location and scale of the cross section without even having to think about it.  The final step of creation is to generate a .kmz file that can be loaded into Google Earth outside of the API.

But there's more!  That would be more than enough but Mlarden's also cooked in a 'rising block' slider.  This allows for the cross section to be conjoured out of the ground by use of the tour controller once you've published your creation to .kmz.  It's my guess that a significant number of student users never quite grasp that a cross section is from below the ground, by providing a animation slider bottom left of the screen users get reminded of this.

Technical Info and the cloud:  This tool is produced by using the Google Earth API embedded into a web page.  Its a nice example of the power of the API to enable functionality not already in the Google Earth client but it's also 'in the cloud' in the sense that you upload your images and these can be shared with other users.

Bigger Teaching Picture  We could really do with more of these little tools making it easy to create sophisticated, often used elements in Google Earth.  Declan's team has been plugging away at this and when I get some time, I'll be reviewing some more of their work.

UPDATE 4 Nov 2012:  Apologies to both Declan and Mladen for not spelling their names right, now corrected.