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We are beginning a project to visualize the results of a finite volume (FV) calculation using Google Earth. The FV data is essentially 2d (lat/long) data consisting of a Cartesian array of values (sea surface height, for example). Each value should be mapped to a color from some colormap, and then displayed as a single mesh cell in a gridded array suitable for Google Earth. The Cartesian array could be 100x100 or larger.

My question is, do we construct polygons for each mesh cell C_{ij} in the array, assigning a color corresponding to the q_{ij} value for that mesh cell? This would seem to create a huge KML file, if the coordinates of the four corners of every mesh cell must be described, (i.e. 10,000 polygons, for example).

Or are there KML tools we could use that would allow us to specify, for example, the lower and upper coordinates of the array, a generic mesh cell size (e.g. dX, dY values), and the array of q data (or, equivalently, colours) that should be used to fill the "patch"?

Alternatively, we could create an image file, containing for example, a rendered image of our data array (created by some other means), and then referenced from the KML file.

Our aim is to use PyKML for this project.

Any suggestions would be very helpful.

CodeMonkey
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Donna
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1 Answers1

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After much digging around, I think I now have a better understanding of what Google Earth can and cannot do, (or is not designed to do). It seems that Google Earth is not designed as a visualization tool for numerical data. This does not mean it cannot be done, but that one must create the image files elsewhere, and then overlay them onto Google Earth. For example, this link provides instructions for visualizing the output from a fire modeling code : 

      http://www.openwfm.org/wiki/Visualization_in_Google_Earth

The instructions here suggests how pseudocolor plots can used in at least one special case to visualize output in Google Earth.

Donna
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