Sunday, September 30, 2007

Integrating your own gigapixel images in Google Earth

I have found that the processing necessary to integrate very large images in Google Earth 4.2 is, if not easy, possible.

All you need is create a version of your image padded to a power of two in both dimensions, then scale by 2 recursively until image fits in a 256x256 pixels tile.

Then you have to subdivide each image in single tiles.

Finally you have to create a suitable KML file.

The documentation for this feature can be found here.

I have some scripts that automate the process for a given TIFF image.

Saturday, September 22, 2007

Google Maps like nagivation of images

Viewing images on the Web is not always very user friendly, mainly because Web Browsers do not allow arbitrary zooming and panning in images.

A more and more common way to solve this problem is the use of JavaScript with custom nagigation of images, using concepts such as pyramidal organization of images.

A well known implementation of this concept is Google Maps.

While not directly related to very large images, because zooming does not refine information (images are not so-called very large), an interesting work has been conducted by Siva Dirisala, on a variety of Nasa images.

By using more and more of these ideas, we should expect more and more very large images (and more generally all images) to be really in-place zoomable, a nice addition to content of Web pages.