Virtual Very Large Images

While very large image typically waste a large amount of Hard Disk space, there is a category of very large images that are Virtual, that is computed on the fly.

The most common type of this is Fractal images. At a given resolution (zoom level) and position, you can get the tile image by computation.

Other that come to my mind are :

• Algorithmic images, such as an image that displays all possible 8 bits RGB colors.
• An image that displays all characters from the Unicode table. Each character can be made to fit one tile and rendered on the fly as it is needed.
• Rasterized images from vectorial description.
  

The Virtual Microscope

I have found another source for Very Large Images (or relatively large), NASA's funded project The Virtual Microscope.

It provides a large set of images, obtained through various microscopy methods, such as SEM.
The application is written in Java, with a nice small set of features (and an ugly look). The project images are delivered as Jars (aka Zip files), with subresolutions in subfolders, and individual tiles as single files. I have no idea why they did not use pyramidal TIFFs.

I do not know the data license, so I will not post VLIV images created from theirs, but it is easy to convert the Jars to single TIFFs suitable for VLIV.

VLIV released as freeware

The number of registered (paying) customers of VLIV is quite low (4 people in fact).
So I have decided to make it freeware, that is there is no need to register and the downloadable version is not limited in any way.

Registering is always possible and donations are encouraged if of course you like the program.

Estimating the dimension of Google Earth full resolution image

Above my home, the smallest detail I can spot on Google Earth for a pixel is about 10 cm.
The Earth equatorial circumference is about 40 000 kilometers.
This makes 40 000 * 10 000 = 400 000 000 pixels.
Assuming the Earth is spheric and the Google has all data, this makes 400 000 000 * 200 000 000 = 80 000 000 000 000 000 pixels, much more Gigapixels that I can imagine.

Of course I do not think data is available at this resolution for the whole Earth, and my estimation of precision can be wrong, but these numbers are mind-boggling.

The most precise satellite image of the Earth I have is about 1 pixel for 500 meters, this already makes a 86400 * 43200 image.

Download the NASA Blue Marble NG pyramidal TIFF

I know seeing is believing. Unless you actually see one gigapixel pyramidal image viewed by VLIV, you will not really understand how nice it is. This is why I have made the NASA Blue Marble NG image downloadable here.

Be warned, it's a large image (427,582,365 bytes). It contains all 8 resolutions from 86400x43200 pixels down to 675x337 pixels.

In order to keep the image size reasonable, an aggressive JPEG compression has been conducted, so there are some artifact you would not experience on lossless compressed image.