Earth land cover 32K virtual texture needs a host
Posted: 03.01.2004, 18:09
In the "32K Spec Map Case" thread, Buzz has pointed out a fantastic source of Earth Textures,
http://earthobservatory.nasa.gov/Newsroom/LCC/
This web site has a 1-km resolution map of the entire Earth, color-coded to reflect the land cover conditions in that square-kilometer. For example, various different types of forestation, or desert, or wetlands, or savanna, each have their own color. A key to the color coding is found on the above-cited web site.
I have created a 32K virtual texture based on this data. It uses 1024-pixel tiles in the PNG format. The entire texture is about 222M in size.
I believe that these images may be publically re-distributed, given that they come from NASA. If I am wrong about that, someone please let me know so I don't get myself in trouble.
I do not have any web space. If anyone wants to host this texture, I would be glad to upload it per your instructions.
It works very well as an overlay texture. It is also sort of interesting to use it as a primary surface texture with a high-res bump/normal map.
I had to make a difficult decision when re-sizing the texture. At its original 1-km resolution, the image was 43,200 pixels wide by 21,600 pixels tall. Each pixel represented the land cover of a square kilometer, in about ten discrete colors. When re-sizing (down-sizing), I had to decide how to handle these ten discrete colors. Did I want to ensure that every pixel still had one of the original ten colors? If so, when four pixels are down-scaled to one pixel, how do you decide which of the original four pixels' colors to use for the down-scaled single pixel? This seemed to be a problem without a good solution, so I finally decided to allow the resize program to blend colors, so that each new pixel is a blend of the colors of the original pixels. The downside of this is, as you zoom way in to the highest-resolution available, and then a little further, you will see plenty of pixels whose colors do not match any of those in the key.
Tim Crews
http://earthobservatory.nasa.gov/Newsroom/LCC/
This web site has a 1-km resolution map of the entire Earth, color-coded to reflect the land cover conditions in that square-kilometer. For example, various different types of forestation, or desert, or wetlands, or savanna, each have their own color. A key to the color coding is found on the above-cited web site.
I have created a 32K virtual texture based on this data. It uses 1024-pixel tiles in the PNG format. The entire texture is about 222M in size.
I believe that these images may be publically re-distributed, given that they come from NASA. If I am wrong about that, someone please let me know so I don't get myself in trouble.
I do not have any web space. If anyone wants to host this texture, I would be glad to upload it per your instructions.
It works very well as an overlay texture. It is also sort of interesting to use it as a primary surface texture with a high-res bump/normal map.
I had to make a difficult decision when re-sizing the texture. At its original 1-km resolution, the image was 43,200 pixels wide by 21,600 pixels tall. Each pixel represented the land cover of a square kilometer, in about ten discrete colors. When re-sizing (down-sizing), I had to decide how to handle these ten discrete colors. Did I want to ensure that every pixel still had one of the original ten colors? If so, when four pixels are down-scaled to one pixel, how do you decide which of the original four pixels' colors to use for the down-scaled single pixel? This seemed to be a problem without a good solution, so I finally decided to allow the resize program to blend colors, so that each new pixel is a blend of the colors of the original pixels. The downside of this is, as you zoom way in to the highest-resolution available, and then a little further, you will see plenty of pixels whose colors do not match any of those in the key.
Tim Crews