How are UV coordinates measured?

I've 开发者_StackOverflowgot a 3D modeling program exporting a UV mapped 3D model.

However the UV coordinates seem to be invalid or using a system I don't understand. I need help in understanding how UV coordinates map to the pixels of the bitmap (X, Y)

I've got a couple of textures in the range of 150x100 to 200x600. Here are some extracts:

    vt 1.04017 2.60853

    vt -208.397 776.637

    vt -0.984585 -0.0106576

    vt -208.397 32.6369

Based on the above data, considering the maximum measurable pixel is 600, are the 700+ UV coordinates wrapping back to the start of the image? And are the <0 UV coordinates measuring from the end of the image backward?

Yes, those values repeat the same image. Wrapping mode can be controlled in your code.