Vector vs. Raster - when to use which?

[Redrobes]

A vector line is a math representation of a line with either two end points or one starting point and a direction - all just numbers.

Raster is a bunch of dots in a grid which have colors assigned to them to make up the image.

Rasterizing is where you go from something into a raster set of pixels. So what happens is that the app runs down the math line and colors in the dots. Its a little more complex than taking the closest and making it black on a white background for example as most measure the distances from the exact math line to the square pixel position and shade it darker the closer you are so it looks smoother and better.

So apps like say inkscape can export the math vector data to a raster version where it will do all that processing for you and leave you with a rastered bitmap - a rectangular set of pixels stored in a container like a JPG or a PNG.

Going the other way involves looking at the rectangular set of pixels and trying to best fit a line onto the darker pixels. Thats a more inexact science and different programs will give different results - some better than others.

[Gamerprinter]

Then of course, the exception to the rule, there's me and Xara.

Since Xara, though primarily a vector application has some hybrid raster operations built within it. I (as I always say) use Xara almost exclusively.

The question would be when do I use raster? Sometimes a texture is not condusive to my goals, so I image edit in PS or GIMP. I clean up images, alter colors, use cloner brushes to fix details. If I use 3D objects, which are rasterized before using them further, I do the fixes in PS/GIMP.

I almost never bring a map back into PS/GIMP to finish it. All compositing, texture filling, not to mention grids and labels are all done in vector.

I don't think I would ever totally create a map in GIMP - not my aesthetic or preferred method of operation.

I would like to learn to create bump maps better in GIMP, then I'd finish my maps by doing that - but that's the only thing I can think of to use GIMP as my final step in creating a map.

GP

[Redrobes]

Hmm ok better talk about texture mapping then. This is where you take a raster image and apply it into a vector space which is usually a 3D polygon for 3D models but it can also be a vector 2D area too.

What its essentially doing is resampling the raster texture but its not doing it with fixed scaling, the scaling is selected per pixel based on the vector shape so you can texture map a rectangular photo onto a circular disk for example. You can control the circle shape in a vector way and the image inside is a raster photo conforming to the shape of the circle.

I believe this is what Xara does and is what my ViewingDale does which allow both apps to scale up stuff using photo textures in a kind of vector way. In my opinion tho texture mapping is more of a raster process than a vector one. If you conform a low res photo into a shape and make that shape big then you will get the pixels showing up. If the photo was truly vectorized, which Xara can do very well too, then it would scale up perfectly but as said earlier it has to limit the colors and vectorize the bands within that photo instead of the full range of colors. So theres several options available but its just worth familiarizing yourself with all the options.