Because, apparently, my knowledge about olfaction isn't as good as yours, would you be so kind to explain it on a bio-chemistrical level? And then explain how molecules, which are detected in the nose can give an answer on how far it is away?
Well, I dont know if MY knowledge of olfaction is any better than yours but try this one out:
There is far more information processing on the visual responses from your retina then just the raw data of what comes in through your pupils. The brain uses a bit of trig and your stereoscopic vision to work out distances to objects as well as past experiences of shadows, textures and memory of any recognisable object's size to give you information about depth. This processing is all done AFTER the cones and rods have triggered as a result of light hitting them which would be the eye's equivalent to molecules of smell hitting your sensory neurons.
What I'm getting at is that a 'visual image' of locations of objects would be a result of data analysis done after you've gathered the data. For example, maybe you could have stereo-olfactic depth information similar to stereoscopic vision. It could hook into your visual cues, connecting remembered smells with visible objects. Hell, it might even be a kind of overlay over your vision with a big red x saying "I think it's coming from here"
Another option would be for the visual representation to just be a series of colours and shapes to identify the molecular structure of the smell because our brains are more highly developed for pattern recognition in visual data then any other sense.