re why does illustrator autotrace so poorly mac utkvx bitnet richard j mcdougald writes since there s no not really such thing as a decent raster to vector conversion program this tracing technique is about it simple stuff like b w logos etc do pretty well while more complicated stuff goes haywire the first and only thing i ve ever tried to auto trace was a piece of a uscg nautical chart using adobe illustrator i wanted to get the outline of the coast for western long island sound i was simultaneously suprised at how good a job it did and disappointed at how poorly it did i suspect what i gave it was a very difficult thing not only is the coastline very irregular but overlaid on the chart are numerous sets of gridlines not only lattitude and longitude but loran grids as well the most common mistake it make was whenever the coastline was roughly parallel and tangent to a grid line it would take off following the gridline instead of the coast i think the best improvement would be some sort of interactive algorithm that would let you step in and say no dummy you re going the wrong way steve reisberg a friend of mine a few years back did his doctoral work analysing electron micrographs of filimentous phage virii a good chunk of the work was writing a program to take a digitized micrograph and automatically trace the centerline of the virus particles this is essentially the same problem that illustrator tries to solve with its auto trace tool in some respects the problem steve worked on was harder since he was trying to do quantitative analysis of the virus structure and finding a good centerline was only the first step but a step on which all future analysis depended however in other respects it was an easier problem since the program could be written with a lot of knowledge about what the virus particles were supposed to look like and the analysis could be restricted to those particles which happend to be relatively straight clean and well imaged you don t always have that freedom auto tracing real life images in any case it gave me some insight into just how difficult this problem is to solve in the general case steve is no longer with us he and his wife disappeared while on vacation in hawaii a couple of years after they graduated their last known location was hiking in a densely wooded in a mountainous area while no bodies were ever found they are presumed to have been the victim of some sort of fall or accident in the woods roy smith roy nyu edu hippocrates project department of microbiology coles nyu school of medicine first avenue new york ny this never happened to bart simpson
