Reconstruction from stereo plots

Introduction.

Often crystallographers dont make coordinates (which they obtained by using your and my tax money) available to the public. If, in those cases, there exists a stereo plot of the alpha carbon trace (for example a photograph made of a poster during a conference), it is in principle possible to reconstruct the three dimensional coordinates.

You need een PBM file of the ASCII type. You can recognize these by looking at the first line. This holds P1, P2, or P3 (P4, P5 or P6 for binary PBM files). You need a P1 variant.

Assume you start with a tiff file, than the following magic is required to make a PBM file:

convert -monochrome xxx.tiff xxx.pbm
pnmnoraw xxx.pbm > xxx_ascii.pbm
Convert is part of the Image Magik package, pnmnoraw is part of the pbn plus package. Ask your system manager about these software packages (or alternatives) if it is not installed on your machine.

Reading in the digitized file (GETDIG)

The command DIGIT will ask you for the name of the PBM file. This file will be read in, and stored in an internal value. This must always be the first command in a digi