<input file> | 3D map to work with |
<A/pix> | Angstroms/voxel in the map |
[thr=<thresh>] | Calculate the volume/mass at a given threshold |
[calc=<mass>] | Determine the threshold for a given mass |
[set=<mass>] | Rescale the map densities so a threshold of 1 gives the specified mass |
[plot] | Output a x/y file containing a plot of threshold vs mass |
volume threed.1a.mrc 4.667 set=2500
This routine calculates volumes enclosed by isosurfaces. The algorithm used is approximate. It doesn't calculate subvoxel volumes. It is fairly accurate as long as a substantial fraction of the voxels are 'inside' the volume.
For convenience, mass is specified rather than volume. Volume/mass conversions assume a density of 1.35 Da/A^3.