Improve fitmap error message when multiple maps fit

[olibclarke@…]

Begin forwarded message:

From: Oliver Clarke
Subject: [Chimera-users] Gaussian filter prior to fitmap?
Date: October 1, 2019 at 5:50:12 AM PDT
To: UCSF Chimera Mailing List <chimera-users@…>

Hi,

...

Also, when one wants to fit multiple maps to a single reference (quite common when inspecting results of 3D classification), Chimera gives an error message indicating that multiple maps have been input. There is an “eachmodel true” option one can set to allow fitting of multiple maps to a single reference, but the default value is false. It seems to me that the default value for this should be true, as if the user is specifying a wildcard or model ID range for the maps to fit, this is probably the behavior they are after I think. Or maybe the error message could be altered to indicate that if this is what one wants to do the eachmodel keyword needs to be specified?

Cheers
Oli

[Tom Goddard]

For your third issue of fitting multiple maps into a single map. I think the current fitmap option eachmodel has the right default of false because you are considering an uncommon fitting scenario. The fitmap command is mostly used for fitting atomic models in maps. Infrequently the atomic model may be a complex composed of 2 PDB models, like a small and large ribosomal unit that are each a separate PDB. If fit that in a map you usually want it fit as one rigid object "fit #1,​2 in #3" should move #1 and #2 rigidly together. If the eachmodel option defaulted true it would fit each model independently and in a low resolution map that will give the models right on top of each other in the highest density. We could have eachmodel default false when fitting atomic models and true for fitting maps -- it is a bit confusing. I think the best solution is as you suggest improve the error message. Currently ChimeraX "fit #1,​2 in #3" says "Multiple maps for #1,​2" and I can change that to "Need to use fitmap option "eachmodel true" or the sequence option to fit multiple maps". The sequential fitting fits each map as if it was a component of a complex, subtracting off the other map(s) first before fitting each in sequence. The sequence option may also be a more common case than the one you describe, fitting multiple different component maps in a single map.