You need to specify the cell for the map. This can be done by editing the CRYST1 card in the pdb header - presumably to be 307.2 307.2 307.2 etc..
If that is done and tou use grid 128 128 128 that is another way to get the desired pixcel size Eleanor On 15 October 2014 10:22, Kevin Cowtan <[email protected]> wrote: > I'm not sure, but I think you'll have to do a 'run and edit command file' > and add the following keyword: > GRID SPACING 2.4 2.4 2.4 > > Give it a try. > > On 14 October 2014 17:31, Steven Chou <[email protected]> wrote: > >> Dear All, >> I'm trying to generate a mask from a pdb coordinate file using the >> 'Ncsmask' utility of CCP4 (Map & Mask Utilities => Create/Edit Masks). >> The parameters I used are: >> ========================================= >> Radius for building mask from atoms 10.0 angstrom. >> Space group P1 >> Set map extent x 0.0 307.2, y 0.0 307.2, z 0.0 307.2 >> Set map grid x=128 y=128 z=128 >> >> Cleanup mask to have 1 contiguous region >> Trim maks to minimum box >> ========================================= >> I want to have a mask with pixel size of 307.2/128 =2.4, and box size of >> 128. >> >> But the mask I got has a pixel size of 1 A/pixel, and box size of 308. >> >> Is there anything wrong with my parameters? >> It seems that the mask generated by Ncsmask always has a pixel size of 1. >> >> Thanks in advance! >> Steven >> >> >> >> >> >> > > > -- > EMAIL DISCLAIMER: http://www.york.ac.uk/docs/disclaimer/email.htm >
