Dear Tim, but probably I should adres this to Kai Diederichs, not including the resolution cutoff in COLSPOT and IDXREF is a feature of XDS I do not understand at all. For most cases, it may not matter since only the strong spots are used, but what are the advantages?
In fact there are disadvantages, especially when dealing with poorly diffracting difficult data sets: -when a crystallographer imposes a resolution limit, there are usually good reasons for it. -outside the resolution limit, there may be ice rings or contaminating salt spots, which make the autoindexing fail. -when processing 900 frame Pilatus data sets, running COLSPOT on the complete detector surface takes significantly longer then running it only on the center region. Of course, one could fudge a resolution cutoff by translating resolution into pixels and then calculating a TRUSTED_REGION, or manually editing the SPOT.XDS file, but this is a lot of extra and in my view unneccessary work. I would really consider using the resolution cutoff for COLSPOT as well. Best, Herman -----Original Message----- From: CCP4 bulletin board [mailto:CCP4BB@JISCMAIL.AC.UK] On Behalf Of Tim Gruene Sent: Tuesday, March 19, 2013 11:06 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Resolution limit of index in XDS -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Dear Niu, indexing relies on strong reflections only, that is (in very brieft) why INCLUDE_RESOLUTION_RANGE indeed does not affect the relections collected in COLSPOT which in turn are used by IDXREF. You can work around this, however, by making use of TRUSTED_REGION and set it to e.g. 0.7 or 0.6 (you can use adxv to translate resolution into pixel and then calculate the fraction you need to set the second number in TRUSTED_REGION to (or the first if you want to exclude the inner resolution reflections - I remember one data set where this was essential for indexing - DNA was involved there) Best, Tim On 03/19/2013 08:53 PM, Niu Tou wrote: > Dear All, > > Is there any command can set the resolution limit for index step in > XDS? I only found a keyword INCLUDE_RESOLUTION_RANGE, but it looks to > be a definition of resolution range after index step as it > says: > > INCLUDE_RESOLUTION_RANGE=20.0 0.0 !Angstroem; used by > DEFPIX,INTEGRATE,CORRECT > > Thanks! Niu > - -- Dr Tim Gruene Institut fuer anorganische Chemie Tammannstr. 4 D-37077 Goettingen GPG Key ID = A46BEE1A -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.12 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iD8DBQFRSOFJUxlJ7aRr7hoRAo6TAKC+BePgeODbDyngO7N8vCE4CnjxmQCfS5cP srShHNz1sDK0EMHSbE3fDwA= =kAwf -----END PGP SIGNATURE-----
