[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
imgCIF / CBF (fwd)
- To: Multiple recipients of list <email@example.com>
- Subject: imgCIF / CBF (fwd)
- From: "I. David Brown" <firstname.lastname@example.org.McMaster.CA>
- Date: Fri, 11 Dec 1998 14:22:41 GMT
Dear Colleagues, I am circulating a report on the imgCIF/CBF project that I have received from Andy Hammersley. This project started as an attempt to write a dictionary for storing images from image plates. It ran afoul of Comcifs rules because the working group was unanimous that the image had to be stored in a binary file which contravenes the basic rule of STAR. The compromise that has been worked out is that the standard will define two files, a Crystallographic Binary File (CBF) and a cif compliant imgCIF (imageCIF). The two standards are identical except that the image itself will be written in binary in CBF and in ASCII in imgCIF. Thus translation of a file between these formats will be relatively straightforward. Herb Bernstein has been doing noble work in ensuring the interconvertability of the two files and ensuring cif compliance. The binary form was deemed necessary for efficiency in transferring files (expected to be its primary function) but imgCIF would be used for long term archiving. Although designed with image plates in mind, the standard can be used to transfer or archive any images. As you can see from the report below, we can expect this dictionary to come for tentative approval during the next few months. I will remind you that the msCIF (modulated structures) dictionary is also expected to be presented for tentative approval at about the same time. Best wishes David More below: ***************************************************** Dr.I.David Brown, Professor Emeritus Brockhouse Institute for Materials Research, McMaster University, Hamilton, Ontario, Canada Tel: 1-(905)-525-9140 ext 24710 Fax: 1-(905)-521-2773 email@example.com ***************************************************** Dear David, I asked other members of our informal group for comments on the report on the status of imgCIF/CBF. Herb provided an excellent response, which I'm sure we're all happy with. I include this in its entirety. Perhaps, I'd just like to emphasise that "imageNCIF is dead, long live imgCIF". Herb has done an excellent job in providing software to write images in pure ASCII CIF form. In fact he allows a whole range of encoding and translation possibilities. Such a file has (I believe) every right to be considered a CIF. Thus I suggest that "imgCIF" is presented as a fully compliant CIF dictionary. Best Regards, Andy ---------------------------------------------------------------------------- Herb's suggestion: ------------------ Dear David, We are pleased to report excellent progress on CBF/imgCIF (the new name for imgNCIF). In the course of our discussions, we have come to the conclusion that there is no reason not to consider our efforts part of the CIF effort. On the contrary, if the IUCR and COMCIFS are agreeable, we would very much like to have CBF/imgCIF be considered part of CIF. We are working on our dictionary with an eye to submitting it for COMCIFS approval in the near future, so that it could be discussed in Glasgow. We understand that the binary aspects of our work (CBF) cannot be considered part of a "true" CIF, but the ascii side (imgCIF) is intended to be fully CIF compliant, and both sides share exactly the same dictionary of tags, with the ability for faithful translation in both directions. We hope that what we are doing may prove useful for other CIF-based efforts in need of a reliable way to translate to and from binary representations. We have some more work to do before we submit what we have done to COMCIFS, but here is where things now stand: 1. The dictionary has been augmented to cover the tags necessary for representation of image data. We still need to add tags to represent diffraction geometry. 2. A test-version of an API has been written by Paul Ellis and Herbert Bernstein. There are some efficiency improvements needed, and there are two more compression formats that need to be coded. Paul is still looking at some changes recently made by Herbert, so the next version is not quite ready for distribution, but it can be seen in its current state (along with the current state of the dictionary) at http://www.bernstein-plus-sons.com/software/CBF 3. We hope to resolve most of the open questions over the next few weeks, and be ready to submit a dictionary to COMCIFS in February.