DRAFT DICTIONARY CBF/imgCIF Extensions Dictionary |
Draft version 1.5 for comment |
Description:
Data items in the ARRAY_DATA category are the containers for the array data items described in the category ARRAY_STRUCTURE. It is recognized that the data in this category needs to be used in two distinct ways. During a data collection the lack of ancillary data and timing constraints in processing data may dictate the need to make a 'miniCBF' nothing more than an essential minimum of information to record the results of the data collection. In that case it is proper to use the ARRAY_DATA category as a container for just a single image and a compacted, beam-line dependent list of data collection parameter values. In such a case, only the tags '_array_data.header_convention', '_array_data.header_contents' and '_array_data.data' need be populated. For full processing and archiving, most of the tags in this dictionary will need to be populated.Examples:
Example 1 -
This example shows two binary data blocks. The first one
was compressed by the CBF_CANONICAL compression algorithm and is
presented as hexadecimal data. The first character 'H' on the
data lines means hexadecimal. It could have been 'O' for octal
or 'D' for decimal. The second character on the line shows
the number of bytes in each word (in this case '4'), which then
requires eight hexadecimal digits per word. The third character
gives the order of octets within a word, in this case '<'
for the ordering 4321 (i.e. 'big-endian'). Alternatively, the
character '>' could have been used for the ordering 1234
(i.e. 'little-endian'). The block has a 'message digest'
to check the integrity of the data.
The second block is similar, but uses CBF_PACKED compression
and BASE64 encoding. Note that the size and the digest are
different.
loop_ _array_data.array_id _array_data.binary_id _array_data.data image_1 1 ; --CIF-BINARY-FORMAT-SECTION-- Content-Type: application/octet-stream; conversions="X-CBF_CANONICAL" Content-Transfer-Encoding: X-BASE16 X-Binary-Size: 3927126 X-Binary-ID: 1 Content-MD5: u2sTJEovAHkmkDjPi+gWsg== # Hexadecimal encoding, byte 0, byte order ...21 # H4< 0050B810 00000000 00000000 00000000 000F423F 00000000 00000000 ... .... --CIF-BINARY-FORMAT-SECTION---- ; image_2 2 ; --CIF-BINARY-FORMAT-SECTION-- Content-Type: application/octet-stream; conversions="X-CBF-PACKED" Content-Transfer-Encoding: BASE64 X-Binary-Size: 3745758 X-Binary-ID: 2 Content-MD5: 1zsJjWPfol2GYl2V+QSXrw== ELhQAAAAAAAA... ... --CIF-BINARY-FORMAT-SECTION---- ; |
Example 2 -
This example shows a single image in a miniCBF, provided by
E. Eikenberry. The entire CBF consists of one data block
containing one category and three tags. The CBFlib
program convert_miniCBF and a suitable template file
can be used to convert this miniCBF to a full imgCIF
file.
###CBF: VERSION 1.5 # CBF file written by CBFlib v0.7.8 data_insulin_pilatus6m _array_data.header_convention SLS_1.0 _array_data.header_contents ; # Detector: PILATUS 6M SN: 60-0001 # 2007/Jun/17 15:12:36.928 # Pixel_size 172e-6 m x 172e-6 m # Silicon sensor, thickness 0.000320 m # Exposure_time 0.995000 s # Exposure_period 1.000000 s # Tau = 194.0e-09 s # Count_cutoff 1048575 counts # Threshold_setting 5000 eV # Wavelength 1.2398 A # Energy_range (0, 0) eV # Detector_distance 0.15500 m # Detector_Voffset -0.01003 m # Beam_xy (1231.00, 1277.00) pixels # Flux 22487563295 ph/s # Filter_transmission 0.0008 # Start_angle 13.0000 deg. # Angle_increment 1.0000 deg. # Detector_2theta 0.0000 deg. # Polarization 0.990 # Alpha 0.0000 deg. # Kappa 0.0000 deg. # Phi 0.0000 deg. # Chi 0.0000 deg. # Oscillation_axis X, CW # N_oscillations 1 ; _array_data.data ; --CIF-BINARY-FORMAT-SECTION-- Content-Type: application/octet-stream; conversions="x-CBF_BYTE_OFFSET" Content-Transfer-Encoding: BINARY X-Binary-Size: 6247567 X-Binary-ID: 1 X-Binary-Element-Type: "signed 32-bit integer" X-Binary-Element-Byte-Order: LITTLE_ENDIAN Content-MD5: 8wO6i2+899lf5iO8QPdgrw== X-Binary-Number-of-Elements: 6224001 X-Binary-Size-Fastest-Dimension: 2463 X-Binary-Size-Second-Dimension: 2527 X-Binary-Size-Padding: 4095 ... --CIF-BINARY-FORMAT-SECTION---- ; |
Mandatory category: no
Copyright © 2005 International Union of Crystallography