Creates a standard electron density file from external file formats. Example of reading in a CCP4 map. It has been edited to remove excess CCP4 listings.
% ../bin/mappage
*** Mappage program ****
Input map name from your crystallographic system: ano1.E
O style map name: q.map
Fourier parameters as read from the data-set
Origin ................................ 0 0 0
Extent ................................ 76 84 48
Grid .................................. 76 84 48
uvw (fast, medium, slow) .............. Z X Y
Do you wish to explicitly define Prod/Plus (y,[n])? n
Cell constants .................... 91.800 99.500 56.500 90.000 90
.000 90.000
Fourier type ......................N
Number of pages along x , y \& z 10 11 6
Byte = 327.670 * density + 18
vega [32]# di q.map
-rw-r----- 1 alwyn oteam 394752 Dec 15 15:48 q.map
vega [33]#
Notice the program decided on the prod and plus values. These numbers are to force the floating point number into a byte (i.e. an integer with values 1-255) via
byte_value = density_value * prod + plus
Any values outside the range are truncated. The plus value is therefore important when negative values are to be contoured, and the prod values is important for scaling.