Format of the binary *.plt file


The *.plt grid data files are the main enginees for ploting isocontour surfaces. The *.plt files can either be generated directly by various programs inside the gOpenMol package or be imported from other programs.

Programs inside gOpenMol generating *.plt grid data files:

To assist in moving the binary *.plt files between different hardware platforms the pltfile program is included. Using the program it is possible to format a binary grid file move it to an other platform and unformat the file again. The program can of course also be used interface the grid data from other programs with gOpenMol.

The *.plt file binary and formatted file formats are very simple but please observe that unformatted files written with a FORTRAN program are not pure binary files because there are file records between the values while pure binary files do not have any records between the values. gOpenMol should be able to figure out if the file is pure binary or FORTRAN unformatted but it is not very well tested.

Binary *.plt (grid) file format

Record number and meaning:

#1: Integer, rank value must always be = 3

#2: Integer, possible values are 1 ... 50. This value is not used but it should define the type of surface!

Values used (you can use your own value between 1... 50):

  1. : VSS surface
  2. : Orbital/density surface
  3. : Probe surface

Value 100 is reserved for grid data coming from OpenMol!

#3: Integer, number of points in z direction

#4: Integer, number of points in y direction

#5: Integer, number of points in x direction

#6: Float, zmin value

#7: Float, zmax value

#8: Float, ymin value

#9: Float, ymax value

#10: Float, xmin value

#11: Float, xmax value

#12 ... Float, grid data values running (x is inner loop, then y and last z):

  1. Loop in the z direction
  2. Loop in the y direction
  3. Loop in the x direction

The formatted (the first few lines) file can look like:


3 2
65 65 65
-3.300000e+001 3.200000e+001 -3.300000e+001 3.200000e+001 -3.300000e+001 3.200000e+001
-1.625609e+001 -1.644741e+001 -1.663923e+001 -1.683115e+001 -1.702274e+001 -1.721340e+001
-1.740280e+001 -1.759018e+001 -1.777478e+001 -1.795639e+001 -1.813387e+001 -1.830635e+001
...

Formatted *.plt (grid) file format

Line numbers and variables on the line:

#1: Integer, Integer. Rank and type of surface (rank is always = 3)

#2: Integer, Integer, Integer. Zdim, Ydim, Xdim (number of points in the z,y,x directions)

#3: Float, Float, Float, Float, Float, Float. Zmin, Zmax, Ymin, Ymax, Xmin,Xmax (min and max values)

#4: ... Float. Grid data values running (x is inner loop, then y and last z) with one or several values per line:

  1. Loop in the z direction
  2. Loop in the y direction
  3. Loop in the x direction

A file in this format can the be converted into binary with the pltfile program.

For an example of what a formatted *.plt file can look like please look above.

If you are a programmer please look at the included utility programs for the code for doing the reading and writing of *.plt files