Reading in a binary grid file in Fortran 90 - multidimensional-array

Question

I'm having issues when trying to read in a binary file I've previously written into another program. I have been able to open it and read it to an array with out compilation errors, however, the array is not populated (all 0's). Any suggestions or thoughts would be great. Here is the open/read statement I'm using:
allocate(dummy(imax,jmax))
open(unit=io, file=trim(input), form='binary', access='stream', &
iostat=ioer, status='old', action='READWRITE')
if(ioer/=0) then
print*, 'Cannot open file'
else
print*,'success opening file'
end if
read(unit=io, fmt=*, iostat=ioer) dummy
j=0
k=0
size: do j=1, imax
do k=1, jmax
if(dummy(j,k) > 0.) print*,dummy(j,k)
end do
end do size
Please let me know if you need more info.
Here is how the file is originally written:
out_file = trim(output_dir)//'SEVIRI_FRP_.08deg_'//trim(season)//'.bin'
print*, out_file
print*, i_max,' i_max,',j_max,' j_max'
open (io, file = out_file, access = 'direct', status = 'replace', recl = i_max*j_max*4)
write(io, rec = 1) sev_frp
write(io, rec = 2) count_sev_frp
write(io, rec = 3) sum_sev_frp
check: do n=1, i_max
inna: do m=1, j_max
!if (sev_frp(n,m) > 0) print*, count_sev_frp(n,m)
end do inna
end do check
print*,'n-',n,'m-',m
close(io)

Answer 1

First of all the form takes two possible values as far as I know: "FORMATTED" or "UNFORMATTED".
Second, to read, you should use a open that is symmetric to the open statement that you used to write the file, Unless you know exactely what you are doing. I suggest that for reading, you open with:
open(unit=io, file=trim(input), access='direct', &
iostat=ioer, status='old', action='READ', recl = i_max*j_max*4)
That corresponds to the open statement that you used to save the file.

Answer 2

As innoSPG says, you have a mismatch in the way the file is written and how it is read.
An external file may be connected with one of three access methods: sequential; direct; stream. Further, a connection may be formatted or unformatted.
When the file is opened for writing it uses the direct access method with unformatted records. The records are unformatted because this is the default (in the abscence of the form= specifier).
When you open the file for reading you use the non-standard extension of form="binary" and stream access. There is possibly nothing wrong with this, but it does require care.
However, with the read statements you are using formatted (list-directed) input. This will not be allowed.
The way suggested in the previous answer, of using a similar access method and record length will require a further change to the code. [You'll also need to set the value of the record length somehow.]
Not only will you need to remove the format, to match the unformatted records written, but you'll want to use the rec= specifier to access the records of the file.
Finally, if you are using the iostat= specifier you really should check the resulting value.