Use binary file access, makes things easier and faster.

VB Code:
  1. 'Write

  2. Open Filename For Binary As Filenumber

  3.    For i = 0 To UBound(mbytMap, 1) 

  4.       For j = 0 To UBound(mbytMap, 2) 

  5.          Put Filenumber ,, mbytMap(i, j) 

  6.       Next

  7.    Next

  8. Close Filenumber

  9.  
  10. 'Read

  11. Open Filename For Binary As Filenumber

  12.    For i = 0 To UBound(mbytMap, 1) 

  13.       For j = 0 To UBound(mbytMap, 2) 

  14.          Get Filenumber ,, mbytMap(i, j) 

  15.       Next

  16.    Next

  17. Close Filenumber

I also recommend you to save the map dimensions just before the map data (so you have no fixed size). Note that you'll have to ReDim the map array before reading the data!