2 bytes per cell, left to right scanlines.

Byte 1 is resource type:
if((b1>0x20)&&(b1<0x31))  fuel, b1-0x20 of it (0 thru 16)
if((b1>0x40)&&(b1<0x51))  gold
if((b1>0x80)&&(b1<0x91))  raw materials

Byte 2 is the player visibility bitmask.
bit 2 - Gray player surveyed this cell
bit 3 - Blue
bit 4 - Green
bit 5 - Red