Simulation of simultaneous heat and moisture transfer in soils heated by buried pipes

3. When a map, drawing or chart, etc., is part o f the material being photo­ graphed the photographer has followed a definite method in “sectioning” the material. It is customary to begin filming at the upper left hand comer of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again—beginning below the first row and continuing on until complete.