These details did not jibe with the appearance of the camp in aerial photos flown in 1944. However, in reconstructing the camp, it was concluded that Wiernik's map showed things as they had actually were in its early history. 1940 German photos showed the original forest covering most of the camp's area. Photographs taken on the ground in 1942-43 by Kurt Franz showed that the gas chamber area had trees around it (see Section 4.0 below) - remnants of the woods shown on Wiernik's map, and which had vanished by 1944. Wiernik was also proved reliable in his drawing of the fence lines. The northern-most fence shown in his map turned out to still be visible as a cut through the woods when the 1944 aerial photography was examined stereoscopically. The fence had been constructed early in Treblinka's operation and then abandoned.
But the greatest value of Wiernik's map was to establish the credibility of his memory. This was useful in using pictures of the model of Treblinka that he built in the sixties which turned out to be reliable although not as an absolute depiction of the camp. Again the scales were misleading, but the relative positioning and shaping of fence lines could be relied upon. Wiernik's model and map were crucial in interpreting the aerial photography, and helped in identifying the site of the gas chambers with a high degree of confidence.
Many bits and pieces of evidence were similarly drawn on in analyzing the rest of the camp. In general, aerial photography formed the foundation for all conclusions. This was so both because it provided a geometric underpinning, and because many structures razed months before the coverage was flown could still be detected on the pictures. Ground photography was also correlated to the aerial photographs, thus affording a firm method of positioning structures and features appearing in the ground-level pictures. In some cases, individual trees, seen on the ground photos were identified on the aerial coverage, thus affording a means of positioning the buildings.
The primary materials used in reconstructing Treblinka were aerial photographs. Unfortunately, no coverage is known from the time of the camp's active period. Available aerial photography consists of captured Luftwaffe coverage flown between May and October 1944, a period encompassing a time after the camp's demolition while the area was still in German hands and during the subsequent capture of the region by the Red Army. The aerial photos formed the foundation used to identify the location and orientation of buildings present at the camp. This is so, even though most of the camp was obliterated as a result of the prisoner revolt in August of 1943, as a result of subsequent efforts by the Germans to obliterate traces, and because of further damage (burning) by the Red Army and perhaps by the local population in 1944-45. Aerial views often permit viewing retained traces of vanished structures and of previous activity which cannot be seen clearly, or at all, on the ground. At Treblinka, most of the buildings were not built on footings nor on any form of permanent foundation. The primary construction material was wood. When foundations were used at all, these consisted of wooden piers. Survivor accounts of the Jewish worker barracks, for example, describe the floor as being the local sandy soil itself. Only the more substantial buildings such as the new gas chambers, or the bakery were constructed of masonry built on a solid foundation. As a result, after Treblinka was razed, there were no easy clues to guide a researcher such as concrete footings or slabs. In the case of the gas chambers, the Germans went to considerable trouble by destroying the foundations and removing or burying the bricks from which the buildings were made. No direct trace of the gas chambers could be seen on the aerial coverage. Their location however was determined by detecting the remains of the tube's fence posts. Notable in the September aerial photograph are the faint scars that were left where vegetation had dried around the post holes. The aerial views contained many additional traces of former buildings in the form of faint tonal variations. These resulted from a number of possible causes: changes in the density of grass cover, soil color changes due to the presence of charcoal left after fires, soil compaction due to construction, etc.