Shot, deterrence was based on the known unknown. They knew but they knew not the detail. You could have argued that the depth of analysis was unnecessary.
In addition to the general detail of the targets they also created TARPA centered on each DGZ within each target area. This was latter amended when they realised that production of an analysis centered on ever target was too much and changed to ARPA*. This consisted of detailed base map and a series of overlays and associated data books. These contained detail of target structure and height. Using this it was possible to calculate the decibel level of its radar return compared to the background. A calm lake or river would be zero. A 3-4 story structure of steel or concrete may be 45 db, a perfect reflector contrast and ideal for direct radar attack or as an offset.
*TARGET AREA RADAR PREDICTION ANALYSIS