1.1 Basic idea and main task of photogrammetry If you want to measure
the size of an object, let's say the length, width and height of a
house, then normally you will carry this out directly at the object. Now
imagine that the house didn't exist anymore - it was destroyed, but some
historic photos exist. Then, if you can determine the scale of the
photos, it must be pos- ble to get the desired data. Of course you can
use photos to get information about objects. This kind of - formation is
different: So, for example, you may receive qualitative data (the house
seems to be old, the walls are coloured light yellow) from photo
interpre- tion, or quantitative data like mentioned before (the house
has a base size of 8 by 6 meters) from photo measurement, or information
in addition to your background knowledge (the house has elements of the
"art nouveau" style, so may be c- th structed at the beginning of the 20
century), and so on.