The target of this master's thesis was to study how digital aerial photographs can be used in road design process at the Road Administration. The images can be aerial photographs in central projection, orthophotos with coordinates or oblique photograps with optical axis being near horizontal position.
The four stages of a road design process are feasibility study, master plan, road design plan and construction plan. The conclusion of this study is that the digital orthophotos are in their best in the different steps of the master plan stage.
The main advantage of the orthophotos are that they are tied up to a coordinate system. It allowes scale determination, distance measurement and area determination. In addition they can be verified together with maps. Orthophotos in digital form can be processed by means of digital photo processing tools to extend the quality and characteristics of the photos.
There are four working scales of approach in general design. Number of details increases from scale to scale. The first scale gives a general view of the project area and the fourth scale the most detailed view of the smallest areas like private yards. When selecting images for the scales special attention was paid to the wishes and demands of the Road Administration. Important aspects are sizes of files, number of tones and scale and time of the photography.