Ground Control Points (GCPs) are features on the ground that are clearly visible in aerial photographs (from aircraft or UAVs) or in ground or satellite imagery. These points are mapped on a coordinate grid in terms of both position and altitude.

These points may be characteristic natural points or points located on technical structures, in which case they are selected after the photogrammetry according to their location and whether they are sharp or not.

It is important for the accuracy of the photogrammetric rendering to follow that the photostats cover the boundaries of the overlapping part of the photocouples and the elevation limits of the area (highest and lowest point of the terrain) they cover.

Our company is certified for the procedures by which it carries out such studies with ISO 9001-2008 and undertakes the identification and mapping of photostats.

For greater accuracy and easier and more precise identification with the reproduced model of photostats, they can be realized on the ground before the photogrammetry with specific specifications and sizes depending on the scale of the aerial photographs to be taken.

Our company undertakes the realization and imaging of photostats throughout Greece with economical prices. For the mapping are used by the specialized crew equipped with GPS receivers of the latest technology.

The delivered products are:

• List including photostation number, measurement accuracy, coordinates f,l, altitude (latitude, longitude, ellipsoidheight) x, y, z (in EGSA’87 coordinates), date.
• Hand-drawn field sketch (delivered in GIF format) identifying the location of the photostat and useful comments and details on its capture.
• Digital ground photographs of the photographer in JPEG file format.