control survey is required for any mapping project, in most cases
the client utilizes their in house survey staff, if you require these
services P.T.I. can recommend competent individuals licensed to do
ground surveys by conventional survey methods or by use of GPS survey.
way P.T.I. will ensure that the density and location of the horizontal
and vertical control is properly established to maintain the project
order of accuracy.
large or remote land masses a combination of ground survey and analytical
photogrammetry can be used to minimize costs with no loss of accuracy.
P.T.I. will verify all horizontal and vertical ground control by means
of analytical triangulation.
computer printout showing the final deviations between ground and
photo position for each point is available as proof of ground control
Positional accuracy is a function of ground control survey accuracy
and how close the photogrammetrist can measure to the same image point
on the photograph.
of this the target shape, dimensions and clarity are extremely important
in the flight planning process, the target is composed of white painted
strips in the form of a "T X Y L of V". These paint strips
should be positioned clear from building overhang and clear from tree
cover as much as possible.
control survey using Global Position Systems (GPS) must have a clear
line of sight to 15 degrees from the horizon making choice of target
locations a critical part of the overall control network design.
Width in Inches