3
Diapositive_printing: The various Wild instruments for
analytical or analog aerial triangulation and fcr detail
compilation from super uide angle photography use diapositives in
tuo sizes: the original 9" x 9" format, or half-size,
4-j" x A reduced format is also reguired for some ultra
uide angle plotters made by other manufacturers (e.g. Balplex
and the East German Zeiss Multiplex), uhereas some others
(e.g. Kern PG2, Kelsh, Aeromat) use 9" x 9" diapositives.
Whether full size or reduced, it is advisable to correct the
diapositives themselves for the effects of lens distortion
and also, in the case of smaller scales, of earth curvature
and atmospheric refraction, rather than to effect compen
sation in the plotter. This calls for the use of an optical
diapositive printer eguipped uith a set of correction plates
for eliminating RC9 distortion plus EC and AR for discrete
flying heights. This eguipment is available in the Wild U3A
and U4A Diapositive Printers, transformation range from 1:0.5
to 1:1.6, and the U3B and U4B models, range 1:0.31 to 1:0.55.
The U4-type printers are eguipped uith automatic electronic
dodging.
Preparation for aerial triangulation : Much of the time spent
in aerial triangulation on settings and measurements in the
comparator or the universal instrument can be saved by pre
vious selection and marking of the passpoints in the glass
diapositives under stereoscopic observation in the PUG3 Point
Transfer Device. Tie points along strip edges are transferred
to and marked on diapositives of the adjoining strip uith this
instrument. Points are marked by drilling a fine hole in the
emulsion.
Preparation for Compilation: In the case of small scale mapping,
compilation time can be saved by providing the plotter operator
uith a skeleton plan shouing the planimetric detail and the ge
neralization to be plotted. These plans are made on transparencies
(representing, for example, each neat model) overlaid on en
largements made uith the UG1 Enlarger or the E4 Enlarger-
Rectifier. This method uas used in the Bedford Experiment of
Commission E of the OEEPE.
