7
KODAK COLOR PLATES
Process E-2 and E-3
Temperature 75 F
Steps
Min.
1st Dev.
10
Rinse
1
Hardener
3
Wash
3
Reversal Exposure
1
Color
15
Wash
5
Clearing Bath
5
Rinse
1
Bleach
8
Rinse
1
Fixing
6
Wash
8
Stabilizer
1
TABLE 6
Photo grammetric Field Surveys
Color photography need no longer be considered as merely
an interpretative supplement to panchromatic photography.
With the materials and instruments now available, the entire
mapping job can be done in color and it is from this standpoint
that I shall discuss field surveys, aerotriangulation, and map
compilation.
Photogrammetric field surveys have three principal func
tions: to provide the basic and supplemental horizontal and
vertical control needed for aerotriangulation and map compila
tion; to identify control stations on the aerial photographs; and
to field edit, that is, to test and complete the compiled maps by
field examination.
Control identification is, primarily, a matter of selecting
small, well-defined ground features, identifying those features
on the aerial photographs, and then determining the position
and/or elevation of the identified objects. This procedure is
straightforward enough in principle but the selection of well-
defined small features and the exact identification of these
features on the photographs often leaves much to be desired.
High quality photographic prints and the stereoscopic exam
ination of those prints in the field are essential for the best work.
It has not been practicable to use color transparencies for field
work; consequently, if we are going to do a mapping job com
pletely in color, we must have good reflective type prints. We
are now able to produce adequate reflective type prints on a
production-line basis but it has been rather difficult to develop
the procedures. This will be less of a problem in the future
because the printing material is being rapidly improved.
Field edit or field completion is one of the more costly
phases of photogrammetric mapping. The superior interpre
tative quality of color photography has considerably reduced
the time that we must spend on field completion. Our experience
in this respect has been in mapping coastal features for nautical
charts and in preparing the special series of airport obstruction
charts. However, I am sure that color photography will also
greatly reduce the field edit costs in topographic mapping. The
U.S. Geological Survey is engaged in a rather extensive test of
color photography on topographic mapping and perhaps they
will have some comments at this meeting.
We rely to a great extent on color photography for mapping
complex coastal features such as those shown in Figures 1 and
6. Formerly, we had to walk most of this shoreline and examine
it in detail to clarify and interpret panchromatic photographs,
or we had to make a very extensive field edit. Our field work
included the location of aids to navigation and voluminous
clarification of shoreline details important to the charts. With
color photography much of this tedious and expensive field work
has been eliminated. Further, the color photography gives us a
great deal more underwater information about alongshore shal
low areas that are difficult for the hydrographer to reach.
Figures 7 to 11 and Figures 14 and 15 illustrate the interpre
tative qualities of color for coastal information.
Aerotriangulation
We have been performing aerotriangulation with color
diapositives since October, 1963, when Eastman Kodak Com-
P an Y gave us the first test plates. There have been some
difficulties in processing the plates, as I mentioned earlier, but we
have had no difficulty in handling the plates for aerotriangulation.
The whole matter is quite routine and the plates are handled
in the same way as panchromatic plates. We find a distinctive
advantage in color for aerotriangulation. The superior interpre
tative qualities enable us to make accurate readings on the pass
points used for connecting models, and this results in more ac
curate aerotriangulation. Color photography also permits the
operator to see better into shadows and is a great advantage in
finding those exact points identified by the field parties for
control of the aerotriangulation.
Stereoscopic Instrument Compilation
The real payoff in using color photography comes at this
stage of the process. The instrument operator sees more, inter
prets more readily, and thus makes a more complete map
compilation. This reduces field work as I mentioned in a pre
ceding statement. Figures 7 to 16 are illustrative of this fact
but you should also look at the color photography shown on the
plotting instruments on exhibit at this meeting.
We have recently started using color photography for the
preparation of Turbine Data Sheets and Airport Obstruction
Charts (Figures 4 and 5). These charts and Turbine Data Sheets
are not prepared for navigation but to provide information for
the regulation of the gross loading of aircraft in terms of the
lengths of runways, obstacles along the runway flight path, and
other factors. For example, in preparing these data for the
regulation of turbine powered aircraft operations we must find,
position, and determine the elevation of all objects along the
take-off flight path that project above a 2 l A% slope from the
end of each runway. Such objects are termed obstacles and they
must be found and positioned throughout the flight path area
for a distance of 20 miles from the end of the runway. Color
photography, with its superior interpretability, is proving to be
very advantageous for this program, particularly for finding,
identifying, and positioning the obstacles along the flight path.
Many of these obstacles consist of trees, often the highest tree
in a grove of trees. These are difficult to find and to locate
accurately by ground survey and so we use a combination of
ground survey, and stereoscopic viewing and measurement.
Color photography is particularly adaptable to this problem;
the many shades and hues of color enable us to see the tops of
