-11-
acy Phase B
or
1) Photomaps at scales 1:50,000 and 1:100.000 are assembled from the ortho-
photos and can be published as first provisional maps. They can serve as
43 base maps for resources surveys and also for the selection of areas of
urable which larger scale photography is considereà necessary for topographic or
rter other interpretation purposes, If desired, the application of pictomap
procedures can also be considered at this stage.
2) In an independent process, contours (contour interval 20 m) can be
erval constructed and scribed, using the drop line charts. These contours can be
printed over the first provisional (photo)maps.
la- e e 3) According to priorities, the following stages of perfection can then be
carried out for individual map sheets, in which photogrammetrio plotters are
no longer required.
em
a) On larger scale aerial photography or on the original small scale photo-
ly graphy under certain circumstances, a topographic office interpretation
is carried out with the aid of simple mirror stereoscopese
The results of this office interpretation are transferred to the original
photomaps printed on scribing sheets and are used for the production of
PS annotated photomapse
‚ES b) The office interpreted aerial photographs are then used in the field for
field identification and field completion. The results of this phase are
l also transferred to the original photomaps and are either used for the
jS production of a final annotated photomap or as desoribed in c).
c) After cartographic eneralisation, the results are used for the produe-
tion of a final multi-colour line-map at scales 1:50.000, 1:100,000 or
1:250.000.
e ©
A further improvement of the topographic map is possible, if, after establi-
shing geodetic height control and after re-adjusting the network of
APR-profiles to this control, contouring is carried out in photogrammetric
plotters. In this case, a contour-interval of 10 m can be obtained,
4. Comparative evaluation of cost and time requirements
The cost and time estimates will be confined to & comparison of the production
of line base maps (using the conventional system) and the production of photo
base maps as indicated in phase A of the proposed system. The estimates are
based on an area of 100 000 km“ and on the assumption that the final aim is
2 to produce a topographic base map at the scale 1:50.000.
0