Fig. 4 
Comparison 
of Procedures Il and Ill 
1. Duration and Costs 
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
  
Duration of work ; 
Nos. | Kind of work (in days) Costs (n DND 
Proc. Il | Proc. Ill | Proc. ll | Proc. Ill 
2. Completeness in the Acquisition of Map Features 
Cartographic : 
1a work before field 73 14 230,- Proc. Il P ul 
x : roc. 
checking Nos. | Elements c 
(1:5000) | (Planicart) 
Preparatory and SA: o o 
75 photogrammetric 1 es 1 Buildings 96 % 92 % 
work preceding © 2 Lines of communication 69 96 69 96 
field checking 8 | Land use 54 96 94 96 
2 Field checking 7 5 2 900,- 2 050,- 4 Individual symbols 43 % 29 % 
5 Planimetry to be 67 % 92 % 
Cartographic eliminated 
3 work 14 69 3000,- | 11 900,- 
Repro-technical : 
4 Lou 3 500,- 900,- Fig. 5b 
Total 94 91 23 630,- | 20700,- 
Fig. 5a 
At the present state of the technical evolution, procedure III seems to me therefore to be 
superior to the other procedures, and for economic and technical reasons especially suited for 
the revision of our map series 1:25 000 and 1:50 000. 
After this result we intend, in the future, to limit the working areas for the yearly revi- 
sion by units of the Topographic Map 1:100 000 and consequently to combine the revision of the map 
scales 1:25 000, 1:50 000, and 1:100 000. Thereby the photo flight will become more economic. The 
stereo-photogrammetric plotting can be used for the three scales. For the scale 1:100000 the can 
plotting will be reduced and somewhat revised. As a result, the three most important map scales 
be revised side by side nearly at the same time even though a small postponement may be necessary. 
8. - Cartographic and Repro-Technical Works 
  
In different publications [5] I have repeatedly stressed that in map revision we must above 
all shorten and rationalize the cartographic work, because this requires by far most of the time. 
In our Topographic Map 1:25 000 revision, about 65 % to 75 % of the work is the cartographic part. 
At long sight only automation will also help us in cartographic revision work in a decisive 
manner. Considering this knowledge, we have made two tests in the State Survey Office of North- 
rhine-Westphalia. Originally both tests aimed at remaking of the map 1:25 000. For both tests 
aerial photographs 1:5 000 reduced to 1:10 000 constituted the base material. In both tests very 
simple drafts had been prepared on these photo maps 1:10 000. 
The first test has shown, that it is quite possible with the existing means to scribe and to 
draw respectively a topographic map 1:25 000 nearly fully automatically by way of digitizing a draft. 
Only minor modifications of the existing sample sheet are necessary. This test, however, has also 
demonstrated, that at present, it is still neither useful nor economic to prepare a topographic map 
in this way. The expenditure of time is still too large, as long as each individual symbol has to be 
drawn or scribed and cannot be projected. 
The second test should therefore combine all existing procedures with automatic scribing, 
in such a way that each procedure can be applied where its efficiency is optimal. Line elements, 
as e.g. roads have been scribed automatically, symbols as e.g. trees, slopes were transferred 
by the rubbing or pressing down method, aerial covers have been produced by stripping. This doing, 
the existing drawing specifications should be observed, so that the new sheet fits exactly to the 
existing map series. 
- 55 =