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First order stereoautographs and the very accurate ones of the second order are generally used and to a 
great extent. Most of them have mechanical projektion. A few autographs with optical or optic-mechani- 
cal projektion are used in some countries. Ordinary autographs of the second order and simplified such 
instruments are used in some countries but only to a limited extent. 
Correcting devices for optical distortion are used in many countries. They are usually and to a great extent 
formed as compensation glass plates applied to a stereoautograph or to the equipment for the processing 
of diapositives. Some devices work mechanically and at the autographe. 
The usual method of relative orientation is the optical-mechanical one, according to von Gruber. It seems 
as if the question of relative orientation has been overemphasized earlier. 
Some further informations will be given in the following table, founded on the answers to the question- 
naire and the report to the 1958 Land-Survey Congress in The Netherlands. To facilitate a comparison the 
negative scales were normalized to the same focal-length 15 cm. Further the coefficients c, of the formula 
Sn = €, VS,. the coefficients cz of the formula d = c,- s, : 1000 (d in cm) and the coefficient cg of the 
formula m; = €, m, have been calculated. 
Some figures concerning international practice of stereoplottning for cadastral 
survey and reallotment. 
  
  
  
  
  
  
  
  
  
  
; : The scale of plan 1:sp 
Information 
1:500 | 1:100 | 1:200 | 1:4000 | 1:5000 1:10 000 
Negative scale 1:sn | 
(normalised to f — 15 em) .... — 6 000 —14 000,6 000 — 16 000 9 000—16 000,9 000—16 000 : 
Model scale 1:sm ............... 2000 |2 000 5 000 2 000—7 500 4 000—10 00015 000 — 20 000|10000 — 20000 
Coefficient c, in sn=c;\ Sp - 290 —195 175—715 150—150 175—130 
Contour interval meter ......... 0.5—1 1—2 1—3 2—5 2—15 5—15 
Signal dimension d em .......... 20—40 20—60 30— 70 40 —90 40 —120 60—150 
Coefficient c, in d. — c, - s,:1000 2.8— 6.5 2.5—6.3 13.2— 28.5 
Stand. dev. of control points 
Planimetry em............... 2—5 2—10 5— 15 5—20 10 —45 20—45 
Altimetry em .............s.. 2—5 2—10 5—15 5—20 10—35 20— 40 
Stand. dev. of signalized points 
In the field mp em. vs. 4— 10 5—15 5—20 10 —30 20—50 25—60 
In the negative NE 8—15 10—15 10— 20 10— 20 10— 20 15—50 
Altimetry cum... … 8—15 15 10—20 20 — 30 20 — 45 30 —50 
Stand. dev. of distances m, 
0— 10m em €... 4 6 8 10 15 25 
10— 30 m em... 5 7 10 13 18 30 
30—100 m em... ul. 6 9 12 15 20 35 
> 100 m CM ....... 8 10 14 18 25 40 
Coefficient c, in m, — c, - mp .... 0.8— 1.0 0.8— 1.2 0.8— 1.5 0.7 —1.0 0.5— 0.7 0.5 —1.0 
Plotting speed. including orienta- 
tion, planimetry, contours and 
preparing time .............. | 
Hectares per hour 0.3—1 0.5—5 1—5 4—20 5—30 10 — 100! 
(These figures from a large Swedish investigation) 
  
  
It must be stated here, that there is quite a small if any difference of accuracy (numerical and graphical) 
between first order stereoautographs and the precise ones of the second order. 
Signals were in most cases placed on pass-points and boundary-points in some cases only on pass-points. 
In a few countries however no signals were used. Germany has a good experience of centrally placed signals 
together with symmetrically arranged auxiliary identification signals with specified dimensions, Schirmer 
in Germany reported that only 6 ?/o of the signalized points could not be identified in the photographs 
(»Fünf Jahre Luftbildmessung in der Flurbereinigung Rheinland Pfalz. Zeitschrift für Vermessungswe- 
sen 1959. Page 434), 
Field completion survey seemed to be necessary for about 5% of the mapped area, but in cases where no 
signals were used up to 10 ?/o and in some cases 25 ?/o. Such a survey could be performed together with the 
preliminary field identification but was usually performed separately after the stereoplotting. Plane table 
and telecopic alidade with automatic reduction were used in most cases but also numerical geodetic 
methods. 
Graphical photogrammetry was the general method of surveying during the years 1956—1960. Numerical 
and analytical photogrammetry was used, it is true, but only to a little extent. It does not seem obvious 
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