(358) 
scales does the completion include control by theodolite traverse, levels or by 
planetable. 
In Switzerland for the Cadastral maps there is field examination before 
plotting (classification of roads, toponymy, etc.) and an examination after 
plotting; for the National topographic map there is only a qualitative and 
quantative examination after plotting with survey of any blank areas. 
In Italy, the IGM does all field completion before plotting for the 1: 
: 25,000 scale; the E.I.R.A. does field completion after plotting only in areas 
where there are uncertainties in the details plotted or gaps or heavy shadows in 
the coverage not permitting satisfactory plotting. At the Cadastral Service 
there is marking of the parcel boundaries before plotting, afterwards qualita- 
tive and quantitative examination. 
In Belgium the Public Works Ministry does all its field completion before 
plotting while the IGM does this for identification of details and toponymy 
and returns after plotting to verify small details. 
In the Netherlands field work both before and afterwards for the National 
Map; in the tropics only field work before plotting is done. 
In France the 1:20,000 map of France and 1 : 50,000 maps of N. Africa 
have completion surveys only after plotting while the 1 : 100,000 maps of the 
territories are plotted with preliminary field completion and published without 
further examination on the ground. 
Also to be reported here are the regular 1:100,000 surveys mady by the 
IGN of the very flat regions of Central Africa in the vicinity of Lake Tchad. 
The stereoscopic plotting could not furnish the relief because the slopes were 
extremely flat. Planimetric plotting was done directly at 1: 100,000 based on 
TPFR triangulation. After having experimented with several different simple 
procedures, (camera Lucida, pantograph) it was concluded that the most rapid 
and economical method was to use a stereoscopic plotter in which the prints 
themselves were set by a very quickly obtained approximate obsolute orien- 
tation. The speed of tracing approached 20 km? per hour. Heights were then 
obtained on the ground by levels for the flattest parts and the others by plane- 
table. 
In Sweden the two methods are used also: no advance field work on for 
1:10,000 or smaller scales advance work for cadastral scales. The Swedish 
Geographic Service does not do field completion after plotting. 
Finland is still experimenting and has not definitely adopted either method. 
In Austria until 1950, using the Multiplex, a very complete advance field 
examination was made. 
Since 1950, the use of stereoscopic plotters without anaglyphes has permit- 
ted replacement of this work by an identification study made in the office on 
enlargements of the negatives; after plotting there is a field completion which 
requires very little work. 
Apparently, on this question there is no uniformity of theory, but depend- 
ing on the country and the type of map, pre-completion or completion after 
plotting prevails and sometimes both are done for the same map. 
Results Obtained - Precision of the Surveys. 
It is very difficult to determine the precision obtained from the National 
Reports; some reports made no answer to this question as in the case of the 
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