The next data can be mentioned: 
ww : 
e 
allotment Heusden Vlijmen (29 km?) 
photoscale 1:20 000; flying-height 4200 m; map-scale 1:2 500; 
photogrammetrical mapping by Zeiss Stereoplanigraph, 
4 checking-lines were measured. The mean-error in the situation 
of intersection-points of these lines 1s respectively: 
0.5 m, 0,6 m, 0,55 m and 0,9 m. 
Re- allotment Maas en Waal (85 km?). 
photoscale 1:20 000; flying-height 4200 m; map-scale 1:2500; 
photogrammetrical mapping by Zeiss-Stereoplanigraph, 
3 checking-lines at a length of 2770, 1200 and 1290 m. 
The mean error is resp. 0,73 m; 0,45 m and 0,64 m. 
Re- allotment Mauriksche Wetering (44 km?) 
photoscale 1:20 000; flying-height 4200 m; map-scale 1:2500; 
photogrammetrical mapping by Zeiss-Stereoplanigraph, 
4 checking-lines of 1400, 580, 290 and 310 m. 
The mean error is resp. 0,60 m; 0,50 m; 0,25 m and 0,65 m. 
Re- allotment Walcheren (110 km?) 
photoscale 1:18 000; flying-height 3000 m; map-scale 1:2500; 
photogrammetrical mapping by Zeiss-Stereoplanigraph, 
An accuracy-research has not yet been finished. 
Re- allotment Maaskant West (33 km?) 
photoscale 1:10 000; flying-height 1500 m; map-scale 1:2500; 
photogrammetrical mapping by Zeiss-Stereoplanigraph, 
2 checking-lines at a length of 3100 and 2200 m. 
The mean error is resp. 0,6 and 0,8 m. 
Re- allotment Kampereiland (55 km?) 
photoscale 1:20 000; flying-height 4200 m; map-scale 1:2500; 
photogrammetrical mapping by Zeiss-Stereoplanigraph. 
An accuracy- research has not yet been finished. 
Generally the accuracy of the map is determined by the drawing- 
accuracy of + 0,2 mm. This finds expression in the above-mentioned 
examples. 
The mean error in the surface of the lots amounts to 0,30 %. 
In all 500 km? were plotted photogrammetrical since 1950. 
On the cadastarl-and re-allotment maps height data or contour lines 
are not recorded. Generally sufficient height data are available of these 
nearly flat grounds. All Dutch maps are based on the first- second- and 
third order triangulation (in stereographic projection). 
The cadastral photogrammetrical plotting is executed by the Sur- 
vey Dept. of the Ministry of Public Works (Geodetic Institute at Delft) 
— 83