Figure 1 Linear and prediction interpolation. L is expressed in units 
of D as used for determinating the factor k from the vario- 
gram. 
EXAMPLE OF PLANNING THE SAMPLE SPACING 
A digital elevation model is to be constructed for an area characterised 
by three profiles of Table 2. 
The variograms are computed both by including and excluding disconti- 
nuities in the computation. The resulting variograms are plotted in 
Figure 2. 
The slopes 8 are 1.4 and 0.8 respectively. The constants Ks for a lag 
of 1 unit (equal to 100 meters) are 58 m? respectively 17 m?. 
Let the required accuracy of the elevation model be Onean ^ ^ meters. 
= 256 +