Interactive Scale-dependent multidimensional Point Data Selection using enhanced Polarization Transformation - Advances in Cartography and GIScience - page 403

285 points were kept. The results are shown in Table 6 and in Fig. 7 . The
density maps (density map of all points: Fig. 7a , density map of kept
points: Fig. 7b ) as well as the density values at the kept points do only
change slightly. The density distribution over the study area remains. In
Table 6 , 7 and 8 points were taken exemplary from the region displayed in
Figure 8 .

Figure 7: Density map of the original points (a) and of the kept points (b)

PRiQt QuPber deQsityB2rigiQaO pRiQt deQsityBseOected pRiQt differeQce

16 00609 00531 00078

29 00683 00581 00102

252 00718 00584 00134

255 00700 00565 00135

266 00620 00554 00066

273 00608 00544 00064

378 00737 00610 00127

Table 6: Results of the density-comparison of the original and the kept points

3.2 Comparison of the Relative Local Densities

The relative local densities were calculated for our test data set of 405
points whereby the initial scale of 1:1000 was reduced to 1:2000. Thereby
120 were deleted and 285 kept.

The arrays R_1 and R_2 , which contain all values of the relative density on
the initial and the reduced map, were computed.