distance to the Meuse river; obtained by a spread
(spatial distance) GIS operation, from border of river; normalized to
$[0,1]$
ffreq
flooding frequency class, for definitions see this item in meuse; it is not known how this map was generated
part.a
arbitrary division of the area in two areas, a and b
part.b
see part.a
soil
soil type, for definitions see this item in meuse; it is questionable whether these data come from a real soil map, they do not match the published 1:50 000 map
Details
x and y are in RD New, the Dutch topographical map
coordinate system. Roger Bivand projected this to UTM in the
R-Grass interface package.