Geoscience Reference
In-Depth Information
Data sources for MRDB generation are collected to fit into predefined
LoDs as far as possible. Every LoD without suitable data source has to be
generated from more detailed LoDs through generalization (
Figure 3
).
Figure 3:
Data integration scheme for multiscale mapping
While data for vector database layers is usually got from digital topo-
graphic maps, the sources for DEM generation excel in variety. Careful
analysis of existing data and results of related investigations (Doytsher and
Daliot 2009) reveal the difference in possible spatial resolutions of DEMs
from various data sources and therefore mapping scales (
Figure 4
).
Figure 4:
Various sources for DEM generation
However, the situation when every database LoD is supplied by fitting
source data is pretty rare. The problem becomes vital in small scales,
where no data with proper detailisation is usually available. Thus the task
of generalization remains the central issue of multiresolution database
preparation. Let's consider DEM generalization as most urgent for our
study.
