GeoBI Architecture Based on Free Software: Experience and Review - Geographical Information Systems: Trends and Technologies - page 269

An interesting feature provided by GeoOLAP is the possibility of
combining two spatial hierarchies, as shown in Fig. 15. In this example, to
make the display simpler we chose only the total population of the Alajuela
province and combined two spatial hierarchies: administrative and health
divisions. Since this province belongs to four different Health regions, the
map in the Fig. 15 includes this division.
Fig. 15. Combining two spatial hierarchies of administrative and health divisions for the
Alajuela province.
Color image of this figure appears in the color plate section at the end of the topic.
Challenges in Research and Practice
Research related to spatial data warehouses (SDWs) and Spatial OLAP
(SOLAP) is not new. Research works started emerging at the end of the
1990s (Han et al. 1998), and their number increased in the following years.
Different aspects are considered, among others:
• Spatial dimensions and measures (e.g., Baltzer 2011; Fidalgo et al. 2004;
Gómez et al. 2009b; Han et al. 1998; Malinowski and Zimányi 2008;
Pourabbas 2003; Rivest et al. 2001; Silva, Times et al. 2008).
• Different types of spatial hierarchies (e.g., Baltzer 2011; Jensen et al.
2004; Malinowski and Zimányi 2008).