Spatial Data Warehouses - Data Warehouse Systems: Design and Implementation - page 460

11.8 What are the differences between a spatial level, a spatial level with
spatial attributes, and a nonspatial level with spatial attributes?
11.9 Give an example of each of the following spatial hierarchies: balanced,
unbalanced, and generalized hierarchies.
11.10 What is the difference between alternative and parallel spatial hierar-
chies?
11.11 Why are n -ary topological relationships needed in spatial facts? Are
such relationships usual in spatial databases?
11.12 How does a spatial measure differ from a numerical measure computed
with spatial operations? Does a spatial measure require to be related
to spatial dimensions?
11.13 Give an example of a multidimensional schema containing a spatial
measure. Transform the spatial measure into a spatial dimension.
Compare the two schemas with respect to the various queries that
can be addressed to them.
11.14 Define the geoid and the ellipsoid. What are they used for? What are
the differences between them? What is a datum?
11.15 What are SRSs?
11.16 What is the difference between the vector and the raster data models
for representing spatial data?
11.17 Describe the spatial data types implemented in SQL/MM.
11.18 Describe how field types are implemented in PostGIS. How does this
implementation differ from the abstract definition of field types?
11.19 Discuss the mapping rules for translating a spatial MultiDim schema
into a relational schema. State the advantages and disadvantages of
alternative mappings.
11.20 How is a topological relationship between spatial levels represented in
a logical schema?
11.21 How can one check in a logical schema the topological relationship of
afact?
11.22 Describe from a methodological perspective how spatial data can be
included in data warehouses.
11.12 Exercises
11.1 Consider the GeoFoodmart cube, whose schema is given in Fig. 11.19 .
Write in MDX the following queries:
(a) For each store, give the total sales to customers from the same city
as the store.
(b) For each store, obtain the ratio between the sales to customers from
the same state and its total sales in 2013.