Which are Spatial Data?

1
Which are Spatial Data?

• Names
• email address
• NASA satellites imagery
• Weather and Climate Data
• SSN
• Medical Imaging
• NASA satellites imagery - terabytes of data per
  day
• Exercise Identify spatial and non-spatial data
  items in
• A phone book
• A cookbook with recipes

2
Difference between GIS and SDBMS

• GIS
• Focus on Algorithms
• Dataset is loaded to the main memory
• GIS is a top layer and use SDBMS
• Does not work well on JOIN operation with large
  set of objects
• File-based system (Layers)
• Does not have Concurrency Control, Index, and
  Query Processing
• SDBMS
• Focus on how data is stored and managed
• Dataset is located on the secondary storage
• SDBMS is a lower level
• Work well on JOIN operation with large set of
  objects
• Relational tables
• Concurrency Control, Index, and Query Processing

3
DBMS

• Persistence across failures
• Allows concurrent access to data
• Scalability to search queries on very large
  datasets which do not fit inside main memories of
  computers
• Efficient for non-spatial queries, but not for
  spatial queries
• DBMS ? SDBMS

4
Mapping ER Model to the Relational Model

• 1. Map each entity into a separate table,
  attributes become columns.
• 2. For 11 cardinality, place any one of the
  entities as a FK in the other relation.
• 3. For M1 cardinality, place PK of 1-side
  relation as a FK in the relation of M- side.
• 4. For MN cardinality, create a new relation
  with the PK consisting of the PKs of the
  participating entities.
• 5. For multivalued attribute, a new relation is
  created that has 2 columns key and multivalue
  attributes. Together key and multivalued
  attributes form PK.
• 6. For elevation attribute needs to be handled in
  the distinct manner. Since elevation is
  multivalued attribute, we need a new relation
  name Elevation. Because elevation captures height
  of the forest at different point (pointid), the
  new relation needs to have 3 attributes
  Forest-name, Elevation, pointid.

5
An Example World Database

• The World consists of three entities country,
  city and river.
• A country can have multiple capital cities and
  originate multiple rivers.
• A river is originated by one country.
• City is modeled as Point and has 3 attributes
  Name (PK), Population, and Capital.
• Country is modeled as Polygon and has 5
  attributes Name (PK), GDP, Population,
  Continent, and Life-Exp.
• River is modeled as line and has 2 attributes
  Name (PK), and Length.

6
An Example World Database

• Purpose Use an example database to learn query
  language SQL
• Conceptual Model
• 3 Entities Country, City, River
• 2 Relationships capital-of, originates-in
• Attributes listed in Figure 3.1