Transcript Databases and GIS

Benjamin Post
Cole Kelleher
1. Availability
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Data must maintain a specified level of availability to the users
2. Performance
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Database requests must be executed within time thresholds
3. Isolation between users
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Concurrency
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Commits/Rollbacks
4. Data Independence
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Reduces redundancy, storage requirements
5. Self-describing
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Able to describe the stored data using schemas
Comprised of relations between individual pieces of data
Concepts:
Table
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Also known as relation, contains attributes and tuples
Attributes
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Columns, stores the individual pieces of data
Tuples
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Rows, forms the relationship between the data in the columns.
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MUST BE UNIQUE ENTRY
Diagrams Entities and their Attributes, and the Relationship between entities.
Employee
Name
Start Date
Salary
1
Works at
N
Office Branch
Address
Office Hours
Office Phone
Comprised of objects stored in memory
Concepts:
State
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Defines information about the object, i.e. geographic location
Behaviors
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Actions that the object can perform or actions which modify an object
Inheritance
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Similar to Object-Oriented Programming, objectscan inherit state and behavior from other
objects
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Built on set theory and relational algebra
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Data definition language
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SQL can be used to define and create the database
Data manipulation language
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INSERT
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UPDATE
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DELETE
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Queries via SELECT
Geometries in Oracle Spatial are split into two data types:
1. SDO_GEOMETRY
• Stores the geometry as is.
• Requires a larger storage space due to redundancy.
• Useful for queries that retrieve the entire geometry of a feature.
2. SDO_TOPO_GEOMETRY
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Stores geometry using topological elements.
Allows for topology management over multiple features.
Decreased redundancy and thus decreased storage space.
Supports topological queries and processing
Oracle Spatial is an open format and is compliant on a large number of platforms.
Geometry data types are restricted to two dimensions.
GeoRaster in Oracle Spatial is used to handle raster data.
• Uses its own “GeoRaster” data type to standardize the rasters stored in the
database instead of storing the variety of raster file types that exist.
• Employs the SDO_GEORASTER data type for the storage of the raster data.
• Also uses the SDO_GEOMETRY data type to store the spatial extent of the raster
data for ease of indexing.
• This is a logically layered multidimensional data model that stores each raster
band as a layer.
• Further development needed in geoprocessing and modeling capabilities.
Post GIS is an extension of PostgreSQL for spatial databases.
• Certified under the OGC as a “Simple Features for SQL” database.
• Supports spatial joins in which two tables are joined on a spatial relationship.
• OGC compliancy means it is applicable to a large quantity of open source software and
some proprietary software.
• Further development is needed for three dimensional modeling and raster integration.
GRASS is an open source GIS package that can conduct spatial
analysis and modeling.
• Supports both vector and raster data with three dimensional capabilities.
• Is able to interact with a variety of useful software packages to aid statistical operations,
spatial analysis and processing.
• GRASS is OGC compliant which means its source code is available for the user to
manipulate to fit his or her needs and contribute to the software itself.
• High level interoperability means an increase in flexibility and performance.
• GRASS is able to connect to a variety of RDBMS for ease of integration.