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Data Acquisition and Management�Unit 4 – Data Design in the Geodatabase� � �

Empowering Colleges:

Growing the Workforce

Based upon work supported by the National Science Foundation under Grants DUE 1304591, DUE 164409, DUE 1700496, DUE 1937177, Due 1938717 DUE 1937237, 2030206 and 2015927. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the views of the National Science Foundation.

Author: Wing Cheung

Title: Professor, Palomar College

Assistant Director, GeoTech Center

Email: wcheung@palomar.edu

​

Source: ClipArtKey

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Basic feature class properties

  • Spatial reference information
  • Geometry/shape
  • Attribute data

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Basic feature class properties

  • Geometry/shape types
    • Point
    • Multipoint
    • Polyline
    • Polygon

Source: Esri

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Basic feature class properties

  • Attribute data types
    • Number*
    • Text
    • Date (and time)
    • BLOB
    • Raster

Source: imdb

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Types of number

  • Whole (e.g. 5)
    • Short integer
    • Long integer
  • Decimal (e.g. 5.65)
    • Float
    • Double
  • Precision: digits
  • Scale: decimal places

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Types of number

Data type

Storable range

Storage size (bytes)

Short integer

-32,768 to 32,767

2

Long integer

-2,147,483,648 to 2,147,483,647

4

Float

Approximately -3.4E38 to 1.2E38

4

Double

Approximately -2.2E308 to 1.8E308

8

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Advanced feature class properties

  • Subtypes
  • Domains
  • Relationship class
    • Feature(s) - feature(s)
    • Feature(s) - object(s)

​

Source: (Zeiler, 2000)

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SUBTYPES

AN ATTRIBUTE THAT ALLOWS YOU TO DIFFERENTIATE AND GROUP FEATURES IN YOUR LAYER INTO CLASSES

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Subtypes

  • Subtype field
    • Stores code to differentiate classes
    • Must be integer data type
    • Default subtype value for new features

Source: (Zeiler, 2000)

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Subtypes

  • When to subtype?
    • Thematically similar features (roads) with different characteristics (material)
    • Improved performance
  • When not to subtype?
    • Features of different themes with different attributes (roads, rivers, powerlines)
    • Cannot limit access to one subtype

​

Source: (Zeiler, 2000)

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Subtypes

The Code field is our subtype field with the Short Integer data type. It is used to differentiate between thematically similar features (beer-related) with different characteristics (1-brewpubs, 2-microbreweries, etc…)

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DOMAINS

CONSTRAINTS ON WHAT CAN BE ENTERED INTO THE ATTRIBUTE TABLE

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Attribute domains

  • Coded values (stop, beach crossing, yield, etc.)
    • Number, text fields
  • Range (1 to 6 lanes)
    • Number, date fields

​

​

​

Source: WeHeartIt.com

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Attribute domains

​

  • Spilt policy
    • Default
    • Duplicate
    • Geometry ratio
  • Merge policy
    • Default
    • Sum values
    • Area weighted

​

​

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Attribute domains: Split policy

Source: (Zeiler, 2000)

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Attribute domains: Merge policy

Source: (Zeiler, 2000)

(0.35*24000+0.47*45000)/(24000+45000) = 0.43

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RELATIONSHIP CLASSES

ASSOCIATIONS BETWEEN SPATIAL AND NONSPATIAL OBJECTS IN GIS

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Relationship classes

​

  • Defining the association
    • Origin class (primary key) vs. Destination class (foreign key)

​

​

​

​

​

Source: (Zeiler, 2000)

Primary Key

Foreign Key

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Relationship classes

​

  • Simple vs. composite relationship
  • Composite: origin class has all the control

​

​

​

​

​

Source: (Zeiler, 2000)

Foreign Key

Source: (Esri)

COMPOSITE

When the pole (origin) is deleted, the transformers (destination) are also deleted.

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Relationship classes

​

  • Cardinality
    • 1:1, 1:M, M:1, M:M

​

​

​

​

​

  • Naming convention
    • Origin [has/have] Destination
    • Pluralize, Has vs. Have

Source: (Zeiler, 2000)

(1:1) StudentHasID

​

Each student has one ID

(M:1) StudentsHaveAddress

​

Many students (e.g. sibling) (may) have the same address

(M:M) StudentsHaveClasses

​

Many students (may be) in one class, and one student (may) takes many classes

(1:M) StudentHasEmailAdds

​

Each student (may) has many email addresses

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Relationship classes: Feature-linked annotation (label) example

Source: (Zeiler, 2000)

3. Origin or Destination?

2. Origin or Destination?

1. Simple or Composite relationship?

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Relationship classes: Feature-linked annotation (label) example

Source: (Zeiler, 2000)

3. Origin or Destination?

2. Origin or Destination?

1. Simple or Composite relationship?

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Relationship classes: Feature-linked annotation (label) example

Source: (Zeiler, 2000)

3. Origin or Destination?

2. Origin or Destination?

1. Simple or Composite relationship?

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Conclusion

  • Basic and advanced feature class properties
    • Type of data (e.g. number, text)
    • Check for valid values (e.g. domain)
  • Relationship classes
    • How objects are associated (e.g. 1:M, M:M)
    • Control feature behavior when edited (e.g. composite)

Source: (Zeiler, 2000)

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See GeoTech Center website (https://geotechcenter.org) �for additional Model Courses and other curriculum resources. �This Model Course Is Licensed Under Creative Commons CC BY-SA ����� By: https://creativecommons.org/licenses/by-sa/4.0/ ��Note: some content is a derivative of other CC authors���

Author: Wing Cheung

Title: Professor, Palomar College

Assistant Director, GeoTech Center

Email: wcheung@palomar.edu

​