Geodatabase Concepts Flashcards
3 Reasons to Group Features in A Geodatabase
- If a set of objects and features have relationships
- Features that have topological associations
- If you need to concurrently edit a set of features
3 Reasons to Separate Features into Different Geodatabases
- If different departments have responsibility over different datasets.
- Commercial relationship databases must be served through separate geodatabases.
- Personal geodatabases have size limits that may require partitioning data.
Attribute Tasks
Assign default attributes
Set up attribute domains
Declare attribute update policies for splitting & merging
Attribute Indexes
Indexes on one or several attributes in a table to make query performance faster.
Spatial Indexes
ArcInfo automatically creates on feature classes. It determines and applies an optimum grid size for you.
To optimize, you can define up to three grid sizes for best retrieval of data.
Polyline Feature Type
Has one or more paths. A path is a connected collection of segments, each of which can be a line, circular arc, elliptical arc, or Bezier curve.
Polylines can have an optional z (elevation) or m (measurement) value.
Null geometry
A specific feature in a feature class can have null geometry to represent objects that are sometimes represented as explicit features and sometimes as implicit features within composite objects.
Scale
Defines how many integers correspond to a map unit. If the scale is 1,000, then the maximum precision is 1/1,000 of a map unit.
Types of Attributes
Continuous Numeric (Floats & Doubles)
Discrete Numeric Values (Shorts & Integers)
Coded Values (Shorts, Integers, Text)
Description (Text)
Time Values (Dates)
Object Identifiers
Multimedia (BLOBs - Videos, Images, or Sound)
Subtype
A special attribute that lets you assign distinct simple behavior for different classifications of your objects or features. All subtypes share the same set of attributes.
Attribute Domains
Constraints on attributes including ranges, coded value domains, and default values
Validation Rules
Control feature and attribute integrity.Types include attribute rules, connectivity rules, relationship rules.
Connectivity Rules
Edge-Junction Rule
Edge-Edge Rule
Default Junction Type
Edge-Junction Cardinality
Attribute Relationship Rules
Constrains the cardinality between an origin class and a destination class.
One-to-one
One-to-many
Many-to-one
Many-to-many
You can create specialized cardinalities, like a state must have two senators.
Splitting Feature Rules
Default value applied to both.
Duplicate of the original feature.
Geometry ratio - the proportional value of the split areas or lengths.
Merging Feature Rules
Default value
Sum values - two numeric attributes are summed.
Weighted average of the original features’ attributes.
3 Relationship Rules
Topological, Spatial, General
Topological Relationships
Geometric Network or Planar Topology
Spatial Relationships
Determined by ArcInfo through common spatial operations.
General Relationships
Explicitly defined relationship cardinality controlled in a relationship class.
Simple relationship - peer-to-peer
Composite relationship - one-to-many
Notifications
A relationship class can be used to transmit notifications on edits & deletions to related objects.
Annotation Class
A feature class that contains annotation.
Feature-linked annotation: will add & remove annotation with editing based on values in attributes.
Simple annotation: not linked to feature.
Envelope
A geometry that describes the spatial range of feature geometries.
Polyline
An ordered collection of paths that can be disjoint or connected.
M-Values
A linear measure that can be assigned to each point in a point, multipoint, polyline, or polygon.
Top-Level Version in a Versioned Geodatabase is called?
Default
Optimistic Concurency
When no locks are applied to features when you start a long transaction.
Private Permission in a Versioned Geodatabase
Only the owner can view and edit data.
Protected Permission in a Versioned Geodatabase
All users can view, but only the owner can edit.
Public Permission in a Versioned Geodatabase
All users can view and edit.
Row State
Reflects all added, removed, and modified objects in a versioned geodatabase.
Precondition for Removing Versions
All their child versions must be removed first by reconciling or discarding.
Basic Versioning Operations
Editing, Reconciling your Edits, Posting Changes to the Parent Version
Two Reconciliation Conflicts
- The same feature has been updated in both the target version and the edit session.
- The same feature is updated in one version and deleted in the other.
What happens when you post a version to the target version?
The row state of your edit session synchronizes with the target version and they become identical.
Two-level Version Tree Workflow
Create a version for a project that is posted back when the project is complete.
Multilevel Version Tree Workflow
Each aspect of a project has its own version created, which can be posted back to the parent version and then posted to default when the project is complete.
Cyclical Version Workflow
Captures the project at each stage. When the last stage is completed, the version is posted to default.
Geometric Networks:
What is a logical network?
A pure network graph consisting of edges and junction elements, but no geometries. It consists of connectivity tables tracking the connections between features. It is always created with a geometric network and is edited behind the scenes.
Geometric Networks:
Nonplanarity
Edge features can cross in 2D space without intersecting.
Geometric Networks:
Network Feature Class
Represents a given topological role in a geometric network.
Geometric Networks:
List 4 Connectivity Rules
Edge-Junction Rule - Which types of junctions can connect to an edge.
Edge-Edge Rule - Which combinations of edge types can connect through a given junction.
Edge-Junction Cardinality
Default Junction Type
Geometric Networks:
Complex Edge Feature
A feature associated with any number of edges in a logical network. The edges must be arranged in a chain configuration.
Geometric Networks:
Complex Junction Feature
A collection of junctions and edges in a logical network. An internal network associated with features such as pump stations.
Geometric Networks:
List 3 features that configure flow direction.
Sources, Sinks, Switches
Geometric Networks:
Source
A junction from which a commodity flows.
Geometric Networks:
Sink
A junction where all commodity flow terminates
Geometric Networks:
Disabled Features
Do not participate in network flow: nothing flows into or out of the feature.
Geometric Networks:
Indeterminate Flow
When flow direction cannot be established for an edge.
Geometric Networks:
Uninitialized Flow
When a flow is isolated because the edges are disconnected from the rest of the network.
Geometric Networks:
Weights
Used to store the cost of traversing across an edge or through a junction. Typically the length of the edge. Weights are created from field values on the edge and junction feature classes.
Geometric Networks:
Solvers
A program that performs network analysis.
Geometric Networks:
NetFlags (List and Define)
Used to describe any location in a network.
EdgeFlags - include the % along the edge element.
JunctionFlags - exist on junctions.
Geometric Networks:
Barriers
Used by solvers to represent disabled logical network elements.
Geometric Networks:
Tracing
To follow the flow in a network until some condition is met.
Schema
The structure of a database or database object, such as a table. The schema defines the tables, fields, and relationships between fields and tables. Schemas are generally documented in a data dictionary.
Schematic Dataset
A schematic dataset contains a collection of schematic diagram templates and schematic feature classes that share the same application domain—for example, water or electrical. A schematic dataset also contains schematic diagrams that have been generated according to the rules and symbology set for their related schematic diagram template. These schematic diagrams can be organized and stored in schematic folders.
Schematic Diagram Template
A schematic diagram template holds the database and configuration properties defining the content and presentation of one or several schematic diagrams that will be generated. It holds the properties defining the representation of feature layers that compose the schematic diagrams and so behaves as the template for the display properties of specific schematic diagrams of a network.A schematic diagram template is assigned to one schematic dataset.
