The document discusses vector data models and composite feature representation in GIS. It covers the following key points: 1. The object-based data model represents geospatial data as objects that have both geometry and attribute properties. This allows spatial and non-spatial data to be stored together. 2. Composite features like TINs, regions, and routes combine basic geometric shapes into higher-level representations. TINs model terrain, regions divide areas by characteristics, and routes are linear features with measurement systems. 3. The geodatabase is a vector data model that uses an object-oriented approach. It has advantages like topological rules and customization capabilities but also challenges like complexity, software dependence, and performance

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3. Topic: Vector Data Model
Object Based Data Model
 Classes and class Relationships
 Interface
 The Geodatabase
 Topology rules
 Advantages of the Geodatabase
Representation of Composite Features
 TINs
 Regions
 Routes

4. The term "Object-based data model" refers to a data model that is based on
object-oriented programming principles and concepts. In this data model, data
is represented and organized as objects, similar to how objects are used in
object-oriented programming languages. Each object consists of data attributes
(properties) and associated behaviors (methods).
In the context of GIS (Geographic Information Systems), the object-based data
model represents geospatial data as objects. These objects can represent
various spatial features such , or any other geographic
entity. The object-based data model allows for the storage and manipulation of
both the geometry (spatial information) and attributes (non-spatial
information) of these objects within a single system

5. Here shows the object oriented data model that represented as a object.

6.  Characteristics Of Object base data model
1. The object-based data model stores geometries and attributes in a single
system . Geometries are stored as a collection of binary data in a special field
with the data type BLOB (binary large object).
Object id Shape Land use ID Category Shape Length Shape-Area
1 Polygon 1 5 14,607.7 5,959,800
2 Polygon 2 8 16,979.3 5,421,216
3 Polygon 3 5 42,654.2 21,021,728
There are two main characteristic of object base data mode which are
The Table shows object-based data model stores each land-use polygon in a
record. The Shape field stores the geometries of land-use polygons. Other
fields store attribute data such as Land use_ID and Category.

7. 2. The object based data model allows a spatial feature (object) to be
associated with a set of properties and methods.
 A property describes an attribute or characteristic of an object.
We can example like that,
As a feature layer object, a road layer can have the properties of
shape and extent and can also have the methods of copy and
delete. Properties and methods directly impact how GIS operations
are performed.
 A method performs a specific action.

8. In object-oriented technology, there are several types
of class relationships that facilitate the management
of objects in GIS. These are
 Association
 Aggregation
 Composition
 Type inheritance and
 Instantiation
Association: A relationship between two classes, defining how instances of one
class can be connected to instances of another class.
An example: A "Person" class associated with an "Address" class, where a person
can have one or more addresses.
Aggregation: It should be Combining at least two or more classes into a single one
class that is called aggregation.
An example: A census tract is an aggregate of a number of census blocks.
What are the different types of Classes and Class Relationships?
Fig: Data Aggregation

9.  Composition: A stronger whole-part relationship, where the component
class is an essential part of the composite class and cannot exist
independently.
For example: A "House" class composed of multiple "Room" objects.
 Instantiation: The creation of an object or instance of a class based on its
definition.
Example: Creating a "Student" object from a "Person" class, representing a
specific student with unique attributes and behaviors.
 Type Inheritance: A hierarchical relationship between a superclass and
one or more subclasses, where subclasses inherit properties and methods
from the superclass.
Example: A "Shape" superclass with subclasses like "Circle," "Rectangle," and
"Triangle" inheriting common attributes.

10.  What is Interface ?
An interface represents a set of externally visible operations of a class or
object. Object-based technology uses a mechanism called encapsulation to
hide the properties and methods of an object so that the object can be
accessed only through the predefined interfaces.
(In Fig: 2) A Feature object implements the
IFeature interface.
IFeature has access to the properties of
Extent and
Shape and the method of Delete. Object-
oriented technology
uses symbols to represent interface,
property
and method.

11.  External Visibility
Encapsulation
Contractual Agreement
 Access through Interfaces
 Object-Based Technology
The major characteristics of an interface_

12. The geodatabase is an object-based vector
data model that is part of ArcObjects, the
foundation for ArcGIS for Desktop. ArcObjects
consists of numerous objects and classes that
are accessed through menus, icons, and
dialogs developed by Esri. The geodatabase
uses points, polylines and polygons to
represent vector-based spatial features.
Fig: 3
What are the different types of geodatabases ?
There are three types of geodatabases which are
 Personal geodatabase
 file geodatabase and
 multiuser (ArcSDE) geodatabase.
What is Geodatabase and how does it relate to ArcObject?

13. The Geodatabase organizes vector data sets into two types:
 A feature class stores spatial features of
the same geometry type.
 A feature dataset stores feature classes
that share coordinate system and area
extent.
 For example, a feature class maybe
represent block groups and a feature
dataset may consist of block groups,
census tracts and countries for the same
study area.
Fig: 4

14. Topology rules are predefined constraints that govern the spatial relationships
and connectivity of features in a geodatabase. They ensure data integrity and
maintain consistent geometric relationships between features.
These rules define requirements such as connectivity, overlap prevention,
boundary coincidence, feature orientation, and relationship validation. They
play a crucial role in managing spatial data accuracy and reliability.
What is Topology Rules ?
 Topological or topology base data are useful for detecting and correcting
digitizing error in graphic data set and are necessary for some GIS analyses.
 Topological data structures help to ensure that information is not
unnecessarily represented.
The database stores one line only in order to represent a boundary.

15. Topology is often explained through graph theory. It has mainly two
advantage

16.  Counties must not overlap.
 County must not have gaps.
 County boundary must not have dangles Census tracts and counties must
cover each
 Voting district must be covered by county.
 Contour lines must not intersect.
 Interstate route must be covered by feature
class of reference line (i.e., road feature class).
 Milepost markers must be covered by reference
line (i.e., road feature class).
Gap

17. Topology Rules in the Geodatabase
Feature Type Rules
1. Point
Must be coincident with, must be disjoint, must be covered by
boundary of, must be properly inside polygons, must be
covered by end point of, and must be covered by line.
2. Line
Must be larger than cluster tolerance, avoid overlap,
intersection, dangles, pseudo-nodes, touch interior, overlap, be
covered by feature class, boundary, inside, end point, self-
overlap, self-intersect, and single part.
3. Polygon
Cluster tolerance is crucial for coverage, avoiding overlap, gaps,
and overlapping features. Boundaries must be covered, and
points must be present.

18. Overview Topology Rule

19. What are the advantages of the Geodatabase ?
The geodatabase offers several advantages compared to other data
models:
 Hierarchical structure
 Object-Oriented Technology
 On-the-Fly Topology
 Customization and Application Development
 Industry-Specific Data Models
 Hierarchical structure: The geodatabase can be organized into a
hierarchical structure of feature datasets, feature classes, and
attributes. This makes it easier to manage large and complex datasets.
 Object-oriented technology: The geodatabase uses object-oriented
technology, which allows for more complex and sophisticated data
modeling.

20.  On-the-fly topology: The geodatabase supports on-the-fly topology, which
ensures that the spatial relationships between features are always correct.
 Customization: The geodatabase can be customized to meet the specific
needs of users.
 Industry-specific data models: The geodatabase includes a number of
industry-specific data models, which can be used to store and manage data
for different applications.
What are the disadvantages of the Geodatabase ?
There are some disadvantages of geodatabase which are
 Complexity
 Software Dependency
 Storage Size and Performance
 Costing

21.  Complexity: Geodata bases can be complex to learn and use, especially
for users who are not familiar with database concepts.
 Software dependency: Geodata bases are only supported by Esri
software, so users who want to use them must have access to this
software.
 Storage Size and Performance: Geodata bases can be large,
especially if they contain a lot of data. This can make them difficult to share
and transfer.
 Performance: Geodata bases can be slow to perform certain
operations, such as spatial queries. This is because they need to access and
process data from multiple tables and indexes.
 Costing: Geodata bases can be expensive to set up and maintain. This is
because they require specialized software and hardware

22. Representation of Composite Features
 What is Composite features ?
A composite feature refers to a spatial feature that is composed of
multiple simpler geometric elements. It is a higher-level representation
that combines multiple basic geometric shapes or entities into a single
feature.
Composite Features
1.TINs
2.Regions
3.Routes
What are types of Composite features ?
Composite feature are mainly three types:

23. TINs
Triangulated irregular networks (TIN) are a digital means to represent surface
morphology. TINs are a form of vector-based digital geographic data and are
constructed by triangulating a set of vertices (points).
It is commonly used for terrain mapping and analysis, especially for 3-D display
Fig: 5, Each triangle is a polygon, each node of a triangle is a point, and each
edges of a triangle is a line
 Each triangle in the TIN assumes a constant gradient. Flat areas of the land
surface have fewer but larger triangles, whereas areas with higher variability in
elevation have denser but smaller triangles.

24.  Data structure of TINs
A TIN should be comprised three
types of geometric objects
1. Points (nodes)
2. Lines (edges)
3. Polygons (triangle )
It’s data structure showing that the lists of points, edges, as well as the x, y, and z
values of each elevation point.
Here, Z value is most important element of TIN model. It help to better
understanding the shape of the land and the relationships between different
features as well as calculating slopes ,aspect and determining the suitability.

25. Fig: LiDAR data
Fig: Digital Elevation Model
Fig: Aerial photography
Fig: GPS Survey

26. Terrain Mapping
Fig : Hill shading
.
 There many methods for terrain mapping. Some common terrain mapping
techniques are presented here.
 Contouring
 Vertical profiling
 Hill shading
 and Perspective view
Fig : Contouring

27. The application of TINs :
There are several uses in the field of geospatial analysis and visualization
which are
1. Terrain Mapping: TINs are frequently employed to create accurate
representations of the Earth's surface, capturing elevation variations and
features such as hills, valleys, and mountains.
2. Surface Analysis: TINs enable various types of surface analysis, such as
slope analysis, aspect analysis, and visibility analysis. These analyses
provide valuable insights for fields like hydrology, urban planning, and
environmental modeling.
3. 3D Visualization: TINs serve as a basis for generating 3D visualizations
of terrains. They allow for realistic rendering and simulation of landscapes
4. Hydrological Modeling: Like that watersheds and drainage patterns .

28. Characteristics of TINs:
 Adaptive Resolution: TINs provide adaptive resolution, meaning they can adjust
the density of triangles based on the variability of the terrain. This adaptability
ensures efficient representation of terrain features.
 Non-overlapping Triangles: Each triangle in a TIN is non-overlapping, ensuring
that there is no duplication or overlap of terrain information. This characteristic
maintains the accuracy and integrity of the representation.
 Constant Gradient: Within each triangle, a TIN assumes a constant gradient.
This assumption simplifies the representation of the terrain, allowing for
straightforward calculations and analysis of slope, aspect, and other surface
properties.
 Incorporation of Features: TINs can incorporate various types of features, such
as elevation points, contour lines, streams, roads, and polygons like lakes and
reservoirs. These additional features enhance the accuracy and detail of the TIN
representation.

29. Region
Fig:6
 In the context of Representation of
Composite Features, a region refers to
a geographic area that exhibits similar
characteristics. It is a way of dividing
the Earth's surface into smaller
uniform areas.
 Regions can be hierarchical, meaning they can be subdivided into smaller
regions within a larger region. Examples of hierarchical regions include
census units, hydrologic units, and ecological units
 A region is a geographic area with
similar characteristics (Bailey 1983;
Cleland et al. 1997).

30. Real-world applications of regions:
 Urban Planning: Regions can be used to define zoning districts or planning
regions for land-use management, transportation planning, and
infrastructure development.
 Environmental Management: Regions can help define ecological regions or
biomes, which aid in conservation efforts, biodiversity assessment, and
ecosystem management.
 Market Analysis: Regions are often used in market research to identify and
target specific consumer segments based on demographic, economic, or
cultural similarities within a given area.
 Resource allocation: Regions can assist in the allocation of resources such
as healthcare facilities, schools, or emergency services, ensuring equitable
distribution based on population density or specific needs.

31. Route
A route is a linear feature such as a highway, a bike path, or a stream, but
unlike other linear features, a route has a measurement system that allows
linear measures to be used on a projected coordinate system .
Fig: 7, The data structure of a route subclass

32. Route
A route is a linear feature such as a highway, a bike path, or a stream, but
unlike other linear features, a route has a measurement system that allows
linear measures to be used on a projected coordinate system .
A B
D
C E
F
Polyline
Route
Fig: 7

33. Importance of Route:
There are many importance of route which are -
Association of
Events
Transportation
Planning
Natural
Resource
Management
Polylines and
Geodatabase

34. Association of Events:
Routes enable event association with linear features like accidents, bridges,
pavement, water quality, and fishery conditions, enabling comprehensive
analysis and visualization of relationships between events and routes.
Transportation Planning:
Routes are vital for transportation planning and management, locating
accidents, bridges, and pavement conditions, optimizing networks, and
determining efficient public transportation routes.
 Natural Resource Management:
Natural resource agencies utilize routes to record and analyze data on water
quality, fisheries, and ecological conditions, enabling effective management and
conservation by identifying linear measures.
Polylines and Geodatabase :
Routes in GIS applications represent polylines with measure values in
geodatabased simplifying analysis and management. They enable spatial
integration and visualization by associating events and attributes with routes,
enhancing understanding of patterns, connectivity and relationships.

35.  What do you means Interface ?
 What is Geodatabase and how does it relate to ArcObject ?
 Describe the advantage and disadvantages of Geodatabase.
 What is Topology rules and Why Topology ?
 Discuss the
 What do you means TINs and how to represented it ?
 Write the data structure of TINs and why Z values is most important
to representation Tins ?
 Write the data sources of TINs and describe the application of Tin.

36. THANK you