Different types of GIS Data

1. TYPES OF GIS DATA
SUBMITTED BY:
PREETI PRAJAPATI

2. •Data defined as defined as
verifiable facts about the real
world.
•Information is data organised to
reveal patterns, and to facilitate
search.
•So the data collected is organised
primarily by attributes .
•A database is a collection of
inter-related data and everything
that is needed to maintain and use
it. A database management
system (DBMS) is a collection of
software for storing, editing and
retrieving data in database.
The coordinate location of a forestry stand would be
spatial data, while the characteristics of that forestry
stand, e.g. cover group, dominant species, crown
closure, height, etc., would be attribute data.
SPATIAL DATA:-
(Mapped data)
Spatial data is anything that
has
a geographical
location associated with it.
ATTRIBUTE DATA:-
(Tabular data)
Attribute data is
associated
information that is linked
to any of the spatial data.
GIS DATA TYPES
Also known as geospsatial data or geographic information, it is the
data or the information that identifies the geographic locations of
features and boundaries on Earth, such as :
•Natural or constructed features,
•Oceans and more.
 Spatial data is usually stored as coordinates and topology,
and is data that can be mapped, i.e. in a geographic file.
Spatial data is often accessed, manipulated or analyzed
through Geographic Information Systems (GIS).

3. Raster Data :
 In the raster data model, land
cover is represented as:
 single square cells.
 Each cell will have a value
corresponding to its land cover
type.
 Data are divided into cell, pixels,
or elements
 Cells are organized in arrays
having single value
 Row and Column Numbers are
used to identify the location of
the cell within the array.
 The most common example of
raster data is a digital image.
Vector Data:
In the vector data model, features on
the earth
are represented as :
points
lines / routes
polygons / regions
TINs (triangulated irregular
networks)
Vector data are good at :
•accurately representing true shape
and size
•representing non-continuous data
(e.g., rivers, political boundaries,
road lines, mountain peaks)
•creating aesthetically pleasing maps

4. VECTOR RASTER
ADVANTAGES •Efficient Representation Of Topology
•Adapts Well To Scale Changes
•Allows Representing Networks
•Allows Easy Association With Attribute Data
•Simple Data Structure
•Simple Implementation Of Overlays
•Efficient For Image Processing
DISADVANTAGE
S
•Complex Data Structure
•Overlay More Difficult To Implement
•Inefficient For Image Processing
•More Update-intensive
•Less Compact Data Structure
•Difficulties In Representing Topology
•Cell Boundaries Independent Of Feature
Boundaries.

5. GIS systems traditionally maintain spatial
and attribute data separately, then
“join”them for display or analysis for
example, in ArcView, the Attributes of …
table is used to link a shapefile (spatial
structure) with a data base table containing
attribute information in order to display the
attribute data spatially on a map.
 Tabular or textual data describing the geographic characteristics of features.
 Charts that use attributes data include bar chart, pie chart, Pareto chart, and
some types of control chart.
For example- the spatial data might represent a county and contain information
for city boundaries, census tract boundaries, streets, and so forth. An attribute data
set with population information for each census tract can be linked to a map by the
corresponding tract value in the spatial data.
ATTRIBUTE DATA
 Attribute (descriptive) data (what, how much, when) :
 specifies characteristics at that location, natural or human-created
 stored in a data base table

6. GIS DATA
ELEMENTSPOINT (No Dimensions)
• Points DO NOT have
length, width or area
• Represented as
COORDINATE PAIR
• Used to represent
DISCRETE
LOCATIONAL
INFORMATION on the
map to identify
locations of features
such as cities, towns,
well locations, rain
gauge stations, soil
sampling points, etc.
POLYGON (Two
Dimensions)
• Set of ordered
COORDINATES
• Represented by a STRING
OF COORDINATES.
• It has length, but no width or
area.
• Used to represent roads,
streams or canals which
have too narrow a width to
be displayed on the map at
its specified scale.
• Lines that directly connect
two nodes are sometimes
referred to as chains,
edges, segments, or arcs.
LINE (One Dimension)
• CLOSED FEATURE
whose boundary encloses
a homogeneous area
• Represented by a
CLOSED STRING OF CO-
ORDINATES which
encompass an area.
• Used to represent area
features such as forest
stands, soil classification
areas, administrative
boundaries, and climate
zones, etc.

7. Points are
stored as
individual COL,
ROW entries in
a matrix.
Areas are
stored as a set
of contiguous
cells defining
the interior.
Lines are
stored as a set
of connected
cells.
Points are
identified as
individual X, Y
coordinates.
Area is
identified as a
set of
connected
coordinates
defining the
boundary.
Lines are a
connected set
of points.