GIS

1. The
GIS
Database
Chapter
7,8
&
9
1
The
backbone
of
GIS
is
good
data
accurate
enough
to
accomplish
its
objectives.
Geographic
data
are
organized
in
a
geographic
database.
There
are
two
important
components
of
this
geographic
database:
geographic
position
(spatial
data)-where
is
it?
attributesor
properties(attributedata)-what
things
are?
GIS
data
types
of
are
grouped
into
three
classes:
i.
Spatial
data
(where?):
used
to
describe
location,
shape,
size,
and
all
kinds
features
of
spatial
entities.
GIS
Data
Concepts

2. ii.
Non-spatial
data
(what,
when,
in
what
amount?):
also
called
attribute
or
characteristic
data,
Also
known
as
descriptive
data
There
are
fundamental
differences
between
them:
spatial
data
are
generally
multi-dimensional
and
autocorrelated.
iii.
Metadata:
is
data
about
data
and
contains
information
about
scale,
accuracy,
projection/datum,
data
source,
manipulations,
how
to
acquire
data.

5. iv.
Area
(polygon)
Used
to
represent
two
dimensional
features.
Polygonal
features,
such
as
city
boundaries
and
river
catchments
can
be
stored
as
a
closed
loop
of
coordinates.
Polygonal
data
is
the
most
common
type
of
data
in
natural
resource
applications.
Examples
of
polygonal
data
include
forest
stands,
soil
classification
areas,
administrative
boundaries,
and
climate
zones.
Vector
Representations
(Contd..,)
Raster
Model
Vector
Model
Advantages:
Simple
data
structure
Easy
and
efficient
overlaying
Compatible
with
RS
imagery
High
spatial
variability
is
efficiently
represented
Simple
for
own
programming
Disadvantages:
Need
high
computer
storage
Errors
in
perimeter
and
shape
Difficult
network
analysis
Inefficient
in
projection
transformations
Loss
of
information
when
using
large
cells
Advantages:
Compact
data
structure
Efficient
for
network
analysis
Efficient
for
projection
transformation
Accurate
map
output.
Disadvantages:
Complex
data
structure
Difficult
overlay
operations
High
spatial
variability
is
inefficiently
represented
Not
compatible
with
RS
imagery
Raster
vs
Vector
(Contd..,)

6. Database
Definitions
What
is
a
database?
based
system.
What
is
a
database
management
system
(DBMS)?
A
software
system
designed
to:
Organize
that
data
in
a
flexible
manner,
Provide
tools
to
add,
modify
or
delete
data
from
the
database,
Query
the
data,
Produce
reports
summarizing
selected
contents.
11
A
database
can
be
defined
as:
A
collection
of
related
data/information
stored
in
a
structured
format.
Computerized
collection
of
structured
data
stored
in
one
or
more
tables
as
electronic
filing
cabinet.
A
collection
of
inter-related
data
stored
together
to
serve
one
or
more
applications.
A
combination
of
software
and
hardware
that
makes
it
possible
and
convenient
to
perform
tasks
that
involve
handling
large
amounts
of
data.
The
data
are
stored
together
with
as
little
redundancy
as
possible
to
serve
one
or
more
users.
Database

7. What
is
the
ultimate
purpose
of
a
database
management
system?
Data
Information
Knowledge
Action
Is
to
transform
13
Features
of
a
DBMS
Database
Management
Systems
provide
features
to
maintain
database:
Transaction
management
-
A
transaction
comprises
a
unit
of
work
performed
within
a
DBMS
against
a
database,
and
treated
in
a
coherent
and
reliable
way
independent
of
other
transactions.
Transactions
in
a
database
environment
have
two
main
purposes:
To
provide
isolation
from
other
transactions.
Transactions
must
pass
the
ACID
test
(atomic,
consistent,
isolated
and
durable
14

8. Features
of
a
DBMS
Database
Management
Systems
provide
features
to
maintain
database:
Concurrency
control
-
ensures
that
correct
results
for
concurrent
operations
are
generated,
while
getting
those
results
as
quickly
as
possible.
Backup
and
recovery
Provides
a
language
for
the
creation
and
querying
of
the
database.
A
language
for
writing
application
programs
Lecture
8
15
DATA
BASE
MANAGEMENT
SYSTEM:
Dale
and
McLaughlin
(1988)
define
a
DBMS
as
a
computer
program
to
control
the
storage,
retrieval
and
modification
of
data
(in
a
database)
Stern
and
Stern
(1993),
a
DBMS
will
allow
users
to
joint,
manipulate
or
otherwise
access
the
data
in
any
number
of
database
files.

9. Spatial
database
is
a
collection
of
spatially
referenced
data
that
acts
as
a
model
of
reality.
To
create
and
maintain
a
computer
database,
you
need
a
database
program,
often
called:
DBMS
is
a
software
package
that
allows
the
user
to
set
up,
create
and
maintain
a
database.
GIS
is
a
DBMS
specifically
designed
for
processing
of
spatial
and
related
attribute
data.

10. Handling
large
amounts
of
data.
Backup
and
recovery
functions
to
avoid
loss
of
data.
Declarative
query
language
for
retrieval
of
data.
Collecting
all
data
at
a
single
location
reduces
duplication.
redundancy
and
Maintenance
costs
decrease
because
of
better
organization
and
decreased
data
duplication.
Applications
become
data
independent
so
that
multiple
applications
can
use
the
same
data.
User
knowledge
can
be
transferred
between
applications
more
easily
because
the
database
remains
constant.
Data
sharing
is
facilitated
and
a
corporate
view
of
data
can
be
provided
to
all
managers
and
users.
Security
and
standards
for
data
and
data
access
can
be
established
and
enforced.
Why
Use
a
Database?
Selecting
a
Database
Management
System
Database
management
systems
(or
DBMSs)
can
be
divided
into
two
categories:
Desktop
databases
are
oriented
toward
single-user
applications
and
reside
on
standard
personal
computers
(hence
the
term
desktop).
Server
databases
contain
mechanisms
to
ensure
the
reliability
and
consistency
of
data
and
are
geared
toward
multi-user
applications.
Lecture
8
20