SGG 2443

PRI NCI PLES OF GEOGRAPHI C I NFORMATI ON SCI ENCE

LECTURE 4 – SUBSYSTEMS I N GI S

Assoc Prof Mohamad Nor Saidm.nor@utm.my

Lecture Outline:

• I ntroduction• Subsystem For Data I nput • Subsystem For Data Storage &

Management• Subsystem For Data

Manipulation & Analysis• Subsystem For Data Output

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

ArcView

Data InputData Storage

&

Management

Data

Display

(Output)

Data

Manipulation

& Analysis

GIS - 4 SUBSYSTEMS

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Subsystem For Data Input

• raw data is converted into digital

• data: spatial & non-spatial (attribute)

• requires correction; verification; updating

• spatial data entry is more critical

– quality; cost; time; availability

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Manual Digitizing

• records map coordinates in digital

format

• data recorder (device) – digitizer

• now: head-up (on-screen) digitizing

• object: point; line; polygon

• mode: point; stream

Field Surveying

• field data recorder: e.g. Total Station

• observation: distance; bearing;

vertical angle

• data: coordinates; elevation

• digital file: import into GIS

Subsystem For Data Input (cont’d.)

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Photogrammetry

• uses aerial photographs

• maps produced from stereomodel

(2 overlapping photos)

• requires geometric correction

(rectification)

• mosaic (stitched photos) = orthophoto

• now: digital photogrammetry

Remote Sensing

• data from satellite images

• every single object reflects different

frequencies

• image classified digitally

• correction: radiometric & geometric

• format: raster; vector conversion

• image interpretation: done digitally

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Subsystem For Data Input (cont’d.)

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Subsystem For Data Input (cont’d.)Photogrammetric Mapping

Subsystem For Data Input – Remote Sensing

Remote Sensing Satellite

Solar PanelSensor

Ground surface being scanned

Remote Sensing Image

Image :

a) Panchromatic

b) Color:

• True color

• False color

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Earth observation satellites usually follow the sun synchronous orbits.

A sun synchronous orbit is a near polar orbit whose altitude is such that the satellite

will always pass over a location at a given latitude at the same local solar time.

In this way, the same solar illumination condition (except for seasonal variation) can

be achieved for the images of a given location taken by the satellite.

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Subsystem For Data Input – Remote Sensing

Landsat 4,5 (USA)

• Sun-synchronous

• optical/ infra red

• 705 Km altitude

• 16 days repeat cycle

• resolution

– Multi Spectral Scanner (MSS) 80m

– Thematic Mapper (TM) 30m

– Thermal Infra Red 120m

• ground swath 185Km

SPOT (France)

• Sun-synchronous

• optical/ infra red

• 832 Km altitude

• 26 days repeat cycle

• resolution

– Panchromatic 10m

– Multispectral 20m

• ground swath 60Km

IRS (India)

• Sun-synchronous

• optical/ infra red

• 817 Km altitude

• 24 days repeat cycle

• resolution

– Panchromatic 10m

– Multispectral 23m

• ground swath 140Km

LECTURE 4: GI S SUBSYSTEMS

SGG 2443 - Principles of Geographic Information Science

Subsystem For Data Input – Remote Sensing