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Functions of GIS
Major Functions of GIS
1. Data Capture
• Data used in GIS often come from many different sources, are of many
types, and are stored in different ways.
• GIS provides tools and a method for the integration of different data
into a format to be compared and analysed.
• Data sources are mainly manual digitization/scanning of aerial
photographs, paper maps, and existing digital datasets. Remote-sensing
satellite imagery and GPS are promising data input sources for GIS.
Major Functions of GIS
2.Database Management and Update
• After data are collected and integrated, the GIS must provide
facilities which can contain and maintain data.
• Effective data management has many definitions but should include
all of the following aspects:
– data security
– data integrity
– data storage
– retrieval, and
– data maintenance abilities.
Major Functions of GIS
3. Geographic Analysis
• Data integration and conversion are only a part of the input phase of
GIS. What is required next is the ability to interpret and to analyse the
collected information quantitatively and qualitatively.
For example, a satellite image can assist an agricultural scientist to
project crop yield per hectare for a particular region. For the same
region, the scientist also has the rainfall data for the past six months
collected through weather station observations. The scientist also has a
map of the soils for the region which shows fertility and suitability for
agriculture. These point data can be interpolated and what you get is a
thematic map showing iso-heights or contour lines of rainfall.
Major Functions of GIS
4.Presenting Results
• One of the most exciting aspects of GIS technology is the variety of
different ways in which the information can be presented once it has been
processed by GIS.
• Traditional methods of tabulating and graphing data can be supplemented
by maps and three dimensional images.
• Visual communication is one of the most fascinating aspects of GIS
technology and is available in a diverse range of output options.
Adapted from J.Stars and J.Estates
Data Recording Form
Field Map
Deep water table
Shallow water table
July, 1999
June, 2000
Ucchali Lake, Salt Range
S n ow Le op ard
R iv ers
P a n th e ra u n c ia
G ru_ gru (C o m m on C ran e)
P a k is tan B oun da ry
S n ow Le op ard
R iv ers
P a n th e ra u n c ia
A n t_v ir (D e m o is elle C ra ne )
P a k is tan B oun da ry
D is trib u tio n Crane
M ap
S n ow Le op ard
R iv ers
P a n th e ra u n c ia
G ru_ le u (S ibe rian C ran e)
P a k is tan B oun da ry
C om m o n C ra ne
G ru s g ru s
M igran t
D is trib u tio n M aCrane
M a jo r R iv ers
P a kis tan B oun da ry
D em oise lle C ran e
A n th ro p o id e s v irg o
M igran t
D is trib u tio nCrane
M ap
M a jo r R iv ers
P a kis tan B oun da ry
S ibe rian C ra ne
G ru s le u c o g e ra n u s
M igran t
M a jo r R iv ers
P a kis tan B oun da ry
Indus Flyway
One way of understanding GIS is to look at
the problems it can solve…
Questions a GIS can answer
• There are five types of question that a sophisticated GIS can
1 Location:What is at...?
– To find what exists at a particular location
– A location can be described in many ways;
• place name,
• post code, or
• geographic reference such as longitude/latitude or x and y
Questions a GIS can answer
2 Condition: Where is it...?
– Find location(s) where certain conditions are satisfied
– e.g., non-forested section of at least 2,000 square metres in
size, within 100 metres of a road, and with soils suitable for
supporting buildings
3 Trends: What has changed since...?
– To find the differences within an area over time
– e.g., changes in land use of a block of land over the last 10 years
Questions a GIS can answer
4 Patterns: What spatial pattern exists...?
– E.g., landslides are mostly occurring where;
• slopes are high,
• soil is not stable and
• vegetation is low
Questions a GIS can answer
5 Modelling: What if...?
– What if a toxic substance seeps into the local groundwater
– Use GIS to calculate how far it will spread, how quickly, the
level of toxins at a given location, etc.
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