INTRODUCTION TO THE GEOGRAPHIC INFORMATION … · The shape of a geographic object may be a point, a line or a polygon. Each object has a geographiclocation which can be expressed

University of Foggia

STAR*AgroEnergy Research Group

IP Erasmus Equi – Agry, Foggia , 7th July 2014

INTRODUCTION TO THE

GEOGRAPHIC INFORMATION SYSTEM

(GIS)

Anna Rita Cammerino

- General information- Geographic data

- Data models

- Cartographic representation- The concept of scale

- GIS softwares- Spatial analysis

- How to organize a GIS project

- Examples

OUTLINE

FIRST PART 9-11

SECOND PART 11-13

- exercises

Geographic Information System - GIS

G Geographic: data are georeferred

I Information:

Geographic objects (feature)

Attributes (qualitative, quantitative)

S System: different components

GENERAL INFORMATION

General information - Geographic data - Data model - Cartographic representation - The concept of

scale - GIS software - Spatial analysis - How to organize a GIS project - Examples

Geographic Information System components



GENERAL INFORMATION

Assessment, monitoring and management of the land

The main objective of GIS is to create thematic maps to

Catch

analyzesolve

critical situations related to

EnvironmentalSocial

Economic

Demographic

ISSUES

TransportationAgricultural



GENERAL INFORMATION

In which field is it possible to apply GIS?

Environmental monitoring

Urban planning

Water resources management

Remote sensing

Geomarketing

Risk analisys (sismic, volcanic, flood)

Traffic management plan

Private companies

Public institutions



GENERAL INFORMATION

Detailed answers to precise questions:

- where are the cities with more than 200.000 inhabitants in a certain region?

- how many wells are located within a distance of 200 meters from a water body?

- calculate the slope of a certain area.

- calculate the area and the perimeter of a certain parcel land.

- calculate the best route from point A to point B according to the road

network.

- highlight the plant species that are within certain altitude ranges in a forest map.



GENERAL INFORMATION

Social factorsSocial factors

Forests Forests

Road networkRoad network

Land useLand use

A layer is a set of

geographic objects calledfeature.



GEOGRAPHIC DATA

Open source softwares

- GRASS, GIS (Geographic Resources Analysis Support System) distributed byGNU General Public License (GPL), (http://grass.osgeo.org).

- MapWindow GIS, developed by EPA (United States EnvironmentalProtection Agency), Mozilla Public License in .NET(http://www.mapwindow.org)

- Quantum GIS (QGIS) (http://qgis.org)

General information- Geographic data - Data model - Cartographic representation - The concept of


GIS SOFTWARE

Software with license:

ArcGis: www.esri.com

Geomedia: www.intergraph.com

IDRISI: http://www.clarklabs.org/



GIS SOFTWARE



GIS SOFTWARE

ArcGis desktop versions



GIS SOFTWARE

Modules:

- ArcMap

- ArcToolbox

- ArcCatalog

- ArcScene

- ArcGlobe


scale - GIS software - How to organize a GIS project - Spatial analysis - Examples

GIS SOFTWARE



GEOGRAPHIC DATA

Each feature is characterized by:

- Shape

- Location

- Symbols

- Attributes

The shape of a geographicobject may be a point, a line or

a polygon.

Each object has a geographic location which can be expressed with

the values of latitude and longitude.

Each object can be represented by a symbol.

Each geographic object has attributes that are information

describing the object.



GEOGRAPHIC DATA

The features of a layer are of the same geometry type (point, line, or polygon) and have the same set of attributes.

DATA MODEL: VECTOR and RASTER

Vector data are point, line, polygon.

They are useful to store and represent discrete objects such asbuildings, roads, land parcels, lakes.

The data are stored as a list of coordinates:

Points: pair of coordinates

Lines: ordered set of coordinates

Polygons: ordered set of coordinates that define the perimeter of the figure.



DATA MODEL

Rasters are not defined by

the coordinates but are described by pixels whose

size determines the resolution.

Raster data: set of cells - pixels - arranged in rows and columns;

used to store continuos data such as altitude, slopes, temperature…



DATA MODEL

General concept

The issue of determining the shape of the Earth's surface and the representation of its parts on a flat paper has encouraged the development of various disciplines.

Geodesy: the science that deals with the determination of the shape and size of the physical surface of the Earth.

Topography: examines the tools, the survey techniques, the calculations necessaryto reflect the surface of the Earth on a map.

In both cases, it is important to have a reference surface.



CARTOGRAPHIC REPRESENTATION



CARTOGRAPHIC REPRESENTATION

Reference surfaces

Geoid

Ellipsoid

The distance between two points on a map is given by the ratio between the distance on the map and the distance on the earth's surface.

Es.:

If a street long 5 kms is represented by 1 cm on the map, it means that:

1cm:500.000cm

1:500.000

The smaller the denominator greater the scale

Large scale greater details Small-scale minor details

1:5.000 1:100.000

In a GIS software, the scale is dynamic. It is possible to zoom in and out tochange the scale.

.General information- Geographic data - Data model - Cartographic representation - The concept of


THE CONCEPT OF SCALE

Main spatial analysis functions:

Select by attribute



SPATIAL ANALYSIS

Buffer



SPATIAL ANALYSIS

Main spatial analisys functions:

Overlay



SPATIAL ANALYSIS


Map algebra



SPATIAL ANALYSIS




HOW TO ORGANIZE A GIS PROJECT

A GIS project must follow the following four steps:

- definition of the objectives;

- database creation;

- data analysis;

- presentation of the results.

Definition of the objectives

Database creation

- what is the problem?

- is it possible to solve it by using GIS or are there any alternative

methods?- what are the main results we expect?

- who is interested in these results?

- identify the right spatial data useful to solve the problem- performing quality check on data

- identify the alphanumeric attributes to be associated to the spatialdata and arrange the tables

- organize the thematic layers




Data analysis




Give detailed answers to precise questions

Presentation of the results

Maps that can be associated with tables, graphs, 3D

representation…

1. Calculate the population density of the provinces belonging to

Apulia region.2. Select the highway A14 and extract the segment belonging to

Foggia province.3. Create a land use map

4. Find caves within a distance of 15 km from the A14 segment

located in Foggia province.

EXERCISES

Thank you for your attention!

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Documents

INTRODUCTION TO THE GEOGRAPHIC INFORMATION … · The shape of a geographic object may be a point, a line or a polygon. Each object has a geographiclocation which can be expressed