Tutorial ArcGIS Introduction PART 1

CONTENTS

CHAPTER1: Introduction

CHAPTER2 : Manage Catalog of data

CHAPTER3 : Show data

CHAPTER4 : Update data

CHAPTER5 : Working with tables

CHAPTER6: Manipulate data georeferenced

CHAPTER7: Query data

CHAPTER8: Present data

Chapter 1: Introduction part 1 getting to know ArcGIS desktop

Tutorial  ArcGIS Introduction PART 1

Defining a Geographic Information System

What is GIS?
5 major components: Equipment/Users/Software/Data/Methods

Definition:

There are many definitions of a Geographic Information System (GIS). Very simply, a GIS is a computer tool that allows to integrate, locate, analyze and represent data Who has or not a geographic dimension.
To function, it is necessary to involve all of the following:

• People: This is the most important element in a GIS. Individuals must define treatments and develop operating procedures.

•  The availability and accuracy of data: they condition opportunities for interrogation And analysis.

• Hardware: the hardware capabilities condition the operating speed, ease Of use and type of possible release.

• Software: by this is meant GIS, but also the databases of software, drawing, Statistics, imaging, or specific applications.

• Information handling procedures: the establishment of a GIS involves the application of certain rules and procedures.

Features

The combination of all these elements provides the following basic functions:

•  The capture, storage, and data management.
•  The processing, analysis, selection, and display of data.
•  The production of maps, reports, tables, and other information syntheses.

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The different data formats

Geographical data

The geographical information includes two types of data:

Spatial data
Geometry and location of the object

Attribute data
Descriptive information of the object

Geographic information

The geographical information can be defined as a localized representation of reality in Time and space.


It has two components: spatial data (sometimes linked by Rules of behavior) and attributes data.

Spatial data
Spatial data represent geographic objects associated with their location in the world real (localized data). Geographic objects are represented on maps as points, lines, and polygons.

Attribute data
The attribute data describe specific properties of geographic objects such as The number of a parcel, the width of a bridge, vegetation type...A powerful capability of GIS lies in the link between spatial data and data Allottees. For example, a plot is numbered. These two items illustrate the relationship Between space and the attribute.

Combine the two types of data
A GIS links the spatial and attributes data to perform various operations such as:
- The map display of geographic objects and their description
- The question of geographic databases
- The geographical analysis

The rules of behavior
Each spatial object has its own rules of behavior with respect to objects surrounding it. They must sometimes be taken into account in the study of a geographical area.
For example, in reality, a national road never cut a highway. These different rules can be easily defined and stored in geodatabases.

Combine the two types of data
GIS links the spatial and attributes data to perform various operations such as:
- The map display of geographic objects and their description
- The question of geographic databases
- The geographical analysis

The rules of behavior
Each geographic object has its own rules of behavior in relation to objects surrounding it. They must sometimes be taken into account in the study of a geographical area.
For example, in reality, a road never cut a highway. These different rules can be easily defined and stored in geodatabases. - L’interrogation de bases de données géographiques

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Organize data in a GIS

A GIS organizes geographic information as Layers (also called themes, layers, maps ...)
Each layer represents a set of similar data

Organization of data in a GIS:

A geographic database is the heart of a GIS because it allows storing spatial data but also attributes data. It consists of a series of geographic information layers organized effectively to be used by one or more applications.

Themes Geographical Information
Geographic entities (geometric objects) are organized into layers of information. For example, a base map can be organized into layers such as administrative boundaries, network drainage, roads, EDF lines, or telephones. Entities can be organized according to what they represent (rivers or roads are linear features), but they are generally stored in separate layers because their attributes are different.

Related data
Geographical data are characterized by two components: spatial data and data Allottees. These two types of data have two different structures. They are connected by a single code Which is stored with both spatial data and attribute data.

•  The attribute data are stored in tables and are managed by a GIS or a Management System Relational Database (RDBMS).

•  Spatial data is stored in files and managed by the GIS.

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Data formats

Vector Format

Raster Format

Two different data formats can be used to store geographic information.
The "vector" file (or object) is used to represent and locate each object in the real world using geometric shapes while the raster format (or image) presents a picture of reality.

The "Vector" Format
The data in the format "vector" are used to define individually each object of reality by geometric shapes (entity) such as point, line, or polygon. Each object type is defined by a pair of coordinates X, Y (points) or a series of pair of coordinates X, Y (or lines polygons), each pair being connected to its neighbor by a rope.

The format "Raster"
The data in "raster" formats use a matrix of square cells (or pixels) to model real-world objects.
Only a single pair of coordinates indicating the coordinates of a corner the image (usually in the lower left corner), the number of rows and columns and the size of the cells are stored.
 Use this information to locate the image in geographic space.

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The different types of entities

Three basic shapes

Multipart Entities
The first item, there are several modes of representation
Example: rivers

GIS users are required to represent phenomena or real-world objects using different types of entities.

Base Features

There are three basic shapes used to represent real-world objects: points, lines, or polygons. These forms are often called geometric objects, geometric or type entities feature.

•  Points the Points define discrete locations which are too small to be represented by lines or surfaces, such as the locations of telephone booths or buildings.
•  Lines The lines represent too close geographical objects to be represented by surfaces (eg streets, sewer systems, ...) or the length of which is disproportionate to the width(eg streams, roads, ...) or linear features that have length but no area like elevation lines.
•  Surfaces The faces (or polygons) are closed elements that represent real-world entities such as departments, districts, parcels, soil types, or land use plans (POS).

Multipart entities

Basic Entities can sometimes be assembled multipart or composite entities. For example, multipoint entities represent sets of logical points. Instead of representing each tree individually multipoint type entity will consolidate all points with the same characteristic (an entity for all conifers, an entity for all hardwood ...).

Data Display mode

The choice of the mode of representation of geographic information often influences the display and information analysis. The same geographic object can be represented in different ways. In the above example, you can view two different representations of a river or by line type entities, or by polygon type entities.

TUTORIAL ARCGIS INTRODUCTION PART2