module 1 - familiarization with quantum gis

8/9/2019 Module 1 - Familiarization With Quantum GIS

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MODULE 1:

FAMILIARIZATION WITH QUANTUM GIS

Training on Geographic Information System using Quantum GIS

NATIONAL ECONOMIC DEVELOPMENT AUTHORITY

REGIONAL DEVELOPMENT COORDINATION STAFF

November 5 9, 12 16, 2012


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Module 1: Familiarization with Quantum GIS

OVERVIEW:

GIS stands for 'Geographical Information System'. A GIS consists of:

Digital Datathe geographical information that you will view and analyse using computer hardware and

software.

Computer Hardwarecomputers used for storing data, displaying graphics and processing data.

Computer Softwarecomputer programs that run on the computer hardware and allow you to work with

digital data. A software program that forms part of the GIS is called a GIS Application. An example of a GIS

application is Quantum GIS.

With Quantum GIS (or QGIS) you can open digital maps in your computer similar to opening and working with

document files in Microsoft Word or OpenOffice Word Processor. With QGIS you can create new spatial map

information from old spatial data, design and create printed maps easily, and perform spatial analysis.

STARTING A QGISSESSION:

QGIS is a user friendly Open Source Geographic Information System (GIS) licensed under the GNU General Public

License. The current version as of the writing of this manual is v 2.4.0 Chugiak. The installer can be downloaded

from the download page of QGIS website http://www.qgis.org.It is assumed that the software will be running in

Windows OS.

After installation, there are two main options in running the application: Starting a new session or Opening an

existing session.

STARTING A NEW SESSION THRU THE WINDOWS START MENU:

Press the StartMenu, usually on the lower left of the Computer Desktop Interface, and then select All Programs.

From here, select the program folder QGIS Chugiak, and then QGIS Desktop (2.4.0). The QGIS banner will appear

and shortly the main interface of QGIS will show and QGIS Tips window. You have a working QGIS sessionnow.

Read and close the QGIS Tips window and study the main interface.

Press the

windows Start

menu

Select All

Programs

Select QGIS

Desktop (2.4.0)

QGIS starts
http://www.qgis.org/http://www.qgis.org/http://www.qgis.org/http://www.qgis.org/


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OPENING AN EXISTING QGISPROJECT SESSION:

If there is an existing QGIS session (NOTE: for this activity a project session is already been created), opening it is

simply done by double clickingthe .qgs file. In your computer the folder Module 1 / Datasetcontains shapefiles

(.shp, .dbf, .shx etc) and qgis file (.qgs). QGIS file saves the sessions environment (map scale, symbology etc) when

you are working on your GIS data. Opening this file will also load the GIS data in that session.

FAMILIARIZING THE QGISINTERFACE:

Below is a snapshot of a QGIS working session with data already been loaded. QGIS application is design to have a

user friendly graphical user interface (GUI) that can be manipulated using the mouse and keyboard.

Menus

Toolbars

Browser

Layer List

Map View

Status Bar

Double click the file

Module 1.qgs will

open the QGIS

project session


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MENUS:

The application provides Menus near to the top of the window (File, Edit etc.) which, when clicked using the

mouse, shows a panel of actions. These actions provide a way for you to tell QGIS what you want to do. For

example you may use the menus to tell the GIS Application to add a new layer to the display output.

TOOLBARS:

Toolbars(rows of small pictures/icons that can be clicked with the mouse) normally sit just below the menus and

provide a quicker way to use frequently needed actions such as map navigations, adding data, or saving the

session. Holding your mouse over a picture will usually tell you what will happen when you click on it. This is called

a tooltip.

By default, when you first run the QGIS application, it will show a lot of unnecessary toolbars. For beginners, this is

somewhat overwhelming. To customize the interface and to show just the most needed toolbars, right click your

mouse on an area near the toolbars or menus.

Click Layer

menu, then

Add Vector

Layer

Action will

make this

dialog box

appear

Right click near

the Menus or

Toolbars

Select these 5

toolbars

See change in

the interface

Hold your

mouse over

this icon

Tooltip

shows with

information

on the action


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LAYER PANEL:

A basic function of QGIS is to display map layers. Layersare stored as files on a disk or as records in a database. An

example of common data format for map layers is the shapefile (.shp). The shapefileformat defines the geometry

and attributesof geographically referenced features. More on this will be discussed on the next module. Normally

each map layer will represent something in the real world South_Cotabato_Bounds layer represents

administrative barangay boundary and South_Cotabato_POI_Tourism layer represents the tourism spots in the

area. The Layers Toolbar (or the Layer Panel) shows the spatial layer (be a shapefile or other files) loaded in your

QGIS session.

MAP VIEW:

When you open a layer in the QGIS it will appear in the map view. The Map Viewshows a graphic representing

your layer. It provides a dynamic visualization of the active data layers that can be mapped. When you add more

than one layer to a map view, the layers are overlaid on top of each other.

STATUS BAR:

Status barprovides some vital information about the current project settings. Information such as the coordinates

(X, Y) of the cursor position can be seen in the status bar. Scale of the zoom level and the coordinate and

projection system EPSG can also be found in the status bar. EPSGwhich stands for European Petroleum Survey

Group is a standard code to define geodetic parameters in mapping. Some of the most used EPSG codes are: EPSG:

4326 (WGS84) EPSG: 900913 (Google Projection) and EPSG: 32651 (UTM 51N/ WGS84)

NAVIGATING AND IDENTIFYING THE MAP:

Map navigationtoolbar provides a simple set of tools to help you navigate with the display. This set includes pan

and zoom tools in different modes. In order to use the tool, you must enable it by clicking the respective iconin

the toolbar. Tooltipcan help you identify the different modes of navigation.

Data added in

QGIS session

appears here

Multiple dataloaded are

overlaid on top

of each other.


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Aside from navigating the map, the usual operation in a GIS session is to instantly identify featuresfrom a layer.

Attributetoolbar provides a set of tools to instantly get information from an active layer. Aside from identify tool,

selecting/deselecting a feature are some of the most used tools in GIS session. Open attributetable is also found

in the Attribute tool which is very useful when dealing with the data stored in the database of the layer. Other

handy tools are the Measure, Map Tips(similar to Tooltip) and Selection Tools.

SAVING THE QGISSESSION:

After you finish working with the QGIS session, saving the project in .qgs file will allow you to continue the currentGIS environment in another session (in another day). The Filetoolbar or the File menu has tools that deals with the

qgs file. The QGIS Project file will basically save the status and the working session environment of the QGIS.

NOTE:Saving the project will not save the edits you have done with the data layers. There is a separate saving

protocol for the layer which will be discussed in Module 5 and Module 6.

Click Save Project As in the File toolbar

OR the File menu

Type Module 1 A in the dialog box that

appears.


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WRAP UP

In this module, you have learned to work with the Quantum GIS user interface. Just like other modern GIS

application, Quantum GIS has this Windows look-and-feel that is easy to learn. In order to work with QGIS, the user

will actively select or pick a command from the different functions/ tools offered by QGIS. Dialog boxes and pop up

window similar to a wizard type instructions and steps will then guide the user to the succeeding procedure until

the final result is achieved.

For first time GIS users, GIS functions usually operate in multiple steps, with the user supplying information in the

parameters defined by the function. Thus it is important to read and follow the dialog boxes and pop up window

that show up in every command that you use in QGIS. For more details on the different tools, you can always refer

to the QGIS manual online or the downloaded pdf version of it. The site is

http://docs.qgis.org/html/en/docs/user_manual/index.html

For more tutorials online, you can also visit:

http://docs.qgis.org/html/en/docs/gentle_gis_introduction/index.html

http://qgis.spatialthoughts.com/
http://docs.qgis.org/html/en/docs/user_manual/index.htmlhttp://docs.qgis.org/html/en/docs/user_manual/index.htmlhttp://docs.qgis.org/html/en/docs/gentle_gis_introduction/index.htmlhttp://docs.qgis.org/html/en/docs/gentle_gis_introduction/index.htmlhttp://qgis.spatialthoughts.com/http://qgis.spatialthoughts.com/http://qgis.spatialthoughts.com/http://docs.qgis.org/html/en/docs/gentle_gis_introduction/index.htmlhttp://docs.qgis.org/html/en/docs/user_manual/index.html

module 1 - familiarization with quantum gis

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