1_GISIntro

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GIS for Educators Topic 1: Introducing GIS

Objectives: Understanding what GISis and what it can beused for.

Keywords: GIS, Co!uter, "a!s,

#ata, InforationSyste, S!atia$, %na$ysis

Overview:

&ust as we use a word !rocessor to write docuents and dea$ with words on aco!uter, we can use a GIS applicationto dea$ with spatial informationona co!uter. GIS stands for 'Geographical Information System'. % GISconsists of:

Digital Data ' the geogra!hica$ inforation that you wi$$ view andana$yse using co!uter hardware and software.

Computer Harware' co!uters used for storing data, dis!$ayinggra!hics and !rocessing data.

Computer Software' co!uter !rogras that run on the co!uterhardware and a$$ow you to wor( with digita$ data. % software !rograthat fors !art of the GIS is ca$$ed a GIS %!!$ication.

)ith a GIS a!!$ication you can o!en digita$ a!s on your co!uter, create news!atia$ inforation to add to a a!, create !rinted a!s custoised to your

needs and !erfor s!atia$ ana$ysis.

*et+s $oo( at a $itt$e ea!$e of how GIS can be usefu$. Iagine you are a hea$thwor(er and you a(e a note of the date and !$ace of residence of every !atientyou treat.

*ongitude *atitude #isease #ate

-./0123 435.616756 "u!s 5385-8-11/

-.///- 435.616-76 "u!s -285-8-11/-./0010 435.651262 "u!s --8158-116

-./7261/ 435.6-1076 "eas$es 558158-116

-./77/50 435.6-56-6 "eas$es -8158-116

-./7-02 435.6-56-6 "eas$es 5181-8-116

-./7200/ 435.6-755- "eas$es --81-8-116

-./610- 435.6556// "u!s 1-81-8-116

-./3372 435.6521 Chic(en 9o -81-8-116

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If you $oo( at the tab$e above you wi$$ uic($y see that there were a $ot ofeas$es cases in &anuary and ;ebruary. Our hea$th wor(er recorded the $ocationof each !atient+s house by noting its $atitude and $ongitude in the tab$e. Usingthis data in a GIS %!!$ication, we can uic($y understand a $ot ore about the!atterns of i$$ness:

!ore a"out GIS:

GIS is a re$ative$y new fie$d 4 it started in the 5601+s. It used to be thatco!uterised GIS was on$y avai$ab$e to co!anies and universities that hade!ensive co!uter eui!ent.


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#hat is GIS Software $ a GIS %pplication&:

=ou can see an ea!$e of what a GIS %pplication$oo(s $i(e in I$$ustration 5above. GIS %!!$ications are nora$$y !rogras with a gra!hica$ user interfacethat can be ani!u$ated using the ouse and (eyboard. ;i$e, Edit etc.? which, when

c$ic(ed using the ouse, show a !ane$ of actions.


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the $ayer order is done by c$ic(ing on a $ayer in the $egend, ho$ding the ousebutton down and then dragging the $ayer to a new !osition. In I$$ustrations 6and 51be$ow, the a! $egend is shown as the area to the $eft of the GIS%!!$ication window. By changing the $ayer order, the way that $ayers are drawncan be adjusted ' in this case so that rivers are drawn over the roads instead ofbe$ow the.

Getting a GIS %pplication for your own computers(:


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geogra!hica$ data?. In fact, the GIS %!!$ication can store any !ieces ofinforation which are associated with each !$ace ' soething that !a!er a!s

are not very good at. ;or ea!$e, our hea$th care wor(er cou$d store the!erson+s age and gender on her tab$e. )hen the GIS %!!$ication draws the$ayer, you can te$$ it to draw the $ayer based on gender, or based on diseasety!e, and so on. So, with a GIS %!!$ication we have a way to easi$y change thea!!earance of the a!s we created based on the non4geogra!hica$ dataassociated with !$aces.

GIS Systes wor( with any different ty!es of data. *ector atais stored asa series of ,= coordinate !airs inside the co!uter+s eory. Fector data isused to re!resent !oints, $ines and areas. I$$ustration 55be$owshows differentty!es of vector data being viewed in a GIS a!!$ication. In the tutoria$s thatfo$$ow we wi$$ be e!$oring vector data in ore detai$.

+aster ataare stored as a grid of va$ues. see i$$ustrations 5-and 53be$ow?. In fact these b$oc(s are the individua$ ce$$sof the data grid that a(es u! the raster iage. )e wi$$ be $oo(ing at rasterdata in greater detai$ in $ater tutoria$s.

Illustration 11: 0ector data is used to represent points e.g. towns, linese.g. rivers and polygons e.g. municipal "oundaries.


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#hat have we learne&

*et+s wra! u! what we covered in this wor(sheet: % GISis a syste of co!uter hardware, co!uter software and

geogra!hica$ data. % GIS %pplicationa$$ows you to view geogra!hica$ data and is an

i!ortant !art of the GIS. % GIS %!!$ication nora$$y consists of a menu "ar, tool"ars, a map

viewand a legen. *ectorand rasterdata are geogra!hica$ data used in a GIS a!!$ication.

Geographicaldata can have associated non)geographicaldata.

,ow you try-

ere are soe ideas for you to try with your $earners:

Geography:#escribe the conce!t of GIS to your $earners as out$ined inthis tutoria$. %s( the to try to thin( of 3 reasons why it ight be handyto use a GIS instead of !a!er a!s. ere are soe that we cou$d thin( of: GIS %!!$ications a$$ow you to create any different ty!es of a!s

fro the sae data. GIS is a great visua$isation too$ that can show you things about your

data and how they are re$ated in s!ace >e.g. those disease outbrea(swe saw ear$ier?.

9a!er a!s need to be fi$ed and are tie consuing to view.


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Soeties !eo!$e do bad things to the the environent, $i(e du!ingdangerous cheica$s that (i$$ !$ants and ania$s. Using raster datafro sate$$ites can he$! us to onitor for these ty!e of !rob$es.

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