Thesis (MA.)--Stellenbosch University, 2001. / ENGLISH ABSTRACT: There are many reasons to conserve fynbos. Not only does fynbos form part of the
Cape floral kingdom, one of the richest floral kingdoms in the world, but the
contribution that it makes to the regional economy through utilisation, education,
recreation and tourist opportunities is immeasurable.
Fire plays an integral role in fynbos ecosystems. According to Van Wilgen,
Richardson & Seydack (1994: 322) " ... managing fynbos equates to managing fire".
Therefore managers need accurate fire information about a fynbos area to manage it
properly. This is where satellite remote sensing can provide the manager with useful
information about the fire regime. In other words, satellite remote sensing can help a
manager establish where and when an area has burnt.
Using readily available satellite data, this study attempts to establish (through
comparison) what techniques would be most suitable and affordable to compile a fire
information database. Landsat Thematic Mapper data from 1990 - 1996 of the southwestern
Cape was used and compared with existing fire records of the area.
The results show that techniques such as supervised and unsupervised classification
are reliable in identifying burnt areas, but a major drawback of these techniques is that
they require a large amount of user input and knowledge. They are thus not regarded
as simple or easily repeatable. -
The' more simple techniques like image differencing and image ratioing were also
found to be reliable in identifying burnt areas. These techniques require less user input
and in some instances less data (image bands) to produce similar (or better) results
than supervised and unsupervised classification techniques.
The results show that differencing temporally different Images, obtained from
applying principle components analysis, produces reliable results with very little
confusion and little user input. Using such a technique could enable users to procure
only two bands of Landsat data and still produce reliable fire information for
managing a fynbos ecosystem. / AFRIKAANSE OPSOMMING: Daar is verskeie redes waarom fynbos bewaar moet word. Nie net vorm dit deel van
een van die rykste blommeryke in die wereld nie, maar die bydrae wat dit tot die
streeksekonomie maak, deur die benutting van veldblomme en die geleenthede wat dit
bied vir toerisme en ontspanning, is enorm.
Vuur speel 'n belangrike rol in die bestuur van fynbos ekosisteme. Soos beklemtoon
deur Van Wilgen, Richardson & Seydack (1994: 322) se stelling: " ... managing
fynbos equates to managing fire". Om hierdie rede is dit belangrik dat 'n bestuurder
akkurate inligting oor die verspreiding van veldbrande moet he. Satellietafstandwaarneming
kan hier 'n belangrike rol speel deur sulke inligting te verskaf
Deur gebruik te maak van maklik bekombare satellietdata, poog hierdie studie om te
bepaal (d.m.v. vergelyking) watter tegnieke die mees geskikte is in terme van
bekostigbaarheid en gebruikersvriendelikheid. Landsat Thematic Mapper data van
1990 tot 1996 van die suidwes-Kaap is gebruik en vergelyk met bestaande branddata
van die studiegebied.
Daar is gevind dat tegnieke soos gerigte en nie-gerigte klassifikasie in staat is om
gebrande dele betroubaar uit te ken. Hierdie tegnieke verg egter baie insette en kennis
van die gebruiker en is ook nie maklik om jaar na jaar te herhaal nie. Daarom word
hierdie tegnieke nie aanbeveel nie.
Daar is gevind dat die eenvoudiger tegnieke soos veranderingsanalise ook gebrande
dele betroubaar kon uitken. Hierdie tegnieke het die voordeel dat die gebruiker nie
baie' kennis van die gebied hoef te he nie en ook nie so baie insette hoef te lewer nie.
Hierdie tegnieke word bo gerigte en nie-gerigte klassifikasie aanbeveel. -
Die resultate dui daarop dat betroubare resultate verkry kan word deur tempo reel
verskillende beeIde, verkry deur hoofkomponentanalise, van mekaar af te trek.
Hierdie tegniek vereis relatief min gebruikersinsette en daar kan selfs met slegs twee
Landsat bande gewerk word. So 'n tegniek kan beslis 'n bekostigbare en effektiewe
manier wees om nodige inligting vir die bestuur van 'n fynbos ekosisteem te bekom.
| Identifer | oai:union.ndltd.org:netd.ac.za/oai:union.ndltd.org:sun/oai:scholar.sun.ac.za:10019.1/52064 |
| Date | 12 1900 |
| Creators | Smit, Walter J. (Walter Johan) |
| Contributors | Van Niekerk, A., Stellenbosch University. Faculty of Arts and Social Sciences. Dept. of Geography and Environmental Studies . |
| Publisher | Stellenbosch : Stellenbosch University |
| Source Sets | South African National ETD Portal |
| Language | en_ZA |
| Detected Language | Unknown |
| Type | Thesis |
| Format | 73 p. : ill. |
| Rights | Stellenbosch University |
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