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Kustöversvämningar och GIS : en studie om skånska kustnära kommuners arbete samt interpolationsmetodens betydelse av höjddata vid översvämningssimulering

Ceric, Nina and Elgh Dalgren, Sanna (2009) In Lunds universitets Naturgeografiska institution - Seminarieuppsatser
Dept of Physical Geography and Ecosystem Science
Abstract
Global warming is causing rising sea levels due to melting of land ice and thermal
expansion of water. This could lead to serious consequences around the world,
such as environmental refugees.
In case of a radical sea level rise, Sweden faces big challenges because many
people live along the coasts. This thesis includes a study on how the Scanian
coastal municipalities attack the problem of preventing coastal flooding. Their
work has been explored and the results show that the municipalities are at various
stages of progress. A first approach is usually to map the areas at risk in the event
of sea level rise. This work is usually distributed to consultants and it is done
preferably with coastal flood simulations in GIS.
The... (More)
Global warming is causing rising sea levels due to melting of land ice and thermal
expansion of water. This could lead to serious consequences around the world,
such as environmental refugees.
In case of a radical sea level rise, Sweden faces big challenges because many
people live along the coasts. This thesis includes a study on how the Scanian
coastal municipalities attack the problem of preventing coastal flooding. Their
work has been explored and the results show that the municipalities are at various
stages of progress. A first approach is usually to map the areas at risk in the event
of sea level rise. This work is usually distributed to consultants and it is done
preferably with coastal flood simulations in GIS.
The possibility to simulate coastal flooding was looked at in four GIS programs,
and it proved to be limited. It is possible to perform the analysis in most GIS
programs but it requires great knowledge and the analysis must be performed in
many steps, leading to increased risk of errors.
The condition for a costal flooding analysis to be carried out is access to
continuous elevation data, usually interpolated from elevation-points. It is
important that the elevation data is of good quality, which requires high accuracy
of the raw data but also a good interpolation. There are many interpolation
methods whereof three (inverse distance weighting, kriging and topo to raster
(ArcGIS specific)) were compared in this study. In total 16 interpolations were
conducted, whose RMSE (Root Mean Square Error) values were calculated as a
measure of accuracy. The best interpolation method was kriging, based on
experimental semivariograms. All interpolations had greater RMSE values than
the raw data decimeter accuracy. In addition, coastal flooding simulations were
performed for all interpolation methods, for 15 levels of sea rise. The result was
that the flooded areas differ substantially depending on interpolation method. (Less)
Abstract (Swedish)
Den globala uppvärmningen orsakar stigande havsnivåer till följd av avsmältning
av landis samt termisk expansion av vattnet. Allvarliga konsekvenser befaras till
följd av detta, stora landarealer kan komma att svämmas över vilket bland annat
kan bidra till klimatflyktingar.
Om havsnivån ökar drastiskt står vi i Sverige inför väldiga utmaningar eftersom
stora delar av befolkningen är bosatta längs landets kuster. Detta examensarbete
innefattar en studie om hur de skånska kustnära kommunerna antar utmaningen
att förebygga kustöversvämningar. Deras arbete har utforskats där resultaten visar
att kommunerna har kommit olika långt. Ett första angreppssätt är oftast att ta
reda på vilka områden som riskerar att drabbas vid en eventuell... (More)
Den globala uppvärmningen orsakar stigande havsnivåer till följd av avsmältning
av landis samt termisk expansion av vattnet. Allvarliga konsekvenser befaras till
följd av detta, stora landarealer kan komma att svämmas över vilket bland annat
kan bidra till klimatflyktingar.
Om havsnivån ökar drastiskt står vi i Sverige inför väldiga utmaningar eftersom
stora delar av befolkningen är bosatta längs landets kuster. Detta examensarbete
innefattar en studie om hur de skånska kustnära kommunerna antar utmaningen
att förebygga kustöversvämningar. Deras arbete har utforskats där resultaten visar
att kommunerna har kommit olika långt. Ett första angreppssätt är oftast att ta
reda på vilka områden som riskerar att drabbas vid en eventuell havsnivåökning.
Detta arbete distribueras ofta på konsulter och utförs vanligtvis med hjälp av
kustöversvämningssimuleringar i GIS.
Möjligheten att simulera kustöversvämningar undersöktes i fyra GIS-program,
vilken visade sig vara begränsad. Det är möjligt att utföra analysen i de flesta
GIS-program men det krävs stor kunskap hos användaren och analysen måste
utföras i många steg, vilket medför ökad risk för fel.
Förutsättningen för att en översvämningsanalys ska kunna genomföras är tillgång
till kontinuerlig höjddata, som normalt interpoleras fram från höjdpunkter. Det är
viktigt att höjddata är kvalitativ för en bra analys vilket förutsätter hög
noggrannhet på rådata men även en bra interpolering. Det finns många
interpolationsmetoder varav tre (avståndsviktad medelvärdesinterpolation, kriging
och topo to raster) jämförs i detta arbete. Totalt utfördes 16 interpolationer vars
RMSE-värden beräknades som ett mått på noggrannheten. Den bästa
interpolationsmetoden var kriging baserad på experimentella semivariogram.
Samtliga interpolationer hade markant större genomsnittsfel (RMSE-värden) än
rådatas decimeternoggrannhet. Dessutom utfördes kustöversvämningssimuleringar
för samtliga interpolationsmetoder för 15 stigande havsnivåer.
Utslaget blev att de översvämmade areorna skiljer sig väsentlig med
interpolationsmetod. (Less)
Please use this url to cite or link to this publication:
author
Ceric, Nina and Elgh Dalgren, Sanna
supervisor
organization
year
type
H2 - Master's Degree (Two Years)
subject
keywords
interpolationer, Skåne, GIS, kustöversvämningar, RMSE
publication/series
Lunds universitets Naturgeografiska institution - Seminarieuppsatser
report number
169
language
Swedish
additional info
Karin Gullstrand och Björn Almström, vid SWECO AB, Malmö.
id
1858605
date added to LUP
2011-03-24 16:48:46
date last changed
2011-12-19 12:06:28
@misc{1858605,
  abstract     = {Global warming is causing rising sea levels due to melting of land ice and thermal
expansion of water. This could lead to serious consequences around the world,
such as environmental refugees.
In case of a radical sea level rise, Sweden faces big challenges because many
people live along the coasts. This thesis includes a study on how the Scanian
coastal municipalities attack the problem of preventing coastal flooding. Their
work has been explored and the results show that the municipalities are at various
stages of progress. A first approach is usually to map the areas at risk in the event
of sea level rise. This work is usually distributed to consultants and it is done
preferably with coastal flood simulations in GIS.
The possibility to simulate coastal flooding was looked at in four GIS programs,
and it proved to be limited. It is possible to perform the analysis in most GIS
programs but it requires great knowledge and the analysis must be performed in
many steps, leading to increased risk of errors.
The condition for a costal flooding analysis to be carried out is access to
continuous elevation data, usually interpolated from elevation-points. It is
important that the elevation data is of good quality, which requires high accuracy
of the raw data but also a good interpolation. There are many interpolation
methods whereof three (inverse distance weighting, kriging and topo to raster
(ArcGIS specific)) were compared in this study. In total 16 interpolations were
conducted, whose RMSE (Root Mean Square Error) values were calculated as a
measure of accuracy. The best interpolation method was kriging, based on
experimental semivariograms. All interpolations had greater RMSE values than
the raw data decimeter accuracy. In addition, coastal flooding simulations were
performed for all interpolation methods, for 15 levels of sea rise. The result was
that the flooded areas differ substantially depending on interpolation method.},
  author       = {Ceric, Nina and Elgh Dalgren, Sanna},
  keyword      = {interpolationer,Skåne,GIS,kustöversvämningar,RMSE},
  language     = {swe},
  note         = {Student Paper},
  series       = {Lunds universitets Naturgeografiska institution - Seminarieuppsatser},
  title        = {Kustöversvämningar och GIS : en studie om skånska kustnära kommuners arbete samt interpolationsmetodens betydelse av höjddata vid översvämningssimulering},
  year         = {2009},
}