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Assessing salinization, sand encroachment and expanding urban areas in the Nile Valley using Landsat MSS data

Brogaard, Sara and Falkenström, Helén (1995) In Lunds universitets Naturgeografiska institution - Seminarieuppsatser
Dept of Physical Geography and Ecosystem Science
Abstract (Swedish)
Jordförstöring och utbredning av urbana områden är allvarliga hot mot Egyptens jordbruk och ekonomi, samt försvårar försörjningen av den snabbt växande befolkningen. Landsat MSS bilder från tre år; 1972, 1986 och 1992, har använts för att studera försaltning, försandning och urbanisering i Nildalen, mellersta Egypten. 1992 års bild klassades enligt maximum likelihood-metoden och enligt regressionsbaserade metoder. En förändringsstudie byggd på post-klassificeringsprincipen utfördes på de tre bilderna. Trots försök att förstärka jordens spektrala reflektans genom att beräkna ett jordindex var ett återkommande problem i studien växtlighetens dominans av reflektansen. Att klassificera försaltning genom digital analys av MSS data visade sig... (More)
Jordförstöring och utbredning av urbana områden är allvarliga hot mot Egyptens jordbruk och ekonomi, samt försvårar försörjningen av den snabbt växande befolkningen. Landsat MSS bilder från tre år; 1972, 1986 och 1992, har använts för att studera försaltning, försandning och urbanisering i Nildalen, mellersta Egypten. 1992 års bild klassades enligt maximum likelihood-metoden och enligt regressionsbaserade metoder. En förändringsstudie byggd på post-klassificeringsprincipen utfördes på de tre bilderna. Trots försök att förstärka jordens spektrala reflektans genom att beräkna ett jordindex var ett återkommande problem i studien växtlighetens dominans av reflektansen. Att klassificera försaltning genom digital analys av MSS data visade sig omöjligt, huvudsakligen på grund av dess spridda förekomst och frånvaron av saltkrustor. Korrelationer och klassningsnoggrannheter var relativt höga i försandningsstudien; r=O,54-0,82, OAA=55-89 %. Även om den obrukade landremsan mellan dalen och nyodlingsområdet lätt kunde klassificeras, så kunde den gradvisa förändringen av jordsammansättningen i den brukade dalen inte urskiljas. Likheter i material mellan bebyggelsen i övergångszonen till öknen och intilliggande barmark gjorde det svårt att separera dessa två klasser. Förändringsstudien antydde att den bebyggda markens utbredning ökat med 29 % från 1972 till 1992. En konsekvent utförd manuell redigering av klassningarna hade troligtvis resulterat i en ännu högre
siffra. (Less)
Abstract
Soil degradation and expanding urban areas are serious threats to the Egyptian agriculture and economy, and jeopardize the possibility to provide food to the rapidly growing population. Landsat MSS scenes from the years of 1972, 1986 and 1992 have been used to study salinization, sand encroachment and urbanization in the Nile valley in Middle Egypt. The 1992 data set were classified according to the maximum likelihood procedure as well as the regression-based procedure. A change detection based on the post-classification approach was carried out on the three scenes. Despite efforts to enhance the spectral reflectance of soil by the computation of a soil index, a general problem in the study was the masking effect by vegetation of the soil.... (More)
Soil degradation and expanding urban areas are serious threats to the Egyptian agriculture and economy, and jeopardize the possibility to provide food to the rapidly growing population. Landsat MSS scenes from the years of 1972, 1986 and 1992 have been used to study salinization, sand encroachment and urbanization in the Nile valley in Middle Egypt. The 1992 data set were classified according to the maximum likelihood procedure as well as the regression-based procedure. A change detection based on the post-classification approach was carried out on the three scenes. Despite efforts to enhance the spectral reflectance of soil by the computation of a soil index, a general problem in the study was the masking effect by vegetation of the soil. Classifying salinization by digital analysis of MSS data proved to be impossible mainly due to its patchy occurrence and the absence of salt crusts. Correlations and classification accuracies were relatively high for the sand encroachment study; r=O.54-0.82, OAA=5589 %. Although the non cultivated land strip between the valley and the reclaimed land could easily be classified, the gradual changes in soil composition of the cultivated floodplain could not be discerned. Difficulties in separating urban land in the desert fringe zone from adjacent bare land arose from similarities in material. The change analysis indicated an increase of 29 % of urban land from 1972 to 1992. Consistency in the editing of the classifications had probably resulted in even higher figures. (Less)
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author
Brogaard, Sara and Falkenström, Helén
supervisor
organization
year
type
H1 - Master's Degree (One Year)
subject
keywords
geography, physical geography, salinization, sand encroachment, Nile Valley, Landsat MSS data
publication/series
Lunds universitets Naturgeografiska institution - Seminarieuppsatser
report number
35
funder
SIDA, Minor Field Study programme (MFS)
language
English
id
2061985
date added to LUP
2011-11-14 13:33:53
date last changed
2011-11-14 13:35:39
@misc{2061985,
  abstract     = {Soil degradation and expanding urban areas are serious threats to the Egyptian agriculture and economy, and jeopardize the possibility to provide food to the rapidly growing population. Landsat MSS scenes from the years of 1972, 1986 and 1992 have been used to study salinization, sand encroachment and urbanization in the Nile valley in Middle Egypt. The 1992 data set were classified according to the maximum likelihood procedure as well as the regression-based procedure. A change detection based on the post-classification approach was carried out on the three scenes. Despite efforts to enhance the spectral reflectance of soil by the computation of a soil index, a general problem in the study was the masking effect by vegetation of the soil. Classifying salinization by digital analysis of MSS data proved to be impossible mainly due to its patchy occurrence and the absence of salt crusts. Correlations and classification accuracies were relatively high for the sand encroachment study; r=O.54-0.82, OAA=5589 %. Although the non cultivated land strip between the valley and the reclaimed land could easily be classified, the gradual changes in soil composition of the cultivated floodplain could not be discerned. Difficulties in separating urban land in the desert fringe zone from adjacent bare land arose from similarities in material. The change analysis indicated an increase of 29 % of urban land from 1972 to 1992. Consistency in the editing of the classifications had probably resulted in even higher figures.},
  author       = {Brogaard, Sara and Falkenström, Helén},
  keyword      = {geography,physical geography,salinization,sand encroachment,Nile Valley,Landsat MSS data},
  language     = {eng},
  note         = {Student Paper},
  series       = {Lunds universitets Naturgeografiska institution - Seminarieuppsatser},
  title        = {Assessing salinization, sand encroachment and expanding urban areas in the Nile Valley using Landsat MSS data},
  year         = {1995},
}