Shalaby, A. & Gad, A.

Transcription

1 Urban Sprawl Impact Assessment on the Fertile Agricultural Land of Egypt Using Remote Sensing and Digital Soil Database, Case study: Qalubiya Governorate Shalaby, A. & Gad, A. National Authority for Remote Sensing and Space Sciences, Egypt 1

2 Motivations The ever increasing population and urban sprawl in addition to land degradation causes a huge pressure on the limited agricultural land and decrease in area per capita. The amount, the rate and the intensity of urban sprawl and lose of agricultural land need to be analyzed. 2

3 Introduction Urban sprawl is one of the main problems that threaten the limited highly fertile land in the Nile Delta of Egypt. Urbanization is an inevitable process due to progress and development however the encroachments of urban settlements on expense of agricultural lands may pose dire consequences. Therefore, changes of the land covers and the environmental impact of these changes should be carefully considered. For this purpose 3

4 Objectives To study the urban sprawl using multi-temporal satellite data Integrating remote sensing and GIS in studying the spatial distribution of urban sprawl and its impact on agricultural land. 4

5 Study area of Al-Qalubiya Governorate The Qalubiya Governorate is located on the eastern side of the River Nile, near the Delta head. It is bounded from the south by both Cairo and Giza Governorates, from the north by Dakahlia and Gharbia Governorates, from the east by El-Sharkia Governorate and from the west by El-Monofia Governorate.

6 Climate of the study Area * The climatic data of Qalubiya Governorate indicate that the total rainfalls does not exceed 7.2 mm/year. The mean minimum and maximum annual temperatures are 16.5 and 31.0 C, respectively. * The evaporation rates are coinciding with temperatures, where the lowest evaporation rate (1.9 mm/day) was recorded in January, while the highest value (7.6 mm/day) was recorded in June. * Qalubiya Governorate is located under arid climatic conditions. 6

7 Materials Satellite data (TM, ETM+, and Egypt Sat-1 Topographic maps (Scale 1-50,000) Field data Digital soil database 7

8 Methodology flowchart Landsat TM 1993 Landsat ETM Egypt Sat-1, 2009 Geo-referencing & rectification Geo-referencing & rectification Geo-referencing & rectification Supervised classification Visual interpretation Supervised classification Visual interpretation Supervised classification Visual interpretation Land cover Map 1987 Integration using GIS Interprete d map Land cover Map 2001 Integration using GIS Interpreted map Land cover Map 2001 Integration using GIS Interprete d map Higher accuracy map 1993 Higher accuracy map 2001 Higher accuracy map 2001 Post-classification change detection Change detection map tabular data 8

9 Field work Field work has been carried out to collect ground truth for image classification and soil samples for soil mapping Vertic Torrifluvents soil sub-great group 9

10 Typic Torriorthents soil sub-great group 10

11 Image enhancement and visual interpretation The goal of image enhancement is to improve the visual interpretability of an image The purpose is to optimize the complementary abilities of the human mind and the computer. Because the mind is excellent at interpreting spatial attributes and identifying obscure features (Lillesand and Kiefer, 1994). 11

12 FCC, 4,3,2, of TM

13 FCC, 4,3,2, of ETM

14 FCC, 3,2,1, of Egypt Sat-1,

15

16

17

18 Area (km2) Area (km2) 0 year Area (km2) Urban sprawl from

19 Urban areas of 1992 overlaid on Capability map, Awal Shobra district 19

20 Urban areas of 2001 overlaid on Capability map, Awal Shobra district 20

21 Urban areas of 2009 overlaid on Capability map, Awal Shobra district 21

22 Area (km2) Area (km2) year Area (km2) Urban sprawl from

23 Conclusion Integrating visual interpretation with supervised classification led to increase in the overall accuracy. The study area has undergone a very severe land cover changes; increase in urban settlements and decrease in agricultural land, Integrating GIS and remote sensing provided valuable information e.g.. Area and spatial distribution urban expansion. The closer the district to Cairo the faster the urban sprawl 23