Detection of land cover changes by principle components analysis of spot hrv data : Case study : houd el-remal coastal area, el-beheira,egypt

الملخص EN

The pressure of population on land and its limited resources is a major factor affecting sustainable development in Egypt.

Whether by over- exploitation or mismanagement, changes in land use, and therefore land cover, are taking place at an unprecedented rate that makes these lands prone to degradation.

Principal components analysis (PCA) has proved to be a powerful tool for detection of change and monitoring rates of land cover changes.

The present paper demonstrates the application of PCA on high-resolution satellite image data (SPOT-HRV) to detect land cover changes that have occurred in Houd El-Remal area, El-Beheira governorate, on the northern coastal desert of Egypt.

This area was subjected to agricultural reclamation activities by continuous sand filling of its lowlands using the sand of the dunes that exist in the vicinity, and irrigation using the deltaic untreated drainage water.

This untreated drainage water is highly saline and is not re-drained again after irrigation.

When salinity develops as a consequence of the above situation, lands are refilled again by transporting sand from the dunes and adding thick layers of sand for reactivating the land.

SPOT satellite imagery of two time frames, 1986 and 1995, were analyzed using comparative classification and spectrally-based PCA to examine the status of the major land cover classes of Houd El-Remal area and to monitor the rate of change in agricultural and urban extensions.

The land cover changes observed were: changes in structure of the dunes habitat due to human activities, soil salinization due to irrational land reclamation, and urban sprawl due to expanding population.

It was concluded that the methodology adopted for analyzing SPOT-HRV imagery was useful in assessing and monitoring land cover changes and provided valuable information to planners and decision makers in formulating land use policies, and in allocating resources in the area under study.

The study also demonstrated the immense human impacts on natural coastal habitats and loss of its natural resources, mainly sand dune.

This calls for careful use of these ecologically fragile habitats and the need for conserving its biodiversity.