224
E. Iwasaki et al.
Corona image of 1968 has a low spectral resolution (single band) and because
of that, many scholars hesitate to use it. In fact, some scholars have pointed out the
limitations of using Corona image due to its course spectral resolution (Single band).
Because they are panchromatic images (single layer images), they create difficulties
in usage during the auto classification process (Saleem et al. 2018).
However, it is the only source of satellite images in the 1960s and is a precious
source to understand the land use at the time when New Valley Project had just begun.
For this reason, the authors attempted to use source of images, keeping in mind the
difficulty and error risk of image processing.
(2) Site investigation data
A total number of 217 ground truth points for different land use and land cover
classes were collected during fieldwork in April 2013 and April 2016. These check
points are distributed among all villages of Dakhla Oasis including Rashda village.
The assigned land use classes are urban, bare land, water bodies, land under
reclamation, and sabkhas (salt flats).
(3) Well data
1
Information of well location, year of drilling, and type of wells were collected
in 2007. The information of well location is used to map their locations on the map
using GIS. Data and information were collected from about 70 wells and springs in
Rashda village by fieldwork. Also, through field checks in 2014 and 2016, a total of
25 government and local wells were investigated.
There are five types of wells; government well, local well, investment well, surface
spring, and the Roman spring.
(1) Government wells are generally deep wells and drilled by Ministry of Irrigation. There were 12 wells of this type in Rashda. (2) Local wells are usually less than
or equal to 85 m deep. This type of well is planned to last for 20 years. There were 29
wells of this type in Rashda. (3) Investment wells have a maximum depth of 500 m
and they are intended to last for 20–30 years. There were nine wells of this type in
Rashda. (4) Surface spring is as the name implies, has a depth less than 120 m. There
were about 34 surface springs of this type. The first one was constructed in 1998. (5)
Roman springs. They have a depth ranging from 85 to 100 m and they are exploited
by local farmers. There are eight springs of this type, but all of them have now dried
up.
Among these five types of wells, investment wells and surface springs have
increased since the end of 1990s.
3.2 Methods
Methods of analyzing the land use using satellite images followed 5 steps: (1) image
pre-processing and layer stacking, (2) image sub-setting, (3) image post processing,
1 See Chapter 12 on history of wells for more details.
E. Iwasaki et al.
Corona image of 1968 has a low spectral resolution (single band) and because
of that, many scholars hesitate to use it. In fact, some scholars have pointed out the
limitations of using Corona image due to its course spectral resolution (Single band).
Because they are panchromatic images (single layer images), they create difficulties
in usage during the auto classification process (Saleem et al. 2018).
However, it is the only source of satellite images in the 1960s and is a precious
source to understand the land use at the time when New Valley Project had just begun.
For this reason, the authors attempted to use source of images, keeping in mind the
difficulty and error risk of image processing.
(2) Site investigation data
A total number of 217 ground truth points for different land use and land cover
classes were collected during fieldwork in April 2013 and April 2016. These check
points are distributed among all villages of Dakhla Oasis including Rashda village.
The assigned land use classes are urban, bare land, water bodies, land under
reclamation, and sabkhas (salt flats).
(3) Well data
1
Information of well location, year of drilling, and type of wells were collected
in 2007. The information of well location is used to map their locations on the map
using GIS. Data and information were collected from about 70 wells and springs in
Rashda village by fieldwork. Also, through field checks in 2014 and 2016, a total of
25 government and local wells were investigated.
There are five types of wells; government well, local well, investment well, surface
spring, and the Roman spring.
(1) Government wells are generally deep wells and drilled by Ministry of Irrigation. There were 12 wells of this type in Rashda. (2) Local wells are usually less than
or equal to 85 m deep. This type of well is planned to last for 20 years. There were 29
wells of this type in Rashda. (3) Investment wells have a maximum depth of 500 m
and they are intended to last for 20–30 years. There were nine wells of this type in
Rashda. (4) Surface spring is as the name implies, has a depth less than 120 m. There
were about 34 surface springs of this type. The first one was constructed in 1998. (5)
Roman springs. They have a depth ranging from 85 to 100 m and they are exploited
by local farmers. There are eight springs of this type, but all of them have now dried
up.
Among these five types of wells, investment wells and surface springs have
increased since the end of 1990s.
3.2 Methods
Methods of analyzing the land use using satellite images followed 5 steps: (1) image
pre-processing and layer stacking, (2) image sub-setting, (3) image post processing,
1 See Chapter 12 on history of wells for more details.