Abdalla Fadl Elmula, Isam Eldin
2. Materials and Methods:
(i) Two sets of landsat imagery were interpreted. The first data set was thematic mapper (TM) imagery composed of a
false color scene and a true color scene (mosaic). The specifications of this set were explained in table 1 below.
Scene No. | Path/ Acquisition date Band combination | Color Remark
Row composite
1 175/51 03.11.1985 2.3.4 B,G,R False color
2 175/52 06.11.1986 2.4.7 B.G.R True color
Table 1: Specifications of the TM imagery set
(ii) The second set of landsat data is a multispectral scanner (MSS) imagery acquired in Nov. 1972 in black and
white. The images were of separate bands; those were band 4, band 5, and band 7.
(iii) The third information data is a land use/land cover map, produced by the Sudan Survey Department (SSD) in
cooperation with the Hunting Technical Service (HTS) at the SSD laboratories.
(iv) The training sites of the two sets of images were interpreted and delineated, and the land use/land cover strata
were labeled after the field checks.
(v) The strata were then digitized using the GIS, (ARC/INFO) software.
(vi) For the MSS data, bands 4 (green), and band 5 (red) are usually best for delineating cultural features such as
urban areas, roads, new subdivisions, gravel pits, and quarries (Lillesand, and Kiefer, 1979). Therefore it was
found very easy to interpret the vegetational features versus the cultivated areas.
3. Results:
3.1 Interpretation of landsat TM images:
In the first and second training sites (Sa'ata Ezzarqa, and Hillat Sa'id) which lie in the false color scene, the areas of the
healthy vegetation were very clear, they are represented by the red color. This reflection is coming from the near
infrared (NIR) band 4. The chlorophyll pigment is highly reflected by the NIR band 4. The cultivated areas appeared in
a pale brown color characterized by their rectangular shapes. The fallow areas were shown on light tones in between the
farms. The damaged areas were highly reflected by the visible spectral (vs) band 3 (the chlorophyll absorption band).
This reflection depends on the degree of the death and damage. Therefore it is characterized by its green color where the
vegetation is severely damaged and appears dark green where the vegetation is slightly damaged. The damaged
vegetation has on the reverse lower reflection on the NIR band 4. The bare areas (sand) were shown by the yellow
color. This reflection is coming from the composition of the visible spectral (vs) band 3 (green), and the NIR band 4
(red), see sample image-1. The final land cover classification of these two training sites is shown on maps. These maps
are produced using the facilities of the GIS (Arc/Info software), see sample map-1. The third and fourth training sites
(Abu Ku' and Addibeibat area), lie in both the two scenes (the false color one and the true color). In the true color scene,
the healthy vegetation is represented by the green color. This reflection is coming from the NIR TMA (green), and this
is found along the wadies and in the depressions. The cultivated areas appeared in pinkish color and characterized by
their rectangular shapes. This color is coming from the composition of the blue reflection that is coming from the (vs)
band TM2, and the red reflection coming from the middle infra red (MIR) band TM7. The mountainous area in the
south of (Addibeibat subset) appeared in (pinkish) color. This color is coming from the reflection of the rock in the MIR
band TM7 (red), combined with the reflection of the scattered vegetation in the (vs) band TM2 (blue). This
mountainous land is part of the famous Nubian Mountain.
Generally the interpretation and field checks showed that the land use in the study area is as follows:
1- Cultivated agricultural areas.
2- Forestry/ Fuel wood.
3- Populated.
32 Interpretation of Landsat MSS for Land use/ land cover:
The interpretation of the MSS images acquired in 1972 showed that the land cover of the area is composed of healthy
vegetation (scattered in some areas and dense in the others), and cultivated areas in addition to the populated areas. The
villages and towns represent the populated areas. These towns appear as dark tone masses and characterized by the light
tone roads that are coming towards them. The vegetated areas are clearly identified in the (NIR) band MSS 5. These are
characterized by their dark Grey tone.
3.3 Maps of the Aerial Photographs:
14 International Archives of Photogrammetry and Remote Sensing. Vol. XXXIII, Part B7. Amsterdam 2000.
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