Remote Sensing (Continued)

1. Use of Remote Sensing Data
in GIS
Geometric correction of satellite data
with reference to the projection
system of GIS database is pre-
requisite to use.

2. 1. Use of Classified data
Land cover map, vegetation maps or
forest type maps... can be derived from
remote sensing data through image
processing techniques. These maps can be
converted to the compatible formats of
GIS system and can be overlaid onto other
geographical data for spatial analyses and
monitoring environmental changes.

4. 2. Use of Image data
Remote sensing image can be
classified or analyzed with other existing
geographic information in order to obtain
a higher accuracy of classification.
Elevation map will be useful to
discriminate mangrove and other kind of
forests. Moreover, pine and hill evergreen
forests can be separated by combining
elevation map and image data.

5. 3. Satellite Orthophoto Maps (SOMs)
By using the digital elevation model, and ground control
points (GCPs), the aerial photos and satellite digital data
(digital formats) can be orthorectified. These image map are
called Orthophoto or Satellite Orthophoto maps (SOMs). The
X,Y,Z distortions of original image data is corrected.
These image map are used to overlay the political
boundaries, roads and railways. Such an image map can be
successfully used for visual interpretation.
Digital elevation model is used with remote sensing data
for shading corrections in mountainous areas can be made by
dividing Cos q (where q is angle between sun light and the
normal to the sloping surface).

6. 4.How we will move the RS data to GIS?
Remote Sensing data is almost always processed
and stored in raster data structures. When
working simultaneously with an image processing
system and a raster GIS, it is usually easy to
move data between the two. Once the remote
sensing data has been converted to a desired data
type, transferring this data to a raster GIS is
relatively easy. Most operational image
processing and raster GIS systems provide
mechanisms to read and write 8-bit-per pixel
raster arrays.

7. 4. How we will move the RS data to GIS?
More work is involved when transferring
raster data derived from image processing
system to a vector GIS. Continuos data
such as vegetation abundance, involves
extracting the contours of abundance
(often call isolines), the vectors are passed
to the GIS, along with labels to indicate
values associated with the contour lines.

8. 4. How we will move the RS data to GIS?
When working with discrete data such as land-use
derived from image processing techniques, the pixels that
form the boundaries of the areas are detected in order to
isolate the implicit homogeneous polygons in the derived
image. These are done by the skeletonization algorithms.
Then the boundary pixels are used to develop the vectors
surrounding the areas and attributes value and class
name are assigned to the bounded areas. The analyst will
often smooth the stair steps boundary between classes of
spatial objects to make the vector plots appear more
realistic. One should remember that the underlying data
may have been irreversibly changed. It is important to
understand that the conversion processes are limited by
the underlying data, in terms of precision and accuracy.

60. NOAAAVHRR FCC R2G1B1

61. NOAAAVHRR CH1 Red Band (0.58-0.68 micrometers)

62. NOAAAVHRR CH2 Near-Infrared Band (0.73 -1.10 micrometers)

63. NOAAAVHRR CH3 Intermediate Infrared Band (3.55 - 3.93 micrometers)

64. NOAAAVHRR CH4 Thermal Infrared Band (10.3 - 11.2 micrometers)

65. LANDSAT TM 432 1988 Oct 11

66. LANDSAT TM1 (0.45-0.52)

67. LANDSAT TM2 (0.53-0.61)

68. LANDSAT TM3 (0. 62-0.69)

69. LANDSAT TM4 (0.78-0.90)

70. LANDSAT TM5 (1.57 - 1.78)

71. LANDSAT TM6 (10.45 - 11.66)

72. LANDSAT TM7 (2.10 - 2.35)

73. TM321

74. TM532

75. 1984 Apr (MSS 431)

76. 1988 Oct (TM 432)

77. Murtiya forest, Sarlahi district, Nepal, 1978

78. Murtiya forest, Sarlahi district, Nepal, 1992

79. 1989 1992
1997
1986
1996
AP
AP
IRS1C
SPOT XS
ADEOS AVNIR M

80. Aerial photograph of Nagarjun Kakani aera
1989 Scale 1:25000 (approx.)

81. Notice the mass-movement (19 Km landslide)

82. Aerial photograph of Nagarjun Kakani area
1992 Scale 1:50000 (approx.)

83. SPOT XS 224/294 right look 22 Oct 1986

84. SPOT XS 224/294 left look 12 Dec 1986

85. Geological Map of Central Nepal;
DMG and UNDP; 1980