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GIS SPATIAL ANALYSIS FOR DIGITAL ELEVATION MODEL _DEM_ APPLICATION

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GIS SPATIAL ANALYSIS FOR DIGITAL ELEVATION MODEL _DEM_ APPLICATION Powered By Docstoc
					  International Journal of Civil Engineering OF CIVIL ENGINEERING AND
  INTERNATIONAL JOURNAL and Technology (IJCIET), ISSN 0976 – 6308
  (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME
                            TECHNOLOGY (IJCIET)
ISSN 0976 – 6308 (Print)
ISSN 0976 – 6316(Online)
Volume 4, Issue 2, March - April (2013), pp. 96-103
                                                                              IJCIET
© IAEME: www.iaeme.com/ijciet.asp
Journal Impact Factor (2013): 5.3277 (Calculated by GISI)                  © IAEME
www.jifactor.com




   GIS SPATIAL ANALYSIS FOR DIGITAL ELEVATION MODEL (DEM)
                         APPLICATION

                                    Dr. Tarek A.E., El-Damaty
                            Faculty of Engineering – Banha University


   ABSTRACT
           The study area of this paper is Alsukhna city; which located along the Cairo –
   Hurgada highway. The problem arraised when the Egyptian authority needed to know the
   actual amount of cutting and filling in the mountains exist in the city during the project of
   city construction for environmental assessment purposes.
           Two digital terrain models (DEM) have been careated; one was before the city project
   construction and the other one was after the city project construction by using extensive
   studies, satellite images, field visits, field mesurements and topographic maps. GIS spatial
   analysis was applayed to compare and analysis the two DEMs results.
           By analyzing the two DEMs; it was found that: the total amount volume of cutting
   from mountain is 116 405 841 m3 and the the total amount volume of filling is 113 612 511
   m3 with percentage of 98% of using the cut material in filling process.
           It could be concluded that the cut and fill process that had been done were very
   important in order to protect the project area from the rainfall risks and mountain collapse.

   INTRODUCTION
           Geographic Information System (GIS) is a computer-based system that provides the
   following four sets of capabilities to handle geo-referenced data: input, data management
   (data storage, maintenance and retrieval), manipulation and analysis, and output. GIS allow
   interpreting and visualizing data in many ways that reveal relationships, patterns and trends in
   form of maps, globes, reports and charts.
           The main objectives of this study are to investigate the actual situation of Alsukhna
   city project and to get the amount and places of cutting and filling that had been done in the
   mountain at the project area. This paper will based on extensive studies using satellite images
   and field visits and topographic maps that contain the geographic features produced by
   Surveying in the ground prior to the commencement of the project and the existing
   topography of the project in addition to a series of scientific reports.

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    International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
    (Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

    MATERIALS AND METHODS
             The collected data consist of topographic maps that contain the geographic features
    produced by Survey Authority and Military Survey scale 1:2500 (1990), field survey using Total
    station (XYZ), satellite images, and statistical data.
             AutoCAD, Arc-GIS, and Erdas Imagine software are used in data entry and analysis, in
    addition to land-use/land-cover data are checked in the field by using GPS and Total station to
    update and upgrade the topographic map. These data are collected from different sources for
    verification. The procedures followed to build a GIS for the project (Porto El-Sokhna) and make
    it ready for analysis are: (1) data capture, (2) data preparation, (3) data extraction, (4) data
    integration. These steps are followed to develop the required GIS based on various types of data
    available from multiple sources.
             A vector - based GIS was developed by digitizing the available maps, construct topology
    of various layers, editing errors, reconstruct topology, and adding attributes. The GIS includes
    layers of land uses, roads, elevations, census tracts and population characteristics. A LANDSAT-
    MSS satellite images are used to obtain data on the extent of urban areas in. The satellite image is
    rectified to the same projection system of the base map and classified using maximum likelihood
    technique. The classified images are integrated within the multi-layered GIS.
    METHODOLOGY
            The technique used in this study is based on building up and analysis of a geographical
    information system layers. The main steps involved in building a geographical information
    system include; data collection, input spatial data, edit & create topology, input attribute data and
    data analysis.

•   A first step includes the technical measuring of the ground levels and borders by using different
    surveying instruments, such as total station and GPS.
•   A second step includes the data processing of the measurements by using different surveying
    software.
•   A third step includes the technical conversion from file format DXF and/or DWG to GIS software
    to prepare a georeferenced geodatabase and classify it as layers.
•   From the digital data it could be build up a model of 3D topography which is called Digital
    Elevation Model (DEM); that gives more easier realization and interpretation after and before
    construction. The data file of DEM before construction was as following:
    Vector data information; ESRI description; Vertical; Minimumelevation:0.000000; Maximum
    elevation: 286.000000; Node Geometry Node; Topology: TRUE; Feature count: 45766; Spatial
    Index:TRUE; Linear referencing: FALSE. Geometry type: Edge; Topology: TRUE; Feature
    count: 274299; Spatial Index: TRUE; Linear referencing: FALSE; SDTS description; Feature
    class: SDTS feature type, feature count; Triangle: Ring composed of chains, 91433; Node: Node,
    planar graph, 45766;Edge: Link, 274299.
    The data file of DEM before construction was as following:
    Vector data information; ESRI description; Vertical; Minimum elevation: 0.000000; Maximum
    elevation: 286.000000; Triangle; Geometry type: Triangle; Topology: TRUE;
    Feature count: 571074; Spatial Index: TRUE; Linear referencing: FALSE; Geometry type: Node;
    Topology: TRUE; Feature count: 285556; Spatial Index: TRUE; Linear referencing: FALSE;
    Geometry type: Edge; Topology: TRUE; Feature count: 1713222; Spatial Index: TRUE; Linear
    referencing: FALSE; SDTS description; Feature class: SDTS; feature type; feature count;
    Triangle: Ring composed of chains, 571074; Node: Node, planar graph, 285556; Edge: Link,
    1713222.

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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

RESULTS AND DISCUSSIONS

Using the above data files; two digital eleation models have been created. Figures (1; 2)
illustrate the DEM results.




                 Figure (1): Digital Elevation Model before construction




                 Figure (2): Digital Elevation Model after construction


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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

        A Slope map is important in identifying constraints and evaluating potential
environmental impacts related to landform alteration. Major constraints can be tied to
grades/inclinations that are either too steep (to reasonably construct structures, roads, etc.) or
too gentle (for playfields, etc.) Major impacts related to inclination include erosion/loss of
soil/non-point source pollution and slope failure (linked to weak rock, soils with low bearing
capacity, steep slopes, etc.) Coupled with aerial photographs, slope maps are excellent tools
to look for potential erosion areas, drainage patterns, landform and soil patterns, land use
suitability, etc. Figures (3; 4) illustrate the slope map before and after construction.




                            Figure (3): Slope map before construction




                          Figure (4): Slope map after construction

        Contour maps are a useful way to visualize the spatial relationships among data and
the spatial distribution of data values, which represent the locations that have the same
altitude Fig.(5; 6) show the contour map before and after construction.


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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME




                     Figure (5): Contour map before construction




                      Figure (6): Contour map after construction




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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

The volumes of work that had been done in the project could be determined and compared
with the current situation from the two surfaces of land before and after the project; also we
identified the zones of cut and fill into GIS Analysis to produce the TIN- Difference and
profiles. Figure (7) illustrates the TIN differences.




    Figure (7): TIN- Difference between the two surfaces (before and after the proect)

Eight profiles have been selected randomly to cover the all site to display the difference
between the two surfaces (before and after construction). Figure (8) shows the eight profiles
and Figures (9; 10) show the profile number five.




                 Figure (8): The 8 profiles that distributed in the all site


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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME




                     Figure (9): Profile number 5 before construction




                     Figure (10): Profile number 5 after construction

CONCLUSIONS

        The project is located on the area of El-Galala mountain; which its height is reaching
1200 m, with a total area of 1 303 324 m2. The height in the project area is ranging between 0
and 286 m. A number of 109 points are chosen as observation points to cover the all project
area for height comparison.
        By analyzing the satellite image and comparing the heights before construction (using
the topographic contour map) and after construction (using actual field measurements);
through the creation of two digital elevation models; we found that: the total amount volume
of cutting from mountain is 116 405 841 m3 and the total amount volume of filling is 113
612 511 m3 with percentage of 98% of using the cut material in filling.
        The average height of the project area after finshing the proect is remaining 82 m as
the same height before starting the project.
        The cut and fill process that had been done were very important in order to protect the
project area from the rainfall risks and mountain collapse.

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International Journal of Civil Engineering and Technology (IJCIET), ISSN 0976 – 6308
(Print), ISSN 0976 – 6316(Online) Volume 4, Issue 2, March - April (2013), © IAEME

REFERENCES

   1. Egyptian Military Survey (1985): Topographic Sheets, scale 1:100,000, Cairo Egypt,
       34 sheets.
   2. El-Shazly, E. M; M. A. Abdel-Hady and M.L.El-Rakaiby (1991): Drainage
       megabasins in Egypt. Bull. Soc. Georg. d`Egypt, Tome LXIV, pp 45-58.
   3. Fairhead, J. D. and Girdler, R. W. (1970): The seismicity of the Red Sea, Gulf of
       Aden and Afar triangle. Phil. Trans. Roy. Soc. London, 267 (A), pp 49-74.
   4. Garfunkel, Z. and Bartov, Y. (1977): The tectonics of the Suez rift. Bull. Geol. Surv.
       Isr. 71, pp1-48.
   5. Linsley, R. K, J. B. Franzini, D. L. Freyberg and G. Tchobanoglous, (1992): Water
       resources engineering. McGraw Hill, New York, 4th edition, 841 p.
   6. McKenzie, D. P, Davies, D. and Molnar, P. (1970): Plate tectonics of the Red Sea and
       east Africa. Nature 226, pp.243-248.
   7. Strahler, A. N. (1952): Hypsometric (area altitude) analysis of erosional topography.
       Geol. Soc. Am. Bull. 63, pp 1117-1142.
   8. ESRI. (2001).Getting to know Arc GIS. Redland, California: ESRI Inc.
   9. Ian, Heywood,and other(1999), An Introduction to Geographical Information Systems
       New York.
   10. Dr. Tarek Abd El-Hamied Hassen El-Damaty, “The Role of Kalman Filter in
       Improving the Accuracy of GPS Kinematic Technique” International Journal of Civil
       Engineering & Technology (IJCIET), Volume 4, Issue 2, 2013, pp. 49 - 57,
       ISSN Print: 0976 – 6308, ISSN Online: 0976 – 6316.




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