A GIS Assisted Knowledge-Based Approach for Military Operations


Study area
The KB presented here has been designed keeping in mind its effective use in the western borders of our country. In the western region, the general terrain conditions are plain with the soil type varying from desert sands of Rajasthan to the marshy areas of Gujarat. The landscape in this region is interspersed with rivers and canals.

However, due to the security restrictions in use of topographical sheets of the border areas, an area having somewhat similar ground conditions has been selected here to test the knowledge-based approach developed. The area lies south of Saharanpur city, UP, between Latitude 29°45’ to 29°50’ and Longitude 77°30’ to 77°35’. Survey of India (SOI) map sheet 53 G/9 having a scale of 1:50,000 has been used. The area covered is approximately 8 Km by 8 Km. This area has one major river Hindan flowing from north to south and few canal systems as shown in Fig 1.

Fig. 1 Topographical map of study area selected

GIS Data Layers
The rules to be formed are based upon the spatial information about the terrain as desired by a particular military operation. A number of spatial raster data layers are prepared. The data for the study area has primarily been collected from the topographical map as above. However, due to non-availability of certain information, some hypothetical data has also used for the preparation of layers. Following data layers have been prepared by on-screen digitizing the scanned topographic map in ERDAS Imagine,
  1. Water Bodies
    In the study area one major river, River Hindan, is flowing from north to south with a network of canals, to the north west of the area and some small lakes around villages. Thus, three categories of water bodies are considered as rivers, canals and lakes with their raster values assigned as 1, 2 and 3 respectively (Fig. 2).


    Fig. 2 Thematic layer of water bodies

  2. Road network
    Existing roads and tracks are an important aspect as it ensures the smooth movement of both fighting columns and logistical supplies. The area has a good network of roads and tracks both along the river and perpendicular to it. The roads and tracks are therefore the automatic choice for the categories in roads layer and are assigned a raster value of 1 and 2 respectively (Fig. 3).


    Fig. 3 Thematic layer of road network

  3. Power Lines
    Existence of power lines is an important factor while deciding the location of helipads. Hence, power lines have also been digitised and assigned a raster value as 1 and rest of the area as 0 where no power lines exist (Fig. 4).


    Fig. 4 Thematic layer of power lines

  4. Slope Map
    The area is in general flat with heights varying from 252 m to 267 m. Only one contour at 20 m interval passes in the vicinity of the area. Therefore, spot heights and benchmarks available on the topographical sheet have also been digitized to generate a Digital Elevation Model DEM. 3D surfacing tool of ERDAS Imagine has been used to generate a raster DEM from the digitized contour and the spot heights (Fig. 5). From this DEM, a slope map has been prepared showing four categories as, no slope (0% slope), plain (slopes less than 5 percent), moderate (slopes between 5 to 10 percent) and steep (slopes greater than 10 percent) (Fig. 6).


    Fig. 5 Raster DEM of study area
    Fig. 6 Thematic layer of slopes

  5. Land use land cover map
    IRS-LISS III data has been used for classification of various land use and land cover of the area. Five land use land cover categories namely built-up areas, forests, rivers, canals and cultivated areas have been selected and given raster values as 1, 2, 3, 4, and 5 respectively (Fig. 7).


    Fig. 7 Thematic layer of land use

In addition to the above data layers, two more data layers have been prepared based upon the hypothetical data,
  1. Soil map
    Soil conditions play an important part in the process of site selection for various military tasks like bridging, helipad location etc. The factors like bearing capacity and the soil moisture are critical for operations like bridging. Approach to site and area near a bridge must be able to take on heavy vehicular traffic. Due to lack of authentic soil map of the area, a hypothetical soil data has been generated and is classified into three categories namely sand, silt and clay with their raster values as 1, 2 and 3 respectively (Fig. 8).


    Fig. 8 Thematic layer of soil types


  2. Water depth
    Wet Bridges are built using pontoons having decked girders, which float on water. Hence there is need for minimum water depth, which is generally kept as 1m. In absence of authentic data, hypothetical water depth data for the river in the study area has been generated and divided into two broad categories as adequate or inadequate with raster values assigned as 1 and 2 respectively (Fig. 9).


    Fig. 9 Thematic layer of water depth



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