Application Programmer Interface (API) In GIS For Water Resources ModelingR. Sivakumar Department of Remote Sensing, Birla Institute of Technology Mesra, Ranchi-835215 skm_ram@yahoo.com V.H. Vinod Kumar Department of Remote Sensing, Birla Institute of Technology Mesra, Ranchi-835215 vinod_win@hotmail.com ABSTRACT An important trend in computing systems architecture is the development of a common graphical user interface (GUI) to all application software’s. Development of the GUI is the use of standard application programmer interface (APIs). GIS developers normally design their software to meet the needs of the largest possible number of users. The best way to get maximum use of a GIS is to customize the software. GIS products may be customized using standard APIs such as visual basics and visual c programming environment. Using graphical APIs even GIS end users will be able to customize their applications with little training. In this paper aim is to develop an application programmer interface (APIs) to analyze the water resources related data to develop simulation model through integrated Geoinformatics techniques using visual basic and ODE environment. These tools are used to develop interactive environment regarding the Editing and Ground water modeling. The test site Torvarcha watershed situated on the coromendal coast of Pondicherry region is considered for the ground water simulation modeling using the APIs. Introduction An important trend in computing systems architecture is the development of a common graphical user interface (GUI) to all application software’s. GUI such as windows environment is now a standard feature for the leading GIS software packages. It also reduces training time by presenting the user with intuitive windows, icons, dialog box, and other helps. Development of the GUI is the use of standard application programmer interface (APIs). GIS developers normally design their software to meet the needs of the largest possible number of users. So GIS package will not provide optimal use of the technology unless it is customized for a particular user needs (George, 2001). The best way to get maximum use of a GIS is to customize the software. GIS products may be customized using standard APIs such as visual basics and visual c programming environment. Using graphical APIs even GIS end users will be able to customize their applications with little training. The end users that do not use GIS on a consistent basis they rarely need sophisticated analytical tools. Rather they primarily need to view and query graphic and attribute database (Narayan, 1999). In the present paper API is developed using ODE environment and visual basic for the water resources planning with special reference to ground water simulation modeling. Objective The objective of the research is to develop an application programmer interface (APIs) to analyze the water resources data to develop simulation model through integrated Geoinformatics techniques using visual basic and ODE environment. Tools Used to develop APIs Arc/Info Open Development Environment (ODE) on Windows NT, Arc Macro Language (AML) Script, Visual Studios About Application Programmer Interface (APIs) The Arc/ Info Open Development Environment provide to create a new visual environment. The ODE environment support ActiveX Controls, Visual Basic, Visual C++, also incorporate Arc Macro Language (AML) Scripts in the ODE environment to generate output ASCII files. These tools are used to develop interactive environment regarding the Editing and Ground water modeling (Fig:1). In editing user interface vector layers operations like, open coverage with back coverage, create new coverage, managing the coverage’s like copy, delete, rename, topology building, basic tools like zooming potions, pan across the map extent display coverage like arc, polygon, node, label, tic, view list of tables, add features to the existing edit coverage, feature selection tools, geo-processing like union and clip coverage etc. In Ground Water Modeling contains analysis section such as to start with the required maps for the analysis like watershed boundary, drainage network, landuse / land cover, geomorphology, soil map, Lithology etc., The input map includes well location map was prepared from the available reports and field collected information along with water level contour map is generated. Parameter zonal maps like Transmissivity, Rainfall, Recharge Factor, Specific Yield, Sub-watershed, are the basic thematic database is required for the ground water simulation modeling. Analysis and Discussion The spatial and non-spatial data was integrated in GIS environment to develop the simulation model. The simulation model was developed to discretize the study area into M number of linear triangular elements and N nodes, it requires watershed boundary, drainage or river boundary, randomly points are placed inside the watershed boundary to generate FE mesh coverage, FE node coverage and node connectivity ASCII file (Fig:2). The finite element mesh and well location data are interpolated to generate the ASCII file which will give the information regarding the well locations with in the FE mesh watershed (Fig:2). ASCII file containing the information of nodal water level using FE nodal coverage, water level contour coverage, watershed boundary, stream coverage with cell size of the grid in meters. ASCII file containing information about Ground Water Draft Zone map and FE Mesh cover is integrated to generate number of FE elements fall under the Specified Ground water draft zones. Transmissivity Zone map and FE Mesh cover is integrated to generate the ASCII file containing the information about the FEM element fall under the Specified Transmissivity Zones. Specific Yield Zone cover and FEM cover is integrated to generate output file containing number of FEM Element fall under the Specified Specific Yield Zone. Recharge Factor Zone cover and FEM cover is integrated to generate the ASCII file giving the information on number of FEM elements fall under the specified Recharge Factor Zone. Zonal map and FEM cover of watershed is integrated to Generate output file giving the information about number of Finite Element falls under the zoned Region. All the above generated ASCII files required for the FORTRAN / C / C++ Programme for Ground Water Simulation modeling. The final result gives the simulation for ground water balance components.  The test site Torvarcha watershed situated on the coromendal coast of Pondicherry region is considered for the ground water simulation modeling (vinod & sivakumar, 2005). The Torvarcha watershed region is discretized using the finite element mesh formulation into linear triangular elements. The watershed region contains 609 elements and 376 nodes which forms a complete network for analysis. For this, Ground water simulation modeling tool is used to generate the node connectivity data. These data are used as one input file for the FORTRAN ground water simulation. The study region is divided in to two zones on the basis of geomorphological and soil/lithological parameters for the delineation of transmissivity and specific yield zones. The geomorphological features namely alluvial plain, Flood plain and Coastal Plain are taken for transmissivity weightage analysis. Similarly soil/lithological features consists of un-consolidated Sediments which cover three fourth of area is considered for specific yield analysis. To generate the INPUT parameters for the Programme, the data on observation well, specific yield, transmissivity value, Rainfall recharge value, groundwater draft and initial water level at nodes were given. The above generated estimated parameters are used as input for simulation program. The data includes number of blocks, draft zone, rainfall zone, and number of elements, number of nodes, number of days of simulation year, time interval in days, transmissivity, specific yield, recharge value, ground water draft and monthly rainfall. The simulation program generates the output namely yearly and season wise water balance quantity and water level change in the observation wells. Hence the tool developed under ODE environment can be modified for other watershed as per the need by adding some more parameters. Further it can also be extended for salt water intrusion modeling. REFERENCES
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