1. MapWindow Plug-in of GRM Model Using Open Source Software It was possible to implement all the functions necessary to develop GRM modeling system and pre and post processing tools by using open source software. Can calibrate the GRM model and analyze the uncertainties easily using PEST The compatibility was improved by using general GIS data formats (shape file, GeoTIFF, ESRI ASCII). The results can contribute to the wide spread of GRM model and physically based rainfall-runoff modeling. The experiences can present useful information in developing distributed runoff modeling system using open source software. Original GRM (Grid based Rainfall-runoff Model) model runs in HyGIS (Hydro Geographic Information System), commercial GIS software. It is needed to buy commercial GIS to use GRM. The objective of this study is to develop a MapWindow GIS, an open source software, plug-in of GRM model (MW-GRM). Develop pre and post processing tools and auto calibration function using open source softwares like GDAL, PEST, etc. FOSS4G SEOUL 2015 Yunseok, Choi* / Youngho, Je** / Kyungtak, Kim* / Joohun, Kim* * Korea Institute of Civil Engineering and Building Technology, ** HermeSys Co., Ltd. Introduction Softwares Developing GRM Plug-in Using OSS Conclusions GRM(Grid based Rainfall-runoff Model) - Physically based rainfall-runoff model - Use kinematic wave model, Green-Ampt model - Calculate overland flow, channel flow, subsurface flow, baseflow, and flow control facilities effects - Written in Visual Basic.NET System Env. : Windows 7 64bit Applied Software : MS Visual Studio 2013 express, MapWindow 4.8.8, GDAL, PEST How to use : Execute MW-GRM menus Making input data and pre-processing - Make input rater layers (watershed, flow direction, flow accumulation, stream, and slope) from DEM by using GIS softwares - Convert the input layer format to GeoTiFF or ESRI ASCII - Convert time series raster layer format, clipping, resampling, etc. by using GRM Tools, included in the MW-GRM Model calibration using PEST - Select target parameters, set the observed data, and select single or parallel pest process by using the uncertainty analysis GUI, included in the MW-GRM - Set PEST parameters by modifying the default values - Check and revise PEST input files (pcf, pif, ptf, rmf, etc.) - Execute single or parallel PEST using the GUI GDAL(Geospatial Data Abstraction Library) - Open source software for raster and vector data translation - Provide programming libraries and console execution files for developing applications - Support various GIS data type (GeoTIFF, Erdas Imagine, ASCII, SHP, KML, etc.) PEST - Open source software for model parameters estimation and uncertainty analysis - Support single and parallel execution processes - This study developed an GUI for making PEST input files and running PEST automatically connected with GRM model. MapWindow - Open source GIS software developed using MS.NET for Windows (using 4.8.8) - Can apply C#, VB.NET, VB, VC++, Delphi, etc. - Support plug-in type extensions - Support many GIS data types (SHP, DXF, DGN, TIFF, JPG, GIF, etc.) <Time series layers processing using GDAL> <Uncertainty analysis GUI using PEST> <Model calibration using parallel PEST (runs 8 slaves)> <Dynamic display of modeling results>