Single and Multiple Thread Programming for Geo-visualization by Using WebGL with Web Workers

—So far, various web elements and web environments have contributed to Web GIS as alternative technologies of existing GIS technologies. Map and web services such as Google Maps and Google Earth appeared as main components of web GIS and they still used as favorite services by general people who don't even know about GIS well. However, there is limit on visualizing raster data on web browser because of limit of raster data as image. Most geo-browsers like Google Earth still handle raster data as image and this causes limitation of expressiveness because delicate expression of raster on Google Earth is impossible. So WebGL which supports 3d graphic library is suggested as an alternative technology and diverse studies suggest WebGL application as result of them. But if we use WebGL as client, huge size of raster data causes overload during execution procedure. To secure operational efficiency on web environments, concurrent process is needed to use each core effectively. In this paper, to develop the method for visualizing raster by WebGL, we designed the processing which displays raster data on a Web browser as it preprocesses them by building shaders and dividing data. And to check efficiency of concurrent environment, we applied single and concurrent thread to the visualizing process and performed benchmarking between single and concurrent environments by comparing the visualizing processes in different environment variables.