Online 3D terrain visualization of GIS data: A comparison between three different web servers

Geographical Information Systems (GIS) and three dimensional (3D) World Wide Web (WWW) applications usage are on the rise.The demand for online 3D terrain visualization for GIS data has increased.Current users demand for more complex data which have higher accuracy and realism. This is aided by the emergence of geo-browsers in the market which provide free service and also cater for the commercialized market.Other new technology driving the market is the use of software such as CityGML, Virtual Reality Markup Language (VRML)/ Entensive 3D (X3D),geoVRML, and Keyhole Markup Language (KML). These technologies also play an important role for this new era of online 3D terrain visualization.The aim of this paper is to implement the online 3D terrain visualization for GIS data by using VRML technology and launching the system into three different web servers.The data used for this system are contour data and high resolution satellite image (QUICKBIRD) for Universiti Putra Malaysia (UPM) area. Testing was done only for satellite image overlaid to 3D terrain data.The web servers used in this experiment were the Spatial Research Group Server in UPM, Universiti Utara Malaysia (UUM) web server, and ruzinoor.my web server.The comparison was based on the performance of web servers in terms of accessibility, uploading time, CPU usage, frame rate per second (fps), and number of users. The results from this experiment will be of help and guidance to the developers in finding the right web servers for the best performance on implementing online 3D terrain visualization for GIS data

An Analytical Approach to Performance Analysis of an Asynchronous Web Server

Concurrency can be implemented in a Web server using synchronous and asynchronous mechanisms provided by the underlying operating system. Compared to the synchronous mechanisms, asynchronous mechanisms are attractive because they provide the benefit of concurrency while alleviating much of the overhead and complexity of multi-threading. The Proactor pattern in middleware, which effectively encapsulates the asynchronous mechanisms provided by an operating system, can be used to implement a high performance Web server. The performance expectations imposed on a Web server make it necessary to analyze its performance prior to deployment. While performance of a server can be measured after implementation, design-time performance analysis, conducted early in the life cycle, can also enable informed configuration and provisioning choices. A model-based approach can be used for such design-time performance analysis. In this paper we present a queuing model of an asynchronous Web server implemented using the Proactor pattern. We discuss the implementation of the queuing model using the Stochastic Reward Net (SRN) modeling paradigm. A model decomposition strategy along with its SRN implementation to enable the application of the model to practical Web servers is then described. We demonstrate the use of the model to guide key provisioning and configuration decisions using several examples. 1 Introduction an

An Analytical Approach to Performance Analysis of an Asynchronous Web Server

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