RSVG:Displaying Big Size Vector Map on Mobile Devices

Rsvg: 在行動裝置上顯示大型的向量地圖

肯莫茲(CONVOLBO MOISE)

指導教授 ： 鍾葉青

國立清華大學/電機資訊學院/資訊系統與應用研究所/碩士(2011年)

https://doi.org/10.6843/NTHU.2011.00687

摘要

在計算資源稀少的嵌入式硬體中，時常要面臨處理器能力、記憶體容量、傳輸頻寬等不足的問題。許多研究致力於解決這些限制，然而這必須創新的技術才能突破這些限制。對於行動裝置，除了資源限制，視窗的大小也必須考量。
顯示地圖資訊於行動裝置更是需要計算能力、記憶體與穩定的網路頻寬。基本便利，人們常用行動裝置來顯示地圖資訊，但是日積月累的地圖資訊逐漸複雜，因此載入、顯示完整的地圖於行動裝置是個困難。
本論文提出一個模型來顯示大型的向量地圖在行動裝置。在此模型中，我們提出一個概念，稱為Rsvg，首先在伺服端來建立地圖架構，然後經由事件驅動來顯示不同層級的地圖資訊於客戶端，此技術能減少資料從伺服端傳送到客戶端的等待時間。我們用全球網際網路組織的延展向量圖來評估模型的效益。我們解決了傳統顯示延展向量圖於行動裝置上的問題，從實驗數據中，使用先廣樹搜尋演算法與漸進式傳輸模型能擁有較好的效能。

關鍵字

延展向量圖 ； 層級式內容 ； 漸進式傳輸 ； 先廣式繪圖模型

並列摘要

In resource-constrained environment such as low-end-mobile, the challenges faced are mainly the memory and the processing capacities limitations, and the bandwidth rate. Many works tried to overcome them; yet, the need of intelligent applications is required to enhance the devices speed in many ways. For the display systems of the handheld devices, besides the listed constraints one needs to take in consideration the screen size.
Displaying Geographical Information (GIS) data such as Maps on these devices is very demanding in terms of processing and memory and requires a reliable strong bandwidth. On one hand, for convenience reason, mobile devices are commonly used for displaying GIS data. On the other hand, maps have become more complex so that it is challenging to load an entire map on de client and render at once.
To this end, this thesis presents a model for displaying big size vector maps on handheld devices. We propose in the server side, an Rsvg concept through a data structure for maps organization. In the client side, we present an event-driven Level Of Details (LOD) for the defined data structure and a reduction of the waiting time while a zooming event required downloading from the server. This model is then applied in the evaluation of the Scalable Vector Graphics (SVG) of the World Wide Web Consortium (W3C). While rendering big files in the traditional SVG display is impossible in mobile client, Rsvg experiments demonstrated better results through the progressive transmission, based on the breadth first tree traversal algorithm.

參考文獻

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[16] C. Peng, "SCALABLE VECTOR GRAPHICS (SVG)," Tik-111.590 Research Seminar on Interactive Digital Media, 2000, 2000.

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