使用QGIS開發地籍圖資加值應用外掛程式之實作驗證

Development and Validation of a QGIS Plugin for Extended Cadastral Data Applications

隨著地理資訊系統（GIS）技術的持續發展，開放原始碼且具跨平台特性的QGIS展現出高度可擴充性及友善介面，逐漸成為地籍圖資應用的新興工具。目前地籍測量之地籍圖如要轉至GIS系統，地政單位雖提供多種工具可轉出SHP檔或DXF檔，惟此類檔案轉入GIS系統常有失真情形。為因應地籍測量的實務需求，本研究旨在探討於QGIS環境中結合Python開發地籍外掛程式的可行性與成效，並聚焦於地籍圖資匯入、查詢、計算與分析等核心功能之應用。
本研究共開發3組QGIS外掛程式，合計14項功能模組。「cad_import外掛程式」負責匯入地籍圖與相關界址點、圖根點、相片、地籍調查表、土地所有權人及他項權利人等資料，並保留正確的圓弧曲線與地中地結構；「cad_calculate外掛程式」提供地號面積與公差計算、差異比對，以及整合的視覺化分析與查詢功能；「cad_survey外掛程式」則支援光線法MAC檔與現況點CNT格式資料之展繪、現況點至地籍線最短距離計算、利用數值高程模型（DEM）對觀測距離（OBS檔）進行歸化至平均海水面、網形平差成果圖繪製及三參數坐標轉換等相關功能。
研究結果顯示，透過客製化QGIS外掛程式可有效簡化地籍測量作業流程，突破傳統由政府機關開發之制式系統的限制，並展現GIS在地籍測量應用中的高度彈性與開發程式潛力。本研究不僅為地籍測量提供可行的開放原始碼解決方案，且具實務推廣及後續系統擴充之價值。

With the continuous development of Geographic Information Systems (GIS), the open-source and cross-platform QGIS has demonstrated high extensibility and a user-friendly interface, and is increasingly recognized as a tool for cadastral data applications. In current cadastral surveying practice, although land administration agencies provide tools to export cadastral maps as SHP or DXF files for GIS integration, these conversions often result in geometric distortions. To address these practical challenges, this study investigates the feasibility and applicability of developing custom Python-based cadastral plugins for QGIS, focusing on core functions such as data import, query, computation, and analysis.
Three QGIS plugins were developed, comprising 14 functional modules. The cad_import plugin manages the import of cadastral maps along with boundary points, control points, photographs, cadastral survey forms, landowners, and other rights holders, while preserving precise circular arcs and Enclave parcel (land-within-land) structures. The cad_calculate plugin provides parcel area and tolerance calculations, discrepancy comparison, and integrated visualization and query functions. The cad_survey plugin supports radiation method MAC files and surveyed points in CNT format, computes shortest distances from surveyed points to cadastral boundaries, reduces observed distances (OBS files) to mean sea level using Digital Elevation Models (DEM), generates network adjustment plots, and performs three-parameter coordinate transformations.
The results indicate that custom QGIS plugins can effectively streamline cadastral surveying workflows, overcome the limitations of conventional government-developed systems, and highlight the adaptability and extensibility of GIS in cadastral applications. This study not only provides a feasible open-source solution for cadastral surveying but also offers practical value for wider adoption and future system expansion.