數值化圖籍於套疊平面精度之研究

Abstract

在地理資訊系統中，其空間資料格式分為向量式資料及網格式資料兩種，向量式資料雖然能夠精確的表示其地理位置，但是在地物、地貌的表現上卻沒有網格式資料來的豐富，若能夠以網格式資料為背景套疊向量式資料便能充分表現其效果及內容。但是其空間資料的誤差不僅只出現在資料本身的誤差，其誤差都可能隨著資料處理的過程傳播至最後圖層，進而影響到成果資料的品質。因此要應用地理資訊系統作為決策分析的工具，就必須對於空間資料的誤差來源及所有對資料的操作過程，建立適當的、正確的分析模式。 本研究應用數值化向量式地籍圖及數值影像像片基本圖來進行圖層套疊分析，然而必須先分析數值影像資料及數化地籍圖向量式資料之誤差來源及數化精度；但因數值化地籍圖，各類地籍圖間沒有一個統一的坐標系統，導致仍存在坐標系統及圖幅接邊的問題。本研究應用橡皮伸張法及地籍圖接邊平差法的方法來進行地籍圖接邊處理，與現場實測資料進行比對，期望能找出應用何種接邊處理的方法其精度較佳。而進行圖層套疊分析時，空間資料之誤差可能隨著資料處理的過程傳播至最後結果，影響到成果資料的品質，因此本文應用誤差傳播定律，以瞭解空間誤差如何經由處理過程傳播至最後成果來得到套疊之後精度，期望藉由誤差傳播模式，能建立圖層套疊的位置精度評估模式，確保套疊資料品質。 實驗結果發現：（1）應用橡皮伸張法及地籍圖接邊平差法的方法來進行地籍圖接邊處理並且與現場實測資料進行比對，其兩者之方法誤差值滿足地籍測量實施規則中，市地界址點誤差應小於6公分的規範。（2）藉由誤差傳播定律，分析出套疊之精度與現場實測資料進行套疊比對兩者之差異非常小，所以可以利用誤差傳播定律得知圖層套疊之間的精度，建立圖層套疊模式將套疊過程產生的誤差予以量化，確保套疊資料品質，使用者才能夠根據其資料，作出適當的使用、評估、決策。

Within the Geographic Information Systems, the spatial Data formats include Vector Data and Raster Data. Although Vector Data can accurately represent the geographic position, the terrain, representative have not been finished as emplaned to Raster Data. If spatial Data are on the background of Raster, the content and effectives can be expressed clearer. Error has not only appeared in the data presided, it also flows down the process of information to the end result with the influence of result quality. Therefore, to apply geographic information systems as decision analysis tool, on appropriate, correct analysis model for error of spatial data souring and all data control process have to established. This research applies to Digital Vector Cadastral Map and Digital Air Photo Map for mapping overlay, but the error of souring and digital precision from Digital Cadastral Map and digital photo map have to be analyzed. Since digital map and all types of map there is no standard coordinate system and there is edge matching problem. Rubber sheeting and adjustment of cadastral map edge matching one method to handle edge matching in this research. Field testing information are compared to expect to find out which is the more precise method for edge matching. As map overlaying analysis, the error of spatial data will follow the data handling process down the stream to the final result and affect the quality of result data, therefore, this research applies "error propagation principle" in order to understand how error of spatial data flows down the stream to end result after map overlay, hopefully through the error propagation model to establish positional accuracy assessment model of map overlay to assure map overlay data quality. Results of experience illustrate: 1) apply "rubber sheeting" and adjustment of cadastral map edge matching methods for cadastral map edge matching and filed testing information for comparison, the error value satisfies cadastral surveying operation regulation, district boundary error is smaller than 6 cm as regulated. 2) Through the error propagation principle, map overlay accuracy is analyzed and compared with field testing data map overlay with very small difference, therefore, error propagation principle can be used to trace accuracy of map overlay, to establish quantified error for the process of map overlay model to assure quality of map overlay so as user can use the data for appropriate use, evaluation and decision.