透過幾何集合操作建立地價區段圖之程序探討

A Land Value Map Creation Procedure based on Geometric Set Operations

地價區段圖為政府對地籍資料進行估價之記錄成果，亦是土地稅收或徵收業務的重要參考依據。由於地價區段係由多邊形涵蓋評估為相同地價之相鄰宗地而構成，因此現行程序多半以在地籍圖上進行類似多邊形數化的方式完成數值化之動作，無論在時間、人力及精確度上均須縝密的考量。鑒於目前已有相當地籍資料為數值格式，若能有效利用已存在數值座標之優勢，應可有效縮減作業之時間。本文因此提出一個以宗地多邊形為基礎，透過多邊形幾何集合操作而建立地價區段圖的機制。整體架構透過宗地的分割及聚合來形成地價區段，而非逐點描繪地價區段的邊界線，我們相信無論在所需之人力時間及可達成之精確度上，所建議之架構對於現行作業程序均具有相當之參考價值。 Land value map is the recording of the government assessment on the value of cadastre parcels. It may also serve as an important reference to such government affairs as land tax and compensation. Since the coverage of a land value section can be regarded as a polygon covering a number of neighboring parcels with the same value, current procedures often rely on the digitization of the parcel boundary to determine its coverage. Careful consideration is necessary to reduce the time and work loading, as well as to ensure the digitized accuracy. Since a large portion of cadastre data is already in digital format, this digitization procedure can be improved if we can successfully take advantages of the already existed digital coordinates. We therefore propose a land value map creation procedure based on the parcel polygons and geometric set operations among polygons in this paper. The core idea lies on the idea to create land value section with the union and intersection of polygon parcels, rather than the detailed digitization of all the nodes one by one along the parcel boundary. No matter from the perspective of time, accuracy and work loading, the proposed mechanism can no doubt provide a new perspective to the reform of current procedures.

Land value map is the recording of the government assessment on the value of cadastre parcels. It may also serve as an important reference to such government affairs as land tax and compensation. Since the coverage of a land value section can be regarded as a polygon covering a number of neighboring parcels with the same value, current procedures often rely on the digitization of the parcel boundary to determine its coverage. Careful consideration is necessary to reduce the time and work loading, as well as to ensure the digitized accuracy. Since a large portion of cadastre data is already in digital format, this digitization procedure can be improved if we can successfully take advantages of the already existed digital coordinates. We therefore propose a land value map creation procedure based on the parcel polygons and geometric set operations among polygons in this paper. The core idea lies on the idea to create land value section with the union and intersection of polygon parcels, rather than the detailed digitization of all the nodes one by one along the parcel boundary. No matter from the perspective of time, accuracy and work loading, the proposed mechanism can no doubt provide a new perspective to the reform of current procedures.