WEKO3
アイテム
山岳林地域における地形解析に関する基礎的研究
https://doi.org/10.18999/bulnuf.11.39
https://doi.org/10.18999/bulnuf.11.390f634a08-bc95-44d7-96d5-271136355a07
名前 / ファイル | ライセンス | アクション |
---|---|---|
bulnuf_11_39.pdf (16.1 MB)
|
|
Item type | 紀要論文 / Departmental Bulletin Paper(1) | |||||
---|---|---|---|---|---|---|
公開日 | 2007-08-23 | |||||
タイトル | ||||||
タイトル | 山岳林地域における地形解析に関する基礎的研究 | |||||
言語 | ja | |||||
その他のタイトル | ||||||
その他のタイトル | Fundamental studies on the terrain analysis in mountainous forest areas | |||||
言語 | en | |||||
著者 |
北川, 勝弘
× 北川, 勝弘× KITAGAWA, Katsuhiro |
|||||
アクセス権 | ||||||
アクセス権 | open access | |||||
アクセス権URI | http://purl.org/coar/access_right/c_abf2 | |||||
抄録 | ||||||
内容記述タイプ | Abstract | |||||
内容記述 | 本研究は、林業工学分野を対象とした山岳林地域の地形解析を、コンピュータを用いて系統的に、高精度で、迅速に、かつ簡便に行う山岳林地域の数値地形解析システムを確立することを目的としている。即ち、数値地形モデル(DTM)を用いて山岳林地域の地形特性を可能な限り原図に近い状態で再現するためには、格子状のDTMの作成方法をどのようにすれば最も高い精度が得られるのか、また、DTMの基本的な応用方法は如何にあるべきかについて基礎的な検討を行ったものである。このために、林業工学の立場から見て必要な精度をもつ格子状DTMの作成方法を開発し、DTMを用いた山地地形計測の傾斜因子に関する精度の分析を行うとともに、同じくDTMに基づく山地流域の系統的な構造解析法を開発し、さらにそれらの検討結果を踏まえて、山岳林地域の数値地形解析システムの構築を行った。第I章では、地形が複雑で急峻な山地を対象とするわが国の林業工学分野において、地形解析が重要な意義をもち、DTMをこの分野で適用するうえで、山地の傾斜因子に関する精度の把握や山地の流域構造の系統的な解析法の確立が重要であることを明らかにした。第II章では、高精度の格子状DTMを作成するためのシステム開発に関し、等高線のもつ最大傾斜線情報の活用がDTMの作成労力軽減と精度向上に有効であり、高密度記憶方式を用いた点列データ格納方式の開発により、2次元配列の記憶領域に格納された等高線点列データを任意の格子点の周辺で局所的に迅速に探索し、等高線点列を正確に復元させうることを示した。次に、この等高線点列データ格納・探索方式を用いて、格子点標高の演算方法として内挿方式、外挿方式、スプライン関数補間方式、2次曲面近似方式の4つを有機的に組み合わせた、ハイブリッド方式による格子状DTM作成システムを開発した。第III章では、各種DTM作成方式のもつ作成精度の優劣を相互に比較するため、DTMに基づいて描かれる等高線と原図等高線間のズレた区域の面積に関する誤差平均幅で定義される評価指標を提起し、これを用いて各種DTM作成方式で作成されたDTMに対する精度分析を行った。その結果、高精度の格子状DTMを作成するためには、標高を求める格子点の近傍で、必要最小限の等高線点列データから格子点を通る最大傾斜線を定め、その線上で線近似の標高比例配分内挿方式と外挿方式を主体とした格子点標高の演算を行えばよいこと、従ってこの原理に従うハイブリッド方式の格子状DTM作成方式が作成精度の点で優位性をもつことを、定量的に実証した。第IV章では、DTMを用いて山地の地形計測を点と面について行う2,3の手法の精度について定量的な分析を行い、高精度で傾斜因子を推定するための条件を解明した。まず、任意の位置(点)における傾斜因子を、複数本の等高線の点列データ(線状DTM)に基づいて直接算出する方法を提起し、この方法による方位算出値が従来の手作業等よりも精度的に優れ、より詳細な地形解析が可能となることを示した。次に、格子状DTMに基づく格子面の傾斜推定精度について検討し、傾斜近似方法としては格子の4隅の標高を用いる2次式近似で実用上十分であり、傾斜因子を正確に把握するには、標高推定を目的とする場合に比べて格子間隔を一層小さくする必要があることを明らかにした。この結果に基づき、傾斜の推定精度を考慮した縮尺別の適性格子間隔を求めた。第V章では、DTMに基づいて山地の流域構造を系統的に解析するシステムの開発に関し、先ず、水系図作成に際して疑似水流の発生を防ぐための「水源発生の4パターン」を提起し、次にホートンの水流次数の考え方に基づき小流域を自動的に区分するための諸アルゴリズムについて検討した。このシステムを用いることにより、2次水流以上の流域構造解析結果については、原図等高線図と良く合致する水系構造図を作成しうることを確かめた。第VI章では、DTMに関する以上の総合的な検討結果に基づいて、山岳林地域の数値地形解析システムを提起し、このシステムが山岳林地域の局所的もしくは広域的な地形構造についての迅速、簡便な解析を可能ならしめ、山岳林地域の地形解析を行ううえで有効であることを実証した。 | |||||
言語 | ja | |||||
抄録 | ||||||
内容記述タイプ | Abstract | |||||
内容記述 | The aim of this paper is on the whole to establish the “digital terrain analysis system for mountainous forest areas ” (DTAS) which is able to analyze the topographic characteristics of mountainous forest areas for forest operational planning and forest engineering use with a high degree of accuracy, systematically, rapidly and easily by using a large frame computer. At first this paper deals with some fundamental investigations on the condition that the topographic characteristic of mountainous forest areas would be reproduced accurately, as similar to an original map as possible through the digital terrain model (DTM) which expresses the landform by an aggregation of three-dimensional coordinate values. Secondly, it treats about how the fundamental and effective application of the DTM to forest engineering use is. Finally the DTAS is proposed as a basic tool for forest engineering use. This paper consists of four main subjects ; 1) Development of the new generation system of the grid DTM with a high accuracy adequate for forest engineering use, 2) Accuracy analyses of slope factors estimated through the DTM in mountainous areas, 3) Development of the new system analyzing the catchment basin of a mountainous area into more fundamental and smaller catchment basins, and 4) Establishment of the DTAS based upon results of the above-mentioned subjects. In Chapter I, the significance of the terrain analysis for forest engineering in Japan was discussed because many research subjects in forest engineering were connected with mountainous areas of the complicated and steep topography. It was also emphasized that to estimate the accuracy of slope factors and to develop the systematic method of analyzing the catchment basin structure were both very important on applying the DTM for forest engineering use in Japan. Chapter II threw light on some requirements for development of the generation system of the highly-accurate grid DTM. At first it was discussed that the use of digitized contour data was a good labour-saving device for generating the grid DTM, and that it was effective for improving the accuracy of the DTM generated to make use of the information of the maximum slope (a water falling line) through each grid point estimated by contour data picked up locally around the grid point. Next, the new contour data storing method in the two dimensional array on the computer buffer was developed based upon two kinds of the high-density data packing methods. The comparative examination between the new data storing method and the ordinary one revealed that the new method was superior to the ordinary one. This was because the former brought about a quicker way of searching for contour data necessary for calculation of the grid point elevation and also brought about the correct reconstruction of the contour data just as they were captured in the local area around each grid point. Based upon the above-mentioned method for contour data storing and searching, the new generation system of the highly accurate grid DTM was developed by combining the four methods for calculating a grid point elevation ; the linear interpolation, the linear extrapolation, the Spline function interpolation, and the quadratic polynomial interpolation. The new system was named “Hybrid system” after combination of the four elevation calculating methods. Chapter III compared the above-mentioned Hybrid system with other DTM production systems in the accuracy of the landform reconstructed through each DTM. The new index for estimating the accuracy of each DTM was proposed as the mean areal discrepancy width between contour lines of the original map and the ones regenerated through the DTM within the objective area. The comparative experiments revealed that the highly-accurated DTM should be generated in the following way ; Firstly, a minimum and requisite digitized contour data should be searched for calculation of the grid point elevation in the local area around the grid point. Secondly, the maximum slope line through the grid point should be determined based upon the contour data picked up. Finally, the grid point elevation should be calculated mainly through the linear interpolation and the linear extrapolation on the maximum slope line. The Hybrid system was based on the above-mentioned theory, so it was quantitatively demonstrated that the Hybrid system was superior to the others with respect to the accuracy of the DTM generation. Chapter IV analyzed quantitatively the accuracy of slope factors estimated through the DTM, and proved the conditions of the slope factor estimation with high accuracy. At first, the method of estimating slope factors at an arbitrary coordinate point was proposed. This was directly based upon digitized contour data on plural contour lines picked up in the local area around the point. It was shown that this new method was superior to the traditional manual operation with respect to the accuracy of the azimuth estimation, and would make a more detailed analysis of the terrain possible. Next, through numerical investigations on the accuracy of the slope factor estimation in grid cells, it was found out that it was practically sufficient to adapt the simple quadratic equation based upon four elevation values in corners of a grid cell as the slope approximation. It was also found out that the grid interval of the DTM needed for the accurate slope estimation must be shorter than that of the usual way of estimating elevation. Based upon the above-mentioned results, the optimum grid intervals corresponding to a map scale and an accuracy needed in slope estimation were proposed. In Chapter V, some subjects on developing a system for analyzing the structure of catchment basins of mountainous forest areas through the DTM were studied. The first subject was about how to avoid the occurrence of pseudo-streams at the systematic stream-network-map generation through the DTM. For this subject, the four occurrence patterns of a streamhead based upon the DTM were proposed after critically observing the real map with overdrawn contour lines reconstructed thorough the DTM and grid lines. Secondly, in order to systematically dividing the catchment basin into smaller ones, some algorithms were proposed based upon the HORTON’s law on the stream order. It was confirmed that the application of these algorithms to the test area’s catchment brought about a good stream-network-map generation which corresponded well to the original contour map, at least in the case of second or higher order streams. Chapter VI proposed the digital terrain analysis system for mountainous forest areas (DTAS) based upon all the above-mentioned investigations. It was confirmed that the DTAS made it possible to analyze the terrain structure of mountainous forest areas rapidly and with ease. The DTAS worked well with both smaller and larger areas, and was also found useful for the terrain analysis for mountainous forest areas. | |||||
言語 | en | |||||
内容記述 | ||||||
内容記述タイプ | Other | |||||
内容記述 | 農林水産研究情報センターで作成したPDFファイルを使用している。 | |||||
言語 | ja | |||||
出版者 | ||||||
出版者 | 名古屋大学農学部付属演習林 | |||||
言語 | ja | |||||
言語 | ||||||
言語 | jpn | |||||
資源タイプ | ||||||
資源タイプ識別子 | http://purl.org/coar/resource_type/c_6501 | |||||
資源タイプ | departmental bulletin paper | |||||
出版タイプ | ||||||
出版タイプ | VoR | |||||
出版タイプResource | http://purl.org/coar/version/c_970fb48d4fbd8a85 | |||||
ID登録 | ||||||
ID登録 | 10.18999/bulnuf.11.39 | |||||
ID登録タイプ | JaLC | |||||
関連情報 | ||||||
関連タイプ | isVersionOf | |||||
識別子タイプ | URI | |||||
関連識別子 | http://rms1.agsearch.agropedia.affrc.go.jp/contents/JASI/pdf/academy/56-1665.pdf | |||||
ISSN(print) | ||||||
収録物識別子タイプ | PISSN | |||||
収録物識別子 | 0469-4708 | |||||
書誌情報 |
ja : 名古屋大学農学部演習林報告 巻 11, p. 39-192, 発行日 1991-12 |
|||||
フォーマット | ||||||
値 | application/pdf | |||||
著者版フラグ | ||||||
値 | publisher | |||||
URI | ||||||
識別子 | http://hdl.handle.net/2237/8691 | |||||
識別子タイプ | HDL |