Base Point Split Algorithm for Generating Polygon Skeleton Lines on the Example of Lakes

This article presents the Base Point Split (BPSplit) algorithm to generate a complex polygon skeleton based on sets of vector data describing lakes and rivers. A key feature of the BPSplit algorithm is that it is dependent on base points representing the source or mouth of a river or a stream. The input values of base points determine the shape of the resulting skeleton of complex polygons. Various skeletons can be generated with the use of different base points. Base points are applied to divide complex polygon boundaries into segments. Segmentation supports the selection of triangulated irregular network (TIN) edges inside complex polygons. The midpoints of the selected TIN edges constitute a basis for generating a skeleton. The algorithm handles complex polygons with numerous holes, and it accounts for all holes. This article proposes a method for modifying a complex skeleton with numerous holes. In the discussed approach, skeleton edges that do not meet the preset criteria (e.g., that the skeleton is to be located between holes in the center of the polygon) are automatically removed. An algorithm for smoothing zigzag lines was proposed.

ПРОЕКТ ИНФОРМАЦИОННОЙ СИСТЕМЫ АКУСТИКО-ГИДРОФИЗИЧЕСКОГО ПОЛИГОНА МЭС «МЫС ШУЛЬЦА»

Морская экспериментальная станция (МЭС) Мыс Шульца расположена в шельфовой зоне Японского моря, в бухте Витязь Хасанского района Приморского края. Уже 40 лет здесь выполняется основная часть прибрежных экспериментальных исследований в области гидрофизики, геофизики, гидробиологии, проводятся натурные испытания приборов и оборудования, разработанного в ТОИ ДВО РАН, других организациях. МЭС Мыс Шульца является уникальным по географическому принципу местом для проведения сложнейших полигонных экспериментов. К сожалению, данные по проведенным экспериментам являются разрозненными, сведения о развитии структуры базы частично утеряны, либо хранятся на бумажных носителях в архиве института. Для решения такой проблемы является актуальным создание информационной системы МЭС Мыс Шульца . Структурно информационная система МЭС Мыс Шульца состоит из двух частей: историографической и экспериментальной. Первая часть, содержащая архивные материалы по истории создания полигона, публикации, связанные с экспериментальными исследованиями данного района, позволяет отследить этапы создания и развития МЭС Мыс Шульца . Основой второй части ИС должна стать база данных результатов экспедиций, проведенных в период 19792017г.г. на МЭС Мыс Шульца , что позволит накапливать, систематизировать, хранить и анализировать информацию о пространственновременной изменчивости акустическогидрофизических процессов в акватории, прилежащей к МЭС Мыс Шульца .The Maritime Experimental Station (MES) Cape Schulz is located in the shelf zone of the Sea of Japan, in the boot Vityaz of the Khasansky district of the Primorsky Territory. For 40 years, the bulk of coastal experimental research in the field of hydrophysics, geophysics, hydrobiology, field tests of instruments and equipment developed at the POI FEB RAS and other organizations have been carried out here. MES Cape Schulz is a unique geographical location for complex polygon experiments. Unfortunately, the data on the experiments are fragmented, the information about the development of the base structure is partially lost, or stored on paper in the institutes archive. Creation of the information system of the MES Schultz Cape is relevant for solving such a problem. The structure of the information system consists of two parts: historical and experimental. The first part contains archival materials on the history of the MES, publications related to experimental studies of the area. This information allows you to track the stages of the creation and development of the MES Cape Schulz. The database of the results of expeditions conducted in the period 19792017 at the MES Cape Schulz should become the basis of the second part of the IS. This will allow us to accumulate, systematize, store and analyze information on the spatiotemporal variability of acoustichydrophysical processes in the water area adjacent to MES Cape Schulz.

Analysis of Water Bodies under Partial Cloud Conditions Using Satellite Images

The technique of obtaining information or data about any feature or object from afar, called in technical parlance as remote sensing, has proven extremely useful in diverse fields. In the ecological sphere, especially, remote sensing has enabled collection of data or information about large swaths of areas or landscapes. Even then, in remote sensing the task of identifying and monitoring of different water reservoirs has proved a tough one. This is mainly because getting correct appraisals about the spread and boundaries of the area under study and the contours of any water surfaces lodged therein becomes a factor of utmost importance. Identification of water reservoirs is rendered even tougher because of presence of cloud in satellite images, which becomes the largest source of error in identification of water surfaces. To overcome this glitch, the method of the shape matching approach for analysis of cloudy images in reference to cloud-free images of water surfaces with the help of vector data processing, is recommended. It includes the database of water bodies in vector format, which is a complex polygon structure. This analysis highlights three steps: First, the creation of vector database for the analysis; second, simplification of multi-scale vector polygon features; and third, the matching of reference and target water bodies database within defined distance tolerance. This feature matching approach provides matching of one to many and many to many features. It also gives the corrected images that are free of clouds.

A QUADTREE SPATIAL INDEX METHOD WITH INCLUSION RELATIONS FOR THE INCREMENTAL UPDATING OF VECTOR LANDCOVER DATABASE

<p><strong>Abstract.</strong> In vector landcover database, there are a lot of complex polygons with many holes, even nesting holes. In the incremental updating (i.e., using the change-only information to update the land cover database), a new changed parcel usually has 2-dimensional intersections (e.g., overlap, cover, equal and inside, etc.) with several existing regions, automatic updating operations need to identify the affected objects for the new changes at first. If the existing parcels include complex polygons (i.e., the polygon with holes), it is still needed to determine if there are 2-dimensional intersections between the new changed polygon and each holes of the involved complex polygons. The relation between the complex polygon and its holes has not been presented in the current spatial data indexing methods, only the MBB (Minimum Bounding Box) of the exterior ring of the complex polygon has been stored, the non-involved holes can not be filtered at the first step of spatial access methods. As the refinement geometric operation is costly, therefore the updating process for the complex polygons is very complicated and low efficient using the current spatial data indexing methods. In order to solve this problem, an improved quadtree spatial index method is presented in this paper. In this method, the polygons is divided to two categories according to the relations with the quadrant axes, i.e., disjoint to the axes and intersect with the axes. The intersect polygons are still divided to 5 cases according to the intersection position among the polygons and the different level quadrant axes. The intersection polygons are stored in the different level root nodes in our index tree, and five buckets denoted as <i>XpB, XnB, YpB, YnB, XYB</i> are used to store the polygons intersecting the different level quadrant axes respectively. The polygons disjoint to all quadrant axes are stored in the leaf nodes in this method. The authors developed the spatial index structure with inclusion relations and the algorithms of the corresponding index operations (e.g., insert, delete and query) for the complex polygons. The effectiveness of the improved index is verified by an experiment of land cover data incremental updating. Experimental results show that the proposed index method is significantly more efficient than the traditional quadtree index in terms of spatial query efficiency, and the time efficiency of the incremental updating is increased about 3 times using the proposed index method than that using the traditional quadtree index.</p>

Max the Real Estate Agent

Students take on the role of a real estate agent, decomposing a complex polygon into familiar shapes to calculate a house's square footage based on the exterior-walls floor plan.

New Method for Polygonous Node Automatic Creation Based on Triangulation

According to the concept and function of polygonous node, the authors depicted that the key of methods of making polygonous node is that a node corresponding to a polygon is one by one. On the basis of analyzing the available algorithms, the method of automatic creation polygonous node based on triangle is proposed. Compared with the traditional algorithms, This method is easy and workable, high efficiency and confirmative, ensuring the creation of one by one relation between polygonous node and polygon without considering various special cases. For polygon interior of the complex polygon is off-center, the modified algorithm has some improvement, especially for convex polygons, the effect is obvious. In the process of planar vector graphics to raster graphics conversion, the author have used the above algorithm, completed each polygon area filling, and achieved the desired effect.

A Research of Matching Algorithm and Strategy on Entity with Complex Area

Data matching technology is a key technology for spatial data integration and fusion. This paper represents a solution to the complex polygon area, defines the area overlapped rate in the aspect of geometric measure, presents the data matching idea based on area overlapped rate .Then, this paper discusses and realizes the data matching relation of area elements including one to one , many to one and many to many. At last, region targets are set as the study object, large scale data are taken for example. We draw the conclusion: this algorithm is efficient.

Generalisation of Scale and Move Transformation-Based Fuzzy Interpolation

Fuzzy interpolative reasoning has been extensively studied due to its ability to enhance the robustness of fuzzy systems and reduce system complexity. In particular, the scale and move transformation-based approach is able to handle interpolation with multiple antecedent rules involving triangular, complex polygon, Gaussian and bell-shaped fuzzy membership functions [1]. Also, this approach has been extended to deal with interpolation and extrapolation with multiple multi-antecedent rules [2]. However, the generalised extrapolation approach based on multiple rules may not degenerate back to the basic crisp extrapolation based on two rules. Besides, the approximate function of the extended approach may not be continuous. This paper therefore proposes a new approach to generalising the basic fuzzy interpolation technique of [1] in an effort to eliminate these limitations. Examples are given throughout the paper for illustration and comparative purposes. The result shows that the proposed approach avoids the identified problems, providing more reasonable interpolation and extrapolation.