Wyniki wyszukiwania - BazTech

1

Zastosowanie metody Chrobaka upraszczania linii w rastrowych technikach pozyskiwania danych

Żukowska M., Kozioł K.

Roczniki Geomatyki

|

2007

|

T. 5, z. 2

85-93

EN

The evolution of remote sensing techniques observed in last years has a meaningful influence on data acquisition. High resolution of aerial and satellite remote sensing data causes necessity of using appropriate generalization techniques of elaborated objects. Through high spatial resolution modern imaging technology allows to acquire highly detailed objects. Moreover, acquired objects have geometric characteristics closely connected with raster model structure (a grid), what often does not correspond with actual characterstics of registered objects. In the paper, the authors attempt to elaborate rules for using cartographic line and polygon generalization algorithms to simplify objects formed in image classification. A classified image is vectorized with separated classes maintained. As a result we obtain a set of broken lines forming polygon borders. To achieve appropriate graph of determined lines they need to be simplified. To simplify broken lines Chrobak.s objective line simplification algorithm was selected. At this stage, the number of vertices forming particular borders is considerably reduced. Afterwards those lines are processed so as to remove vertices with sinuosity value less than 1.1. It is assumed that such broken line segments can be recognized as .nearly straight.. The last stage is connected with removing some inconsistency or graphic conflicts, which could occur during primitive line simplification or partially in automatic image classification. Border vertices buffering and displacement is used here. Buffer and displacement size is strictly connected with modified drawing legibility.

2

Generalizacja warstwy zabudowy z zastosowaniem regionów drogowych na przykladzie bazy danych topograficznych

Szostak M.

Roczniki Geomatyki

|

2006

|

T. 4, z. 3

219-228

EN

In this paper characteristics of the generalization process of the topographic database in the layer of built-up area was presented. The elements of this layer make the content of topographic and thematic maps and they are also subdued to significant changes during a change of scale. The proposed way of generalization of built-up area is based on the establishing of recognition of the content on the topographic map, in any selected timescale. The base for the correct generalization of objects of selected builtup area and a definite scale of a topographic map is the definition of the ability to recognize individual objects. This process leads to making complex objects that are made by a proper aggregation of individual objects possessing common edge outlining single buildings. The main subjects of the paper include simplification of the shape and the elimination of sectors in the built-up area and buildings, as well as the definition of conditions of automatic change in the method of presentation of built-up area (buildingsŽ built-up areas). In the discussed processes, the usefulness of the application of structural regions in the classification and elimination of internal objects was shown.

3

Eliminacja obiektów liniowych z zastosowaniem regionów strukturalnych na przykładzie sieci drogowej

Kozioł K.

Roczniki Geomatyki

|

2006

|

T. 4, z. 3

109-117

EN

Elimination of objects in any database must be based on their earlier sorting. This is one of numerous problems we come across during the process of digital generalization of objects. Obtaining a clear classification of objects usually leads to too extensive development of the domain of descriptive attributes. The author tries to prove that it is useful to make structural regions for the network of linear objects such as roads, rivers or railways for the classification of objects, using the smallest number of attributes. The created classification allows automatic elimination of the network objects. To illustrate the mentioned above issues a fragment of a topographic database was selected. It was the layer of the road network. In the paper, the problem of necessary conditions to form regions is also presented as well as the way of classification of created regions. After making the classification of structural regions of the road network, the process of automatic elimination of regions is presented. It is made by the aggregation with one of the neighboring regions. Elimination through aggregation is based on fully automatic processes and verifiable values of attributes. The carried out process is independent from the situation of objects and the applied software, although it requires application of the accepted model of data.