• Title, Summary, Keyword: Spatial range

Search Result 1,176, Processing Time 0.046 seconds

Spatial Variability of Soil Properties using Nested Variograms at Multiple Scales

  • Chung, Sun-Ok;Sudduth, Kenneth A.;Drummond, Scott T.;Kitchen, Newell R.
    • Journal of Biosystems Engineering
    • /
    • v.39 no.4
    • /
    • pp.377-388
    • /
    • 2014
  • Purpose: Determining the spatial structure of data is important in understanding within-field variability for site-specific crop management. An understanding of the spatial structures present in the data may help illuminate interrelationships that are important in subsequent explanatory analyses, especially when site variables are correlated or are a combined response to multiple causative factors. Methods: In this study, correlation, principal component analysis, and single and nested variogram models were applied to soil electrical conductivity and chemical property data of two fields in central Missouri, USA. Results: Some variables that were highly correlated, or were strongly expressed in the same principal component, exhibited similar spatial ranges when fitted with a single variogram model. However, single variogram results were dependent on the active lag distance used, with short distances (30 m) required to fit short-range variability. Longer active lag distances only revealed long-range spatial components. Nested models generally yielded a better fit than single models for sensor-based conductivity data, where multiple scales of spatial structure were apparent. Gaussian-spherical nested models fit well to the data at both short (30 m) and long (300 m) active lag distances, generally capturing both short-range and long-range spatial components. As soil conductivity relates strongly to profile texture, we hypothesize that the short-range components may relate to the scale of erosion processes, while the long-range components are indicative of the scale of landscape morphology. Conclusion: In this study, we investigated the effect of changing active lag distance on the calculation of the range parameter. Future work investigating scale effects on other variogram parameters, including nugget and sill variances, may lead to better model selection and interpretation. Once this is achieved, separation of nested spatial components by factorial kriging may help to better define the correlations existing between spatial datasets.

Adaptive Range Aggregation Index Method for Efficient Spatial Range Query in Ubiquitous Sensor Networks (USN환경에서 효율적인 공간영역질의를 위한 적응형 영역 집계 인덱스 기법)

  • Li, Yan;Eo, Sang-Hun;Cho, Sook-Kyoung;Lee, Soon-Jo;Bae, Hae-Yeong
    • Journal of Korea Spatial Information System Society
    • /
    • v.9 no.2
    • /
    • pp.93-107
    • /
    • 2007
  • In this paper, an adaptive range aggregation spatial index method is proposed for spatial range query in ubiquitous sensor networks. As the ubiquitous sensor networks are the new information-oriented paradigm, many energy efficient spatial range query methods in ubiquitous sensor networks environment are studied vigorously. In sensor networks, users can monitor environment scalar data such as temperature and humidity during user defined time and spatial ranges. In order to execute spatial range query efficiently, rectangle based index methods are proposed, such as SPIX. But they define the return path as the opposite of its query transmit path. However, the sensor nodes in queried ranges are closed to each other, they can't aggregate the sensed value in a queried range because their query transmission paths are different. As a result, the previous methods waste energy unnecessarily to aggregate sensing data out of the queried range. In this paper, an adaptive aggregation index method is proposed that can aggregate values in a user defined range adaptively by using its neighbor information. It is shown that sensor power is saved efficiently by using the proposed method over the performance evaluation.

  • PDF

Spatial Resolution and Dynamic Range Enhancement Algorithm using Multiple Exposures (복수 노출을 이용한 공간 해상도와 다이내믹 레인지 향상 알고리즘)

  • Choi, Jong-Seong;Han, Young-Seok;Kang, Moon-Gi
    • Journal of the Institute of Electronics Engineers of Korea SP
    • /
    • v.45 no.6
    • /
    • pp.117-124
    • /
    • 2008
  • The approaches to overcome the limited spatial resolution and the limited dynamic range of image sensors have been studied independently. A high resolution image is reconstructed from multiple low resolution observations and a wide dynamic range image is reconstructed from differently exposed multiple low dynamic range in es based on signal processing approach. In practical situations, it is reasonable to address them in a unified context because the recorded image suffers from limitations of both spatial resolution and dynamic range. In this paper, the image acquisition process including limited spatial resolution and limited dynamic range is modelled. With the image acquisition model, the response function of the imaging system is estimated and the single image of which spatial resolution and dynamic range are simultaneously enhanced is obtained. Experimental results indicate that the proposed algorithm outperforms the conventional approaches that perform the high resolution and wide dynamic range reconstruction sequentially with respect to both objective and subjective criteria.

A Multi-dimensional Range Query Processing using Space Filling Curves (공간 순서화 곡선을 이용한 다차원 영역 질의 처리)

  • Back, Hyun;Won, Jung-Im;Yoon, Jee-Hee
    • Journal of Korea Spatial Information System Society
    • /
    • v.8 no.2
    • /
    • pp.13-38
    • /
    • 2006
  • Range query is one of the most important operations for spatial objects, it retrieves all spatial objects that overlap a given query region in multi-dimensional space. The DOT(DOuble Transformation) is known as an efficient indexing methods, it transforms the MBR of a spatial object into a single numeric value using a space filling curve, and stores the value in a $B^+$-tree. The DOT index is possible to be employed as a primary index for spatial objects. However, the range query processing based on the DOT index requires much overhead for spatial transformations to get the query region in the final space. Also, the detailed range query processing method for 2-dimensional spatial objects has not been studied yet in this paper, we propose an efficient multi-dimensional range query processing technique based on the DOT index. The proposed technique exploits the regularities in the moving patterns of space filling curves to divide a query region into a set of maximal sub-legions within which space filling curves traverse without interruption. Such division reduces the number of spatial transformations required to perform the range query and thus improves the performance of range query processing. A visual simulator is developed to show the evaluation method and the performance of our technique.

  • PDF

SPATIAL NUMERICAL RANGES OF ELEMENTS OF $C^*$-ALGEBRAS

  • Takahasi, Sin-Ei
    • Bulletin of the Korean Mathematical Society
    • /
    • v.37 no.3
    • /
    • pp.537-542
    • /
    • 2000
  • When A is a subalgebra of a $C^*$-algebra, the spatial numerical range of element of A can be described in terms of positive linear functionals on the $C^*$-algebra.

  • PDF

Range and k-Nearest Neighbor Query Processing Algorithms using Materialization Techniques in Spatial Network Databases (공간 네트워크 데이터베이스에서 실체화 기법을 이용한 범위 및 k-최근접 질의처리 알고리즘)

  • Kim, Yong-Ki;Chowdhury, Nihad Karim;Lee, Hyun-Jo;Chang, Jae-Woo
    • Journal of Korea Spatial Information System Society
    • /
    • v.9 no.2
    • /
    • pp.67-79
    • /
    • 2007
  • Recently, to support LBS(location-based services) and telematics applications efficiently, there have been many researches which consider the spatial network instead of Euclidean space. However, existing range query and k-nearest neighbor query algorithms show a linear decrease in performance as the value of radius and k is increased. In this paper, to increase the performance of query processing algorithm, we propose materialization-based range and k-nearest neighbor algorithms. In addition, we make the performance comparison to show the proposed algorithm achieves better retrieval performance than the existing algorithm.

  • PDF

The Qualifications for the Application of the Rainfall Spatial Distribution Analysis Technique (강우량 공간분포 분석기법의 적용조건에 관한 연구)

  • Hwang Sye-Woon;Park Seung-Woo;Cho Young-Kyoung
    • Proceedings of the Korea Water Resources Association Conference
    • /
    • /
    • pp.943-947
    • /
    • 2005
  • This study was intended to interpose an objection about the analysis of rainfall spatial distribution without a proper standard, and offer the improved approach using 1,he geostatistical analysis method to analyze it. For this, spatially distributed daily rainfall data sets were collected for 41 weather stations in study area, and variogram and correlation analysis were conducted. In the results of correlation analysis, it was found that the longer distance between the stations reduces the correlation of the rainfall data, and maltes the characteristics of the rainfall spatial distribution. The variogram analysis shows that correlation range was less than 50 km for the 17 daily rainfall data sets of total 91 sets. It says that it involves some rike, to determine the application method for rainfall spatial distribution without some qualifications, hence the Application standards of the Rainfall Spatial Distribution Analysis Technique, were essential and that was contingent on characteristics of rainfall and landscape.

  • PDF

Automated texture mapping for 3D modeling of objects with complex shapes --- a case study of archaeological ruins

  • Fujiwara, Hidetomo;Nakagawa, Masafumi;Shibasaki, Ryosuke
    • Proceedings of the KSRS Conference
    • /
    • /
    • pp.1177-1179
    • /
    • 2003
  • Recently, the ground-based laser profiler is used for acquisition of 3D spatial information of a rchaeological objects. However, it is very difficult to measure complicated objects, because of a relatively low-resolution. On the other hand, texture mapping can be a solution to complement the low resolution, and to generate 3D model with higher fidelity. But, a huge cost is required for the construction of textured 3D model, because huge labor is demanded, and the work depends on editor's experiences and skills . Moreover, the accuracy of data would be lost during the editing works. In this research, using the laser profiler and a non-calibrated digital camera, a method is proposed for the automatic generation of 3D model by integrating these data. At first, region segmentation is applied to laser range data to extract geometric features of an object in the laser range data. Various information such as normal vectors of planes, distances from a sensor and a sun-direction are used in this processing. Next, an image segmentation is also applied to the digital camera images, which include the same object. Then, geometrical relations are determined by corresponding the features extracted in the laser range data and digital camera’ images. By projecting digital camera image onto the surface data reconstructed from laser range image, the 3D texture model was generated automatically.

  • PDF

The Land Surface Temperature Analysis of Seoul city using Satellite Image (위성영상을 통한 서울시 지표온도 분석)

  • Jeong, Jong-Chul
    • Journal of Environmental Impact Assessment
    • /
    • v.22 no.1
    • /
    • pp.19-26
    • /
    • 2013
  • The propose of this study is to analyze the optimum spatial resolution of the urban spatial thermal environment structure and to evaluate of the possibility detection using aerial photographs and thermal satellite images. The proper techniques of the optimum spatial resolution for the urban spatial thermal environment structure were analyzed. Thermal infrared satellite image of Seoul city were used for the change rate of surface temperature variation and suggested to the spatial extent and effects of urban surface characteristics and spatial data was interpreted as regions. To extract the surface temperature, Landsat thermal infrared satellite image compared with an automatic weather station data and in the field of the measured temperature and surface temperature by thermal environment affects, the spatial domain has been verified. The surface temperature of the satellite images to extract after adjusting surface temperature isotherms were constructed. The changes in surface temperature from 2008 to 2012 the average surface temperature observation images of changing areas were divided into space. The results of this study are as follows: Through analysis of satellite imagery, Seoul city surface temperature change due to extraction comfort indices were classified into four grades. The comfort index indicative of the temperature of Gangnam-gu, $23.7{\sim}27.2(^{\circ}C)$ range and Songpagu, a $22.7{\sim}30.6(^{\circ}C)$ respectively, the surface temperature of Yeouido $25.8{\sim}32.6(^{\circ}C)$ were in the range.