There are preliminary results [11] on the use of discrete basis and bounding errors with peg-board semantics. Another related problem con- cerns interpolation to estimate the continuous field from a discretization.
Negative spatial autocorrelation makes in- terpolation error-prone. Further work is needed on a framework to formalize the discretization process, its asso- ciated errors, and on interpolation. In addition, there has been very little work toward developing data models, data types e. Similarly, there is a need for developing the field data model [33] toward a field-based query language. Opera- tions on fields will be needed to help derive new informa- tion such as land-cover classification; the fields involved include temperature, texture, and water content, and are obtained through imaging in different bands such as infra- red, visible bands, or microwave.
Cost models are used to rank and select the promising processing strategies, given a Fig. In as the semantic gap between relational operators and spa- the spatial situation the relative cost per tuple of Area and tial operation. Cost models are needed to estimate the se- Distance is an important factor in deciding the order of lectivity of spatial search and join operations toward com- the operations [13].
Depending upon the implementation of parison of execution-costs of alternative processing strate- these two functions the optimal strategy may be to process gies for spatial operations during query optimization. Pre- the join before the select operation see Fig. However, there is a need to develop and evaluate Similarly, common strategies employed in traditional strategies for many other frequent queries such as those in databases for the logical transformation step in query optimi- Table 4.
These include queries on objects using predicates zation may not be always applicable in the context of spa- other than overlap and queries on fields such as slope tial databases. For example consider the query see Fig. Bulk loading strategies for puted and that its value is computed afresh every time it spatial data also need further study. A query tree generated for the query is shown in Fig. Further work is needed, both to char- to explore the impact of querying by pointing and visual acterize the access patterns of the graph algorithms that presentation of results on database performance.
New approaches for concurrency-control techniques are needed for other In this survey, we have presented the major research ac- spatial indices. These include object-based data mod- database application.
Sequoia [30] provides an ap- eling, spatial data types, filter and refine techniques for proach toward tertiary storage files and indices. Other ap- query processing and spatial indexing.
We have also identi- proaches for managing databases on tertiary storage need fied areas where more research is needed. Some of these to be investigated. Other research needs include benchmarking, workflow Many of the spatial techniques highlighted in this sur- modeling, and the visual presentation of results. We believe that other ries in Earth Science applications. The performance of emerging multidimensional applications such as multime- loading data, raster queries, spatial selection, spatial joins, dia information systems will use these methods to solve and recursion is addressed in 11 benchmark queries.
A few problems such as searching and indexing spatial content. Similar We illustrate the possibilities in the context of multimedia benchmarks are needed to characterize the spatial data information systems with text, audio and video data over management needs of other applications such as GIS, the World Wide Web. Multimedia data has a spatial content which can be que- DWH, and transportation. For example, based on manipulating layers to produce new, derived lay- the spatial operator inside of can be applied to text to locate ers.
These channels are analogous to layers in GIS change propagation if the source layers are modified. A spatial join could de- Spatial databases may require a different type of termine all of the locations where the input from both piano concurrency support than is needed by traditional data- and voice is over a certain decibel threshold.
For example, transactions in traditional systems tend A video database such as a movie server can take ad- to be short on the order of seconds. However, in spatial vantage of techniques developed for spatial databases.
Similarly, recovery and content with objects interacting in directional relationships. There is a need to charac- based on those relationships. For example, if you cannot terize the work flow of spatial applications.
They also allow users to query the visual tionship to determine when in the movie that event took representation by pointing to the visual representation us- place. Such queries exploit the directional relationships in- ing devices like a mouse or a pen.
Further work is needed herent between all tangible objects. Liu and S. Data Eng. Laboratory Cooperative Agreement No. Patel and D. Management of Data, pp. We Addison-Wesley, Shekhar and S. Shekhar, M. Coyle, D. Liu, B. Goyal, and S. ACM, vol. Shekhar, A. Fetterer, and B. Adam and A. Asano, D. Ranjan, T. Roos, E. Wiezl, and P. Shekhar and D.
July Ravada, V. Kumar, D. Chubb, and G. Shekhar and X. Belussi and C. Very Large Data Bases, pp. Stonebraker, J. Frew, and J. Brinkhoff, H. Kriegel, and B. Management of Washington D. Data, pp. Stonebraker and G. Stonebreaker and D. Great Wave, Morgan Kaufmann, Documents Similar To Chapter Yakub Pasha. Anil Kumar Singh. Nityesh Srivastava. Elena Pislariu. Sharma Nishant. Shahbaz Khan. Dennis Millares Yape.
Pete Joempraditwong. Arindam Basu. Some One. Bicycle Thief. Vinoth Adi. Safal Raj. Prince Pierre. People and mammals in Mexico conservation conflicts at a national scale.
Moersyid Mungka. Maria Lorena Dugarte Sanchez. M A Qader. More From Bicycle Thief. Popular in Data Management. Alexandru Moldovan. Yogesh Sabale. Improve Article. Save Article. Like Article. Recommended Articles. Article Contributed By :.
Easy Normal Medium Hard Expert. Writing code in comment? Please use ide. Load Comments. What's New. Most popular in DBMS. More related articles in DBMS. We use cookies to ensure you have the best browsing experience on our website. Start Your Coding Journey Now!
0コメント