| Spatial-Temporal data model is a description of the process of change in the geographic phenomenon data model, plays a vital role in the process of spatial and temporal watershed simulation, and it described expression changes that are stored in the computer. The description of the geographic variation of temporal data model entities have a lot of extensions, such as static data model, object-oriented temporal data model, temporal data model based on object change, temporal integration of temporal data model to process the core of temporal data model, based on geometric multidimensional unified data model algebra. Currently, the space-time watershed data model is existed such as data model for a particular hydrological model of the system, and integrated hydrological model. But the temporal data model time series of these watershed hydrology expressed as properties of spatial objects, spatial variation of operation to achieve by changing the state of an object at different times to contact stealth way of expressing time and space, this approach can only express its spatial relations changes, but cannot express the object changes reasons, the trends and other issues over time. But most of Basin water resources model and its application are often predicted to reflect changing trends, dynamics reflect retroactive changes. A temporal data model based on the process described in this study, according to the characteristics of the phenomenon of the change process introduced watershed time dimension, time cube concept, change the axis from the time domain to describe the spatial and temporal changes in the spatial domain watershed process, thematic attribute domain. That is, the geographic entities abstracted into a cube unit, the change process of basin geographical entities abstracted into a dimension axis (e.g. time dimension axis) on the entity axis in the other dimensions within a certain period of time such as changes in water level changes in a river situation. Time information for geographic entity described in the time dimension cube axis corresponding time attributes. Predicting changes in watershed conditions and trends entity over time, just only retrieve simply the corresponding entity axis time point in the time dimension is mapped to spatial dimension, or dimension attribute information on the topic. This kind of temporal data model to solve the current watershed basin temporal data model using a time series as the spatial properties of an object, the relationship between spatial variation by changing the operating state of the object at different times to get in contact the implicit way of expressing time and space to describe the spatial relationships and problems such as the change. About the specific research work is represented as follows:(1)Firstly, research status about spatial-temporal expression watershed phenomenon temporal data model analyzed. The advantages and disadvantages of these models analyzed, the characteristics and applications of different spatiotemporal data explained, and the development trend about temporal data model discussed. Secondly, the change in the geographic phenomenon watershed analysis process spatial characteristics of geographic entities, the time characteristics, the characteristics of the underlying property, the time of geographical entities, space, property broken down into time, unified whole spatial and attribute domain association. Meanwhile, the description for the time and special properties of the current focus on the problem summed up time features, attributes and spatial characteristics of change characteristic change of12scene changes.(2) From up to resolve geographical entity in life-cycle changes, geographic spatial and temporal to produce the decomposition the three stages of the process. In the analysis of the spatial characteristics of geographic phenomena watershed change the course of geographical entities, temporal characteristics, characteristics of the property on the basis of the topic, the decomposition time geographic entities, spatial and attribute information into time, space related, Meanwhile, the expression for the current focus on the issue thematic property division unified of time and special attributes, the watershed time characteristics and special features associated with changes summarized in the properties of the12scene changes, and it is good to elaborate subsequent expression model using previous research concerns. Based on characteristics of the introduction and expression of the time dimension of the problem in the time domain, in this study, the process of expressing time dimension atomic basin phase change unit entity elaborated. Presented snapshots and introducing a time dimension model is based on the time stamp method, based on snapshots and analytical method based on the time stamp at the physical layer of tissue, layer process algebraic expression, the space between the vertical space geometric surface layer mapping based analytic snapshot timestamp method based relationship between the time dimension, spatial dimension, a dimension transverse dimension attributes. Combined with spatial and temporal characteristics of the phenomenon and the spatial and temporal changes in watershed basin of space-time phenomenon presents a thematic structure basin architecture to achieve process diagram and detailed description of the process of expressing geographic entity object method is proposed process described in a four-tuple expression, based on the model of spatial and temporal expression of the storage structure and the temporal relationship between watershed processes relationships.(3) On the basis of analysis of the phenomenon and the hydrographic basin temporal characteristics of the geographical entity, describing an approach based on river basin, sub-basin, watershed characteristics atomic unit logic, the logic relationship between the expression of hydrological factors such as river basins, river, lake etc. And relationship basin water project elements reservoirs, canals, dams, etc. Describe the spatial-temporal watershed process of time, space, special attributes and relationships from the perspective of atomic unit object, given the realization of the relationship between them. Taking into account the object-oriented technology in the abstract and schematic geographic entity attributes and ease of operation, the use of object-oriented technology and expression basin indicate the geographical entity abstract entities into objects. Analysis of the expression of physical objects basin geometry features, the geographical entity described basin abstract spatial objects into parts, part of the time-domain objects, attributes, and object parts. Given point change in the geographical entity part of the basin object space objects, methods, line, surface, volume data description and organization; timestamp changes when describing the geographic entity object watershed domain objects part time tissue expression methods; analysis of the watershed changes in the geographical entity thematic attribute domain object properties of the object part of the topic, the type of tissue expression methods.(4) Watershed basin hydrological processes in response to rainfall events, is a complex natural phenomena under the combined effect of the local geography and climate and land surface conditions. First, a general description of the process based on changes in the program to express geographical phenomena watershed process, proposed changes in the geographic phenomenon of a watershed simulation framework, which nested generic process model simulation framework watershed basin can easily simulate changes in the geographic phenomenon processes. The kind of retrospective simulation framework to dynamically change the course of development, but also to describe the physical changes in the geographical dimension of the case based on a watershed. The same process applies to a different kind of framework watershed event geographic variation simulation. For example basin rainfall flooded process simulation, process simulation watershed dam flooded, the only difference lies in the different abstraction module out of the basin calculus, calculus model of the module to be based on a different process variations using different watershed model, concluded the process of atomic unit the data required for the desired spatial, temporal, domains. Secondly, the process of rainfall-runoff flooding as an example shows the watershed model to simulate the process of a common framework that integrates the model programs in this framework:the watershed area of uniform size progressively divided into hydrological response units. Combined watershed soils, land use, topography and other factors affect runoff using rainfall level information related to rainfall, simulated rainfall runoff hydrological response of each process unit, the convergence process, flooding process, the establishment of watershed rainfall, runoff, flooding process calculation models. Specific Integrated implementation:①Based on the characteristics of the study area rivers, DEM terrain data and rainfall level data, the analysis of the soil moisture level watershed unit, soil type, land use types, based on the use of SCS runoff model to analyze the calculated basin unit flow;②in Muskingum method using the water balance equation and channel storage curve equation combined calculus export unit sinks river flow;③Due to the large river basin upstream slope of the study area, using a formula to calculate Manning river study area the water level.④DEM terrain combined with water and watershed basin flooded, submerged horizontal and geographic units using DEM tangential approach to calculus flooded area range.(5) It is Analysis that the geographic location of the study area, water distribution, basic overview of hydrological and meteorological characteristics, vegetation and soil. Introduced the research area involves the simulation of terrain data base, thematic data, business data. Based on the basic data of the study area watershed basin filled depressions, river basin flow, flow accumulation, watersheds river network, drainage sub-basin is divided treatment for the runoff process offers flooded river basin network infrastructure. Basin water level due to the acquisition of data is easier to get through the measuring station, taking into account the characteristics of the study area and for the river basin network flow, using active submerged model to simulate the water level in the study area based on the scope and depth of inundation flooded area, study area measured data and geographic terrain data base to achieve a combination of simulated situations Changhua River basin upstream region flooded area daily distribution. From the point of view changes in inundated areas, flooded the lower range of the initial period, followed by periods with the sharp rise in the water level in the flooded basin expand the scope of the third period to narrow the water flooded down to the fourth moment submerged area watershed rainfall weakened sharply. Examples of simulation results show that the process of changing trends and trace element temporal watershed geographic entity data model based on process can better express basin. |
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