| This system which adopts the development method of geographic information system based on component applies TopMap ActiveX plug-in under the development platform of Visual Basic programming language. Through managing layers and database, the software could demonstrate source apportionment of atmospheric particulates information system in map visualization, dynamic query and data statistics/comparison in the form of thematic layers, and put forward to reference for policymakers who want to work out measures which can reduce the pollution caused by atmospheric particulates in some north province.Source Apportionment of Atmospheric Particulates Information System is formed mainly by two major parts: (1) Map Operation Module, which include calling in layers, loading exterior data (source and acceptor data), adding and deleting one layer of attribute information, creating and deleting thematic layers and isoline layers, saving and printing maps, and so on. (2) Database Management Module, which include data query and maintenance, and so on. Source Apportionment Project Database takes the ground floor link way between modules, and realizes the data share.Geographic Information System which is prompt, accurate and including amount of map information and various organized data information can meet user's demands. It is important way that Geographic Information System deals with space data and attribute-data of layers, which makes database management easy. The base maps which we select in the system are the digital map (1:50000) of some north province. Through dealing with them, we have formed the base maps which are called in and assessed. We can add or delete layers at any time by TopMap ActiveX plug-in, and deal with every layer. We can also create new temporary layers (such as isoline layer), show the temporary data, and acquire new data according to special conditions. Once these temporary layers are not needed again, we can delete them at any time. As to modifying the attribute of layers ,we mainly adopt two kinds of method: (1) Calling in layer manager of TopMap ActiveX plug-in by LayerCtrlDlg function which can move arranged position of layers, set the visibility, selectivity and edited flexibility of layers, and load any existing layers; (2) Through writing function code of LayerCreate, LayerAdd and LayerDelete, we can create, add and delete layers, change relative position of point, line and surface layers, and set the attributes (such as form, size and color) of added symbols.Utilizing this characteristic of TopMap ActiveX plug-in, we can conveniently create pollutant distribution layers, thematic layers and isoline layers, stack layers reasonably, and show different information of layers at one map.There are column chart, pie chart and stack chart in TopMap ActiveX plug-in in order to show data by graph. Users can choose the formulation way of thematic layers at will in the operating process. Through writing the program code of different thematic layers, the system will create the related layer automatically. Picturizing the result must have the related data, so the software system must integrate and show space-data and attribute-data, and link the related attribute-data database with TopMap ActiveX plug-in. The development of the system mainly adopts ADO interface of the database, which link with the attribute database. Under thematic map window, layer-attribute list box can show all field-information of every entity at any time. When we exit the software, the system will save the thematic map automatically. Moreover, when we enter the software next time, the system will remove the thematic map and all field-information of pollution factors in layer-attribute list box. When the software is running, if user want to reserve some thematic maps, he can realize it through the following two methods: (1) Use "Output Picture" button and save layer-information as "*.jpg", "*.bmp" and "*.gif" etc., which includes 14 picture formats; (2) Use "Print" button and save layer-information as paper files after preview.The isoline layer can clearly show the distribution regularity of one factor in certain area, which has good reference value of making treatment measures which reduce district pollution of atmospheric particulate matter. In TopMap ActiveX plug-in, isoline layer is created on the basis of surface entity; interpolation algorithm apply polyhedral function algorithm, and set interstage numbers according to pollution factors. After creating isoline layer, layer-attribute list box will show automatically classified array sets, and set new isoline layer as current layer. When we exit the software, the system will automatically name new layer as "Isoline Layer", and save it in the folder which storage all layers. In order to make sure that the software can create new layer next time, the system will automatically delete "Isoline Layer" when enter the software again. If user wants to reserve new layer, except two ways given above, we can also cut "Isoline Layer" and reserve it in another folder in order to be called in for the future.The system integrate monitoring data (city A, city B, city C and city D) of source apportionment and relevant statistical data of each city about development of society and economy, and save them on the basis of data table in Access database. Data query is the main means that the system offers data to user. The software has storaged a large number of monitoring data and statistical data about development of society and economy in the system, and maintain two databases at any time. Consulting the result of source apportionment, which can enhance the pertinence, scientificity and rationality of prevention and control of atmospheric particulates pollution, we can establish the plan of prevention and control of air pollution. In recent years, source apportionment technology plays an important role in the research on the total quantity of atmospheric particulates control and comprehensive treatment of urban environment, and we have acquired good social benefit and environmental benefit. After introducing GIS technology as study means, the lacks of connection about environmental information data and intuitionistic expression are remedied. In this GIS system, we can show the information of distribution disciplinarian, pollutant sources and pollution extent about each city in some north province, compare the changes of atmospheric environment quality about each city according to pollutant sources'contribution and contribution rate to atmospheric particulates in the different areas and periods, and put forward the suggestion measures about prevention and control of atmospheric particulates.Meanwhile, the software has a certain expansion. Take creating isoline layer for example, if we can ascertain the limit values of pollution factors and set different colors in every region, the information exceeded the limits about pollution factors will be very clear on the basis of urban street layer. In addition,the software has good portability. If database is altered properly,we also apply the software to other research fields. |
PDF Full Text Request