Mapsheet Index

Principle

In SuperMap SDX +, the spatial objects are classified according to a Property Field of Dataset or a given range (the length and width of the map), and the classified spatial objects are managed through the index, so as to improve the query and retrieval speed. As shown in the figure below, it is a composite map of the municipal administrative boundary map of China. After the Maps heet Index is created according to the given range, the scene of h4708 is displayed. Mapsheet Index is particularly advantageous when displaying and querying massive data (that is, data with more than one million objects). After the Mapsheet Index is created, only the map or maps you need to view are displayed, which greatly shortens the Display Time.

　
Figure: Maps heet Index diagram

In particular, the Mapsheet Index can also be cached locally (in the form of a binary file), which can further improve the speed of query retrieval. File caching is an intelligent distributed storage solution provided by SuperMap SDX + to balance network and server loads and improve the overall performance of applications. After the file cache option is enabled, when the Application accesses the data stored in the Spatial Data library, it will first check whether there is a Newest Version of the corresponding data in the local cache library. If there is no corresponding Cache Data or the Cache Data is not the Newest Version, the data is read from the server side and the local Cache Data is updated, so that the local Cache Data can be read directly during the next access; If the local cache already has the Newest Version of the corresponding data, it is not necessary to request the data from the server through the network, but to read the local Cache Data directly to complete the display or analysis function. With this Solution, the database server load and network load can be significantly reduced, thereby significantly improving the overall performance of the Application.

Applicable conditions

For the Dataset generated by merging the data stored according to the standard scale (such as 1: 250,000 data, 1: 100,000 data, 1: 50,000 data, etc.) into the database, Mapsheet Index has an excellent effect and can provide very good query performance. Better Map Browsing speed can be achieved with the caching options provided by SuperMap.

Hint:
    The algorithm for
  • establishing Mapsheet Index has been greatly improved in 5.3. According to the size of the data, the time for establishing the index can be reduced by 4-10 times. For Dataset with a large number of records (more than 50,000), it is recommended to use 5.3 and later versions to create Mapsheet Index.
  • Mapsheet Index currently only supports point, line, surface, text and CAD Dataset in Database-type Datasource.
    • The engine types
  • supporting the establishment of Maps heet Index include SQLPlus, OraclePlus, KingBase, and MySQL.