Method for hierarchical drawing of map layers

Abstract

The invention discloses a method for hierarchical drawing of map layers. The method comprises the following steps of adding an attribute field into data to display showscale attribute of a scale; setting pixel resolution displayed by a full-map drawing panel; judging whether the showscale attribute of a current element has been set or not; when the showscale attribute is not set, drawing a map according to a current pixel ratio, and judging whether the element of the drawn map is smaller than one pixel or not; when the element is smaller than one pixel, using the showscale attribute of the element with the same element coordinate and the pixel less than 1 as a current pixel value; when the element is not smaller than one pixel, judging whether the element of the drawn map is equal to one pixel or not; when the element of the drawn map is equal to one equal, completing the data pre-processing. The method for hierarchical drawing of the map layers has the advantages that the stress of the frontend display is well relieved; for a mechanism of rendering the map layers in real time by the hierarchical drawing, the computation load is reduced by setting the attributes, and the real-time rendering can be performed according to the user requirements.

Description

technical field [0001] The invention belongs to the technical field of computer software, and in particular relates to a hierarchical drawing method for layers. Background technique [0002] With the development of network technology, the application of geographic information system (WebGIS) in the network environment is becoming more and more extensive. For example, Google maps and MapBar maps in daily life have widely affected the lives of the public. Different from the traditional WebGIS method in the past, these modern maps no longer dynamically generate map pictures on the client side (that is, every time the client generates a new map request, the server needs to regenerate the map picture and send it to the client), but uses Map cache service mechanism. Since GoogleMap launched the Tile Map Image (tile map) method, this map cache service mechanism has become a key technology to improve the performance of map application systems. In map caching technology, network tr...

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Problems solved by technology

[0006] For the above four steps, some manufacturers can already provide cache service updates in a local area, while others cannot; when setting the map range, setting the range manually is not as accurate as automatically calculating the range by computer; in service association data Manual operation is also prone to error

[0007] Based on the above reasons, more and more domestic manufacturers have begun to realize the importance of hierarchical map drawing and real-time rendering of maps. Some domestic manufacturers have begun to study the function of layer-by-layer map drawing. There are certain limitations in the patterning of the data processing process, and its automatic cache update process

However, foreign manufacturers, especially some platform providers, still have their foothold abroad and have not fully realized the strong actual demand of the Chinese market, so they still use manual methods to update the map cache

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