Method of controlling map zoom through mouse wheel based on sharpmap

Abstract

The invention relates to a method for controlling map scaling through a mouse wheel based on a Sharpmap. The method comprises the steps that firstly, a Sharpmap library function is called to load a map to obtain Envelope of the current field of view; then a mouse wheel event is established to obtain a current screen position coordinate of a mouse cursor, and a Sharpmap coordinate transfer function is called to transfer the screen position coordinate into a geographical coordinate of the Sharpmap; then a scaling range of every time mouse rolling is determined and put into an idler wheel scaling formula to obtain a new field of view of the map; finally the Sharpmap library function is called to zoom the map into the new field of view to complete the scaling of the map. The method for controlling the map scaling through the mouse wheel based on the Sharpmap is simple, and fills up the blank that the Sharpmap lacks of mouse wheel scaling innovatively based on human vision needs, the display functions of the Sharpmap are improved greatly, and convenience and fluency of map operation are improved.

Description

technical field [0001] The invention relates to a technical field of GIS system development map zooming, and more specifically relates to a method for controlling map zooming through a mouse wheel based on Sharpmap, and its algorithm principle is adapted to the method for controlling map zooming through a mouse wheel developed by GIS. Background technique [0002] At present, the research and application of GIS in the fields of mineral resources development, environmental protection, transportation, geological disasters, medical and health, and national defense and military affairs continue to expand, and the demand for GIS-based system development in various fields continues to increase. At present, the mainstream GIS development methods include secondary development based on mature commercial software (such as ARCGIS, MapGIS, etc.), development based on open source GIS, and development from the bottom. Secondary development based on commercial software is expensive, the sy...

AI Technical Summary

Problems solved by technology

Since SharpMap was born in 2006, its performance and functions have been greatly improved under the improvement of researchers or GIS system developers from all over the world. It is done by the left button of the single mouse or by pulling the frame. Every time the map is zoomed, you need to click the toolbar button and the zoom range cannot be controlled by yourself. It lacks the function of controlling the zoom in and zoom out of the map by scrolling the mouse, which is necessary for the actual operation. brought great inconvenience

Commercial software such as ArcGIS, MapGIS, and AutoCAD all realize the function of controlling map zoom through the mouse wheel, but excellent open source GIS software such as QGIS, GeoServer, and Mapserver, some do not have this function, and some have this function. The effect of zooming on the map cannot be well adapted to the visual needs of the human eye. During the zooming process, the position of the center of gravity of the mouse cursor is prone to shift, resulting in visual difficulties. However, large-scale commercial GIS software systems are huge and expensive, and most of the functions are in professional models. GIS system does not need

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