GIS geographic information system, are mainly used for processing and location technology, the basic functions have a zoom in and out,

Declared himself is in the circle is a problem encountered in the process of

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Above can see is a set of code can perform area measurement, so that draw round code method is the same, but at the time of execution error





"Events" is null in the error, but all calls are effective in the event, but is always prompt events is null,





Later after many times after debugging, found in add controls and activate the controls two code position moves up and down, draw circles on the map success



Personal emotion at the time, come to the conclusion: code execution order is very important, sometimes a short code will also have unexpected effect

CodePudding user response:

This is a plug-in produce conflict, as long as or use the method to adjust the position of the plugin

CodePudding user response:

Thanks to friends and friends