Q: Why a layer in a map has no data to display even when the number of records of the corresponding dataset is not zero?

A: Possible reasons are as follows:
1. You have specified minimum and maximum visible scales for the layer and the scale of the current map is not within the specified range. You can clear the visible scale range settings to display the data in the layer. 
2. There are too many vertices for objects. You can modify the maximum number of vertices for visible objects through [Map Properties]—[Basic]—[Show Settings]—[Visible Vertices]. 
3. The size of objects in the dataset is too small, which takes up less than four pixels on the screen. By default, small objects will not display. You can modify the size of minimum visible objects through changing Min Object Size in the Layer Properties window to 0, and then refreshing the map.