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(1) element class: a set of elements with the same attributes and the same spatial type. In the system, element classes refer to elements under the vector dataset directory in the layers management bar.
(2) dataset: a set of spatial element classes with the same projection and with the same scale. A dataset package contains multiple element classes.
(3) Image Library: a spatial database used to manage spatial datasets. The image library can contain multiple datasets.
(4) layer: A layer refers to a spatial data table that is stored in a database but does not belong to any dataset. It does not belong to the image library, but can be used as the data source of the element class in the data set. In the system, a layer refers to the free layer under the layer directory in the layer management bar.
Shows the relationship between them: