BizTalk maps are graphical representation of XSLT to perform transformation between XML messages in simple & visual manner.
BizTalk Mapper is a tool that runs within the Microsoft Visual Studio environment. BizTalk Mapping can be used to create and edit maps, which are used for translating or transforming xml messages. Maps are used in orchestrations, receive port, and send port(s). Maps enable you to translate and to transform messages. Translation is the process of converting a message from one format to another format.
Part of BizTalk Mapper:
The following figure shows various parts of BizTalk Mapper within Visual Studio.
The functionality of each of the views is as follows:
Visual Studio Mapper Utility Ribbon. The BizTalk Server Mapper provides a utility ribbon to surface Mapper-related commands. The ribbon provides source schema information, toggle button for relevance view for source and destination schemas, toggle button to show or hide totally out of scope links, toggle switch to turn auto-scrolling on or off, button to pan the Mapper surface, controls to zoom in or zoom out, and the search text box. The following figure shows the utility ribbon you can see at the top of the grid page.
Source schema tree view. This is the tree view of the source message and is found on the left side of the main window
Destination schema tree view. This is the tree view of the target message and is found on the right side of the main window. The links that define the mapping lead into the destination schema tree view from the grid view, and ultimately from the source schema tree view.
Grid view. this view plays a critical role in the definition of maps, containing the links and functoids that control how data in a source instance message is transformed into an instance message that conforms to the destination schema.
The grid view can have multiple layers, called grid pages, allowing you to organize complex maps into logical subdivisions of mappings. Grid pages generally use more space than can be displayed at one time, and there are several effective ways to scroll within a grid page.Visual Studio Toolbox window. You use this view to display the functoids available for use in BizTalk maps, and as the source of the drag-and-drop operations to place functoids in a grid page. The functoids shown in the Toolbox are organized according to their categories
Property view: In this window, we can view and modify the properties of a selected object on the mapper grid or in the schemas. This is usually available on the right of the destination schema.
BizTalk World 