added by zhangjun at 2011-2-16
Class: Map
Description dojo.require("esri.map");
Description dojo.require("esri.layers.agsdynamic");
If the first layer added to the map is an ArcGISDynamicMapServiceLayer, the map will take on the projection of this layer（如果第一个添加到map中的图层是ArcGISDynamicMapServiceLayer，map将使用这个图层的投影）.
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Class: GraphicsLayer
Description dojo.require("esri.layers.graphics");
A layer that contains one or more Graphic features（GraphicLayer 可以包含一个或者多个Graphic feature）. Each map contains a GraphicsLayer by default, accessible using the Map.Graphics property（每个map默认包含一个GraphicLayer，通过Map.Graphics属性可以访问默认的GraphicLayer）. Beginning with v1.4, you can create your own graphics layers and add them to the map. Graphics layers can be reordered within the group of graphics layers. However, the graphics layer in Map.Graphics is always on top（默认的GraphicLayer始终在顶部）. Also, all graphics layers are always on top of TiledMapServiceLayers and DynamicMapServiceLayers。
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Description dojo.require("esri.toolbars.draw");
Toolbar that supports functionality to create new geometries by drawing them:
points (POINT or MULTI_POINT), lines (LINE, POLYLINE, or FREEHAND_POLYLINE),
polygons (FREEHAND_POLYGON or POLYGON), or rectangles (EXTENT)（Draw是工具类，它支持通过画点线面生成新的几何形状的功能）. To edit
geometries of existing graphics, use the Edit
Toolbar. （编辑已经存在的graphics的几何形状，请使用Edit Toolbar）
Mouse behavior when drawing features
- For POINT, click to add a point.
- For MULTI_POINT, click to add points, double-click to add the last point of the multi-point.
- For POLYLINE and POLYGON, click to add vertices, double-click to add the last vertex.
- For FREEHAND_POLYLINE and FREEHAND_POLYGON, press mouse down where to start, draw the feature, then let go when finished drawing.
- For LINE, EXTENT, press mouse down where to start and let go where to end the feature
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Description Class added v2.0. dojo.require("esri.toolbars.edit");
Mouse behavior when editing features:
- To move a feature, once the Edit toolbar is activated with that feature, press down on the feature, drag it, then let go at the new location.
- To add a vertex to a polyline or polygon, click on a "ghost" vertices and move it to the new location.
- To delete a vertex from a polyline or polygon, right-click the vertex and select 'Delete Vertex' from the menu. Only valid for polylines with at least three vertices and polygons with at least four vertices.
- To rotate or scale a geometry click the handle and move to the desired location.
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