The most commonly used geometries in map drawing are points, lines, polygons, and text. The Features tab provides functionality for creating various geometries on maps, including: point feature drawing, line feature drawing, polygon feature drawing, and text annotation.

All geometry drawing operations must be performed with editable layers. While multiple layers can be set as editable simultaneously, new point, line, polygon or text features will only be created in the currently selected layer. Therefore, to create new features in a specific layer, you must first click the corresponding layer in the layer manager to set it as the current layer.

The following concepts related to feature drawing are explained below:

Object Overview

Object: Also called geometry, representing the abstract expression of discrete spatial entities in GIS. Each object possesses its own attributes and behaviors. In SuperMap, some objects can be created directly while others require conversion.

• Single Object: Refers to an individual object, which can be a simple object, complex object, compound, or sub-object.
• Sub-object (Part): The constituent unit of simple and complex objects. A simple object consists of one sub-object (itself), while a complex object contains two or more sub-objects.
• Simple Object: An object composed of a single sub-object (itself).
• Complex Object: An object containing two or more sub-objects of the same type.
• Compound Object: Specifically refers to objects generated through combination operations in CAD layers. Compound objects do not have sub-objects.
• Parametric Object: Geometry created through primary parameters in continuous operations, as opposed to regular geometries defined by key point coordinates. For example, a parametric circle is precisely defined by center coordinates and radius, while a regular circle is formed by discrete arc points.

Angle Specification in Feature Drawing

• Angle Direction: All angles in the application follow counterclockwise orientation.
• Start Angle: The angle between true north direction and another edge when drawing objects.

Parametric Drawing Explanation

When drawing lines, parametric drawing automatically splits original and new objects at intersections to create multiple line objects. This feature can be activated by clicking the Parametric Drawing button in the Feature Drawing group under the Features tab, or by using the Shift+P shortcut.

• Coordinate Input: Draw points, lines, polylines, curves, circles, and polygons by specifying coordinate parameters including start points, midpoints, vertices, and endpoints.
• Length Input: Create lines, polylines, polygons, sectors, circles, and arcs by defining length parameters such as line length, side length, radius, and diameter.
• Angle Input: Determine object orientation and start angles through angular parameters.

Parametric Objects

Shift Key Functionality

Using the Shift key during drawing operations enhances efficiency:

• Line Drawing: When creating lines with length and angle parameters, holding Shift restricts drawing to horizontal, vertical, or 45-degree directions.
• Rectangle/Rounded Rectangle Drawing: Creates squares with equal width and height when using width/height parameters with Shift.
• Ellipse Drawing: Generates perfect circles when drawing inscribed ellipses with Shift.

A Key Functionality

Press the A key during map drawing to switch mouse mode to pan navigation, indicated by cursor.

To resume drawing after switching to pan mode:

• Press A again
• Right-click mouse
• Press Esc

Q Key Functionality

Press Q when drawing lines or polygons to enable snap function. This automatically aligns mouse movements to existing object boundaries, preventing topology errors.

• First Q press: Enable snap
• Second Q press: Disable snap