QGIS Shape Tools Plugin

Shape Tools has the following tools that are installed in the Vector menu or can be accessed from the toolbar.

Contents

Create Shapes Create Shapes

Examples

Ellipses, lines of bearing, pie wedges, multi-sided polygons, stars, ellipse roses, hypocycloids, polyfoils, epicycloids, and hearts can be created from parameters in the layer data or from default parameters in the Create Shapes tool. Note that the layer created is a memory layer and will not be saved with the QGIS project. You need to manually save the layer or use the Memory Layer Saver plugin.

All of the shapes are created centered around the input points. Common elements are:

Ellipse

XY to Line

Select a points vector layer and an output layer name or use the default name. Then select the specific ellipse parameters. The semi-major axis of the ellipse runs along the orientation axis. The orientation the axis is measured in degrees in a clockwise direction from the north line. Units of measure for semi-major, and semi-minor lengths are defined by Axis units of measure.

If a field in the layer represents the semi-major axis, semi-minor axis, or orientation of axis, then the field can be selected and the data from the layer will be used, otherwise the default values will be used.

Line of Bearing

Bearing is the angle measured in degrees, in a clockwise direction from the north line. A line of bearing is the line drawn from a starting point in the direction of the bearing for the selected distance. The line of bearing uses geodesic math to find the shortest path and is accurate along the Earth's surface.

Pie Wedge

The pie wedge focal point starts at the point layer's geometry extending out to the specified radius. It starts at the Starting bearing going in a clockwise direction to the Ending bearing. The pie wedge can either be defined from the point vector layer data fields or from the Default parameters.

Polygon

Create an N-sided polygon centered on the vector point. The vertices of the polygon lie on a circle of the default radius.

Star

Create an N-pointed star with the outer vertices located on a circle defined by the outer radius. The inner vertices are located along the circle defined by the inner radius. One of the radius' can be negative which gives an interesting shape.

Ellipse Rose

Create an N-petal rose. The distance from the center to the outer petals are defined by the radius.

Hypocycloid

Create an N-pointed hypocycloid. A hypocycloid is defained as the curve traced by a point on the circumference of a circle that is rolling on the interior of another circle. The distance from the center to the outer cusps are defined by the radius.

Polyfoil

Create an N-leafed polyfoil. The distance from the center to the outer leafs are defined by the radius.

Epicycloid

Create an N-leafed epicycloid. The distance form the center to the outer edge is defined by the radius.

Heart

Create a mathematical heart which fits within the circle defined by its radius.

XY to Line XY to Line

This creates geodesic lines based on starting and ending coordinates in each table record. One of the coordinates can be from a point layer geometry or both can come from the table data itself where each record has a start x-coordinate, start y-coordinate, and an end x-coordinate and end y-coordinate.

XY to Line

Input Layer - This can either be a points layer of a simple table. For example a CSV file containing starting and ending coordinates could be imported using the importer Add Delimited Text Layer... from the menu Layer->Add Layer->Add Delimited Text Layer... From this dialog box the user can specify one of the coordinates for the layer's geometry or No Geometry can be used. Both types of layers will be visible to XY to Line.

Output Points Layer Name - Name of the points layer that will be created in QGIS. It is automatically generated from the Input Layer name. It can contain the starting point, ending point, both points, or no points in which case it will not be created.

Output Line Layer Name - Name of the line layer that will be created in QGIS. It is automatically generated from the Input Layer name.

Input Coordinate CRS - CRS of the input coordinates. Note that if Use the Layer's geometry is specified this must match both the layer's geometry CRS as will as the table's data CRS.

Output Layer CRS - CRS of the output line and point layers.

Line Type - 1) Geodesic creates a highly accurate shortest path between two points. 2) Great Circle creates a Great Circle arc between the two points. 3) Simple Line creates a non-geodesic straight line between the two points.

Starting Point - Specify whether to use the Layer's geometry (not available for tables) or to specify the Start X Field and Start Y Field from the layer's fields.

Ending Point - Specify whether to use the Layer's geometry (not available for tables) or to specify the End X Field and End Y Field from the layer's fields.

Show Starting Point - If checked the output point layer will include an entry for the starting point.

Show Ending Point - If checked the output point layer will include an entry for the ending point.

Break lines at -180, 180 boundary for better rendering - Depending on the QGIS projection when lines cross the international date line, strange behavior may occur. Checking this box breaks the line at the -180, 180 boundary in a way that it displays properly.

If neither Show Starting Point nor Show Ending Point are checked, then a point layer will not be created.

Geodesic Shape Densifier Geodesic Shape Densifier

Densify a line or polygon vector layer by adding geodesic points inbetween individual line segments when its length is too great. This gives it a nice smooth curved appearance. For line vectors a geodesic line can be drawn between just the beginning and ending points.

The distance between two points before adding additional vertices is set from the Settings menu.

Geodesic Shape Densifier

The following shows the before and after results of running this function on a polygon layer.

Geodesic Polygon

This function can also be accessed from the Processing Toolbox.

Processing Toolbox

Geodesic Measure Tool Geodesic Measure Tool

This provides the ability to measure distances using geodesic (shortest path) algorithms. The results returned are the same as those used by Google Earth and makes for a nice baseline of distances. It also includes the heading from the first point to the second and a heading from the second point to the first. The units are in degrees. The units of distance can be meters, kilometers, feet, yards, miles, and nautical miles. Simply click on the Geodesic Measure Tool icon and start clicking on the map.

Geodesic Measure Tool

The Save to Layer button will create a Measurement layer that contains the distance and by default the distance label will be displayed.

Geodesic Measure Tool

By right-mouse clicking on the Measurement layer and selecting Open Attribute Table, the following attributes are available for each measured line segment; label, value, units, heading_to, and heading_from.

Geodesic Measure Tool

Azimuth, Distance Tool Azimuth, Distance Tool

This tool works on point and line vector layers and is enabled when they are selected and in edit mode. In either case this dialog box is displayed when the tool is enabled and a point on the map is clicked on.

Azimuth, Distance Tool

Azimuth is in degrees and distance is in the selected Distance units of measure. The following is how it interacts on point and line layers.

Settings

The settings dialog box can be accessed from the Shape Tools menu Vector->Shape Tools->Settings. The following are the parameters that can be configured.