readCartesian

(To be removed) Read laser scan ranges in Cartesian coordinates

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readCartesian will be removed in a future release. Use rosReadCartesian instead. For more information, see ROS Message Structure Functions.

Syntax

cart = readCartesian(scan)
cart = readCartesian(___,Name,Value)
[cart,angles] = readCartesian(___)

Description

cart = readCartesian(scan) converts the polar measurements of the laser scan object, scan, into Cartesian coordinates, cart. This function uses the metadata in the message, such as angular resolution and opening angle of the laser scanner, to perform the conversion. Invalid range readings, usually represented as NaN, are ignored in this conversion.

example

cart = readCartesian(___,Name,Value) provides additional options specified by one or more Name,Value pair arguments. Name must appear inside single quotes (''). You can specify several name-value pair arguments in any order as Name1,Value1,...,NameN,ValueN.

example

[cart,angles] = readCartesian(___) returns the scan angles, angles, that are associated with each Cartesian coordinate. Angles are measured counterclockwise around the positive z-axis, with the zero angle along the x-axis. The angles is returned in radians and wrapped to the [ –pi, pi] interval.

Examples

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Open Live Script

Connect to ROS network. Subscribe to a laser scan topic, and receive a message. 

rosinit('192.168.17.129')
Initializing global node /matlab_global_node_40737 with NodeURI http://192.168.17.1:56343/

sub = rossubscriber('/scan');
scan = receive(sub);

Read the Cartesian points from the laser scan. Plot the laser scan.

cart = readCartesian(scan);
plot(cart(:,1),cart(:,2))

Shutdown ROS network.

rosshutdown
Shutting down global node /matlab_global_node_40737 with NodeURI http://192.168.17.1:56343/
Open Live Script

Connect to ROS network. Subscribe to a laser scan topic, and receive a message.

rosinit('192.168.17.129')
Initializing global node /matlab_global_node_12735 with NodeURI http://192.168.17.1:56572/

sub = rossubscriber('/scan');
scan = receive(sub);

Read the Cartesian points from the laser scan with specified range limits. Plot the laser scan.

cart = readCartesian(scan,'RangeLimit',[0.5 6]);
plot(cart(:,1),cart(:,2))

Shutdown ROS network.

rosshutdown
Shutting down global node /matlab_global_node_12735 with NodeURI http://192.168.17.1:56572/

Input Arguments

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'sensor_msgs/LaserScan' ROS message, specified as a LaserScan object handle.

Name-Value Arguments

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Specify optional pairs of arguments as Name1=Value1,...,NameN=ValueN, where Name is the argument name and Value is the corresponding value. Name-value arguments must appear after other arguments, but the order of the pairs does not matter.

Before R2021a, use commas to separate each name and value, and enclose Name in quotes.

Example: 'RangeLimits',[-2 2]

Minimum and maximum range for a scan in meters, specified as a 2-element [min max] vector. All ranges smaller than min or larger than max are ignored during the conversion to Cartesian coordinates.

Output Arguments

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Cartesian coordinates of laser scan, returned as an n-by-2 matrix in meters.

Scan angles for laser scan data, returned as an n-by-1 matrix in radians. Angles are measured counterclockwise around the positive z-axis, with the zero angle along the x-axis. The angles is returned in radians and wrapped to the [ –pi, pi] interval.

Version History

Introduced in R2019b

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See Also

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