2.1. Turtles

Turtles are the kind of agents you will use most of the time. This tutorial will walk you through the commands that permit you to create and manipulate turtles in your model.

We will also cover the properties of turtles, which are the attributes that define their behavior and appearance. Turtles can have different shapes, colors, and sizes, and you can use these properties to represent different types of agents in your model.

2.1.1. Creating Turtles

To create turtles in your model, you can use the create-turtles command. This command creates a specified number of turtles and assigns them random properties. For example, the following command creates 10 turtles:

create-turtles 10

This command creates 10 turtles with random properties. You can also specify the properties of the turtles when you create them. For example, the following command creates 10 turtles with a specific color and shape:

create-turtles 10 [
  set color red
  set shape "circle"
]

This command creates 10 turtles with the color red and the shape of a circle. You can also use the set command to change the properties of turtles after they are created. For example, the following command changes the color of all turtles to blue:

ask turtles [
  set color blue
]

2.1.2. Moving Turtles

To move turtles in your model, you can use the fd (forward) and bk (backward) commands. These commands move turtles a specified distance in the direction they are facing. For example, the following command moves all turtles forward 10 steps:

ask turtles [
  fd 10
]

This command moves all turtles forward 10 steps. You can also use the rt (right turn) and lt (left turn) commands to change the direction of turtles. For example, the following command turns all turtles right 90 degrees:

ask turtles [
  rt 90
]

This command turns all turtles right 90 degrees. You can also use the set heading command to set the direction of turtles to a specific angle. For example, the following command sets the heading of all turtles to 45 degrees:

ask turtles [
  set heading 45
]

2.1.3. Changing Turtles’ Properties

To change the properties of turtles, you can use the set command. For example, the following command changes the color of all turtles to green:

ask turtles [
  set color green
]

This command changes the color of all turtles to green. You can also use the set command to change other properties of turtles, such as size and shape. For example, the following command changes the size of all turtles to 2:

ask turtles [
  set size 2
]

This command changes the size of all turtles to 2. You can also use the set command to change the shape of turtles. For example, the following command changes the shape of all turtles to a square:

ask turtles [
  set shape "square"
]

This command changes the shape of all turtles to a square. You can also use the set command to change other properties of turtles, such as color and heading. For example, the following command changes the color of all turtles to red:

ask turtles [
  set color red
]

This command changes the color of all turtles to red. You can also use the set command to change other properties of turtles, such as size and shape. For example, the following command changes the size of all turtles to 2:

ask turtles [
  set size 2
]

This command changes the size of all turtles to 2. You can also use the set command to change other properties of turtles, such as color and heading. For example, the following command changes the color of all turtles to red:

ask turtles [
  set color red
]

The table below contains all properties that you can set for turtles:

Property	Description
who	The unique identifier of the turtle. It is automatically assigned by NetLogo and cannot be changed.
color	The color of the turtle. Can be set to any color name or number.
heading	The direction the turtle is facing. Can be set to any angle in degrees.
xcor	The x-coordinate of the turtle’s position in the world. Can be set to any number.
ycor	The y-coordinate of the turtle’s position in the world. Can be set to any number.
shape	The shape of the turtle. Can be set to any shape name defined in the model.
label	The text label displayed above the turtle. Can be set to any string.
label-color	The color of the turtle’s label. Can be set to any color name or number.
breed	The breed of the turtle. Can be set to any breed defined in the model.
hidden?	A boolean value indicating whether the turtle is hidden or visible. Can be set to true or false.
size	The size of the turtle. Can be set to any number.
pen-size	The size of the turtle’s pen. Can be set to any number.
pen-mode	The mode of the turtle’s pen. Can be set to up or down.