Despite the fancy title (named after the French philosopher and mathematician René Descartes 1596-1650), the Cartesian co-ordinate system is the standard co-ordinate system. The position of a point can be described by its distance from two axes, X and Y. This results in a simple point description using two numbers separated by a comma e.g. 34.897,45.473.
In the example on the right the point described lies 34.897 drawing units to the right of the Y axis and 45.473 drawing units above the X axis. The first value (34.897) is known as the X co-ordinate because it's value is measured along the X axis. The second value is known as the Y co-ordinate because it's value is measured along the Y axis.The X and Y axes are two lines of infinite length which intersect
at the origin point. The co-ordinate value of the origin point is always 0,0. When viewed in plan the X and Y axes are always perpendicular to one another with the X axis in a horizontal position and the Y axis in a vertical position (See illustration). X co-ordinate values become negative to the left of the Y axis and Y co-ordinate values become negative below the X axis. All co-ordinate values (both X and Y) are negative in the lower left hand quadrant and positive in the upper right hand quadrant. Normally we try to work in the positive quadrant. Although this is not essential for AutoCAD to operate, it does tend to make life easier because we don't need to worry about negative numbers.
AutoCAD allows you to use co-ordinates to draw objects rather than using pick points. For example you could draw a line like this:
From point: 34.897,45.473
To point: 54.896,65.395
To point:
(to end)
This sequence draws a line between the two co-ordinate points specified. Note that if you enter a co-ordinate that is off the screen the line will still be drawn to the required point. You will then need to zoom out in order to see the whole line. You can also start the Line command by clicking
on the Draw toolbar or from the pull-down menu (Draw
Line).
In the example on the right the point described lies 34.897 drawing units to the right of the Y axis and 45.473 drawing units above the X axis. The first value (34.897) is known as the X co-ordinate because it's value is measured along the X axis. The second value is known as the Y co-ordinate because it's value is measured along the Y axis.The X and Y axes are two lines of infinite length which intersect
at the origin point. The co-ordinate value of the origin point is always 0,0. When viewed in plan the X and Y axes are always perpendicular to one another with the X axis in a horizontal position and the Y axis in a vertical position (See illustration). X co-ordinate values become negative to the left of the Y axis and Y co-ordinate values become negative below the X axis. All co-ordinate values (both X and Y) are negative in the lower left hand quadrant and positive in the upper right hand quadrant. Normally we try to work in the positive quadrant. Although this is not essential for AutoCAD to operate, it does tend to make life easier because we don't need to worry about negative numbers.
AutoCAD allows you to use co-ordinates to draw objects rather than using pick points. For example you could draw a line like this:
Command Sequence
Command: LINEFrom point: 34.897,45.473
To point: 54.896,65.395
To point:
(to end)This sequence draws a line between the two co-ordinate points specified. Note that if you enter a co-ordinate that is off the screen the line will still be drawn to the required point. You will then need to zoom out in order to see the whole line. You can also start the Line command by clicking
on the Draw toolbar or from the pull-down menu (DrawLine).
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