**Bug fix: **
Two-dimensional plots with coords

Many of the two-dimensional plotting commands (other than
**plot**
itself) that are supposed to work with the
**coords**
option do not work in Release 5. This is because of bugs in
**changecoords**
in the
**plots**
package.

`> `
**with(plots):**

One of the bugs causes the following three commands to produce blank plots. This bug (among others) has been fixed in patchlevel 1 (for Windows). The EC1 patch is available from Maple (http://www.maplesoft.com/patches.html). Recently-purchased copies of Maple may already have the patch installed.

`> `
**changecoords(plot(x,x=0..10),polar);**

`> `
**pointplot([seq([1,Pi/10*i],i=0..19)],style=line,coords=polar);**

`> `
**implicitplot(x=y,x=0..1,y=0..1,coords=logcosh);**

There are still some bugs, even in patchlevel 1:
**contourplot**
does not work with coords, and
**plot**
fails with a coordinate system having parameters specified in functional style:

`> `
**contourplot(x-y, x=0..1,y=0..1,coords=polar);**

Error, (in plot/iplot2d) cannot convert to coordinate system, polar

`> `
**plot(1, x=0..1, coords=logcosh(2));**

Error, (in plot/adaptive) unknown optional argument, coords = logcosh(2)

To remedy these bugs, I have written a replacement for
**changecoords**
for two-dimensional coordinate systems, called
**changecoords2d**
. This function is part of the Maple Advisor Database library, and must be loaded before use by the command
**readlib(changecoords2d);**
. Then instead of making a plot with the
**coords**
option, you first produce the plot without the
**coords**
option and then call
**changecoords2d**
with the plot as first argument and the name of the coordinate system as second argument. Note that all other options (e.g.
**scaling**
,
**colour**
or
**axes**
) should be part of the first plotting command, not the
**changecoords2d**
.

`> `
**readlib(changecoords2d);**

`> `
**changecoords2d(plot(x,x=0..10,scaling=constrained),polar);**

`> `
**changecoords2d(pointplot([seq([1,Pi/10*i],i=0..19)],style=line,colour=blue),polar);**

`> `
**changecoords2d(implicitplot(x=y,x=0..1,y=0..1),logcosh);**

`> `
**changecoords2d(contourplot(x-y, x=0..1, y=0..1, axes=box), logcosh);**

`> `
**changecoords2d(plot(1, x=0..1), logcosh(2));**

**See also: **
__addcoords__
,
__changecoords__
,
changecoords2d
,
__coords__
,
patchlevel 1
,
__plot(coords)__
,
__transform__

**Maple Advisor Database, **
R. Israel 1998