Not sure if it has been mentioned before, cannot find it with search
of Shape markers.
First let's see the usage of Shape markers.
chm=
<marker type>,<color>,<data set index>,<data point>,<size>,<priority>|
...
<marker type>,<color>,<data set index>,<data point>,<size>,<priority>
The trick is, if give the <data point> value as -1.0, the marker will
be added to all points of that set of data. One doesn't need to
specify very point's marker if he want to apply the marker to the
whole set.
Extremely useful when you find your URL is exceeding the length limit
of HTTP URL.
Enjoy.
Shaoxuan
1 message in com.googlegroups.google-chart-apiUndocumented trick of Shape markers