这个结合了散点图，个人觉得对探索性数据分析非常有用，用法在help文件里：
PKU Vis Group
November 24, 2009
1 Mouse Buttons
1.1 Left Button
Most frequently used button.
1. Click on the color palette with SHIFT pressed: Switch color space mode.
2. Double Click on plain region: Toggle on/off scatter point plot.
3. Click on dimension indicator: Select/Deselect corresponding dimension.
4. Click on dimension indicator with CTRL pressed: Select/Deselect multiple dimensions.
5. Double click on dimension indicator with CTRL pressed: Select all dimensions.
6. Drag dimension indicators with ALT pressed: Put multiple dimensions' information into an MDS plot.
Note for free hand sketching:
a. For selecting multiple points, the sketch circle must not close, but both ends need to be close.
b. CTRL pressed for union set and SHIFT pressed for difference set.
1.2 Middle Button
1. Click on the axis or point: Highlight one data point.
2. Scroll up/down: Change region width.
2 Keyboard Input
1. "R" & "r": Reset the program.
2. "Q" & "q": Reset all axes' position and lock their position. Need to press once again to unlock.
3. "X" & "x": Toggle on/off anti-aliasing.
4. "V" & "v": Toggle on/off scatter plot at pointed region.
5. "N" & "n": Restore simple scatter plot from an MDS plot.
6. "Page Up/Down": Change background curves' opacity.
7. "Home/End": Change point opacity.
feedback: pkuvis@pku.edu.cn
