I\'m trying to select a user-defined area and fill with 1s, preferably with mouse input. Any suggestion how? Thanks.
You'll need the Image Processing Toolbox to use roipoly
as Georg suggested.
If you don't have that, you could try creating a rubber band box using
rbbox
There's a good example in the help. You might need to fiddle with units depending on how you're displaying your data. Remember to click and hold, drag and release..
h=impoly;
This code helps you to select a closed polygon of the image.
The command
roipoly
does exactly what you're looking for.