3. Making a Subset

A subset is a section of a larger downloaded image. Since satellite data downloads usually cover more area than you are interested in and near 1 GB in size, you can select a portion of the larger image to work with. To do this:

1. Open an image.
2. If you know the latitude and longitude of your location you can move the cursor to that location which is indicated in the top menu line of the image. If the image is set as lines and columns, you can change the pull down menu at the top of the image to lat-long.
3. Place the mouse on the upper left corner of the area on the image you would like to include in a subset of this image. Click, hold and drag the mouse over the desired area. A rectangle will be created. To redo, just re-select your rectangle.
4. Click Processor, Reformat, Change Image File Format. Click Ok in next screen.
5. Rename your file and extension .tif Click save. Wait.
6. Close the image and choose file and open your subset. Click ok twice.