Making A Subset In Erdas Imagine 9.3

Introduction: A typical Landsat scene covers an area of about 185km by 185km.  At times, it makes sense to cut out a subset of this larger image to simplify your analysis and focus on the portion of the scene that is of primary interest. This is quite easy.

Procedure:  Start ERDAS Imagine. Select Viewer Type dialog box will open up.  Select the Classic Viewer and click OK.  In the Viewer window, go toFile-Open-Raster layer and select the image that you want to subset.

Three methods are available:

– Coordinates. Define the coordinates of upper left and lower right corners of a box

– Enquire box. Open the image to subset in viewer. Select the area to subset using an enquire box (Utility 􀃆 Enquire box) then click on enquire box. Move the box and enlarge it to include the area you want to clip.

– AOI (Area Of Interest). More complex shapes to be selected by using the AOI option once an input file has been defined

– To create an AOI open the image to subset in viewer, and draw a closed loop AOI (AOI 􀃆 Tools) using the create rectangle or polygon AOI tool. Save the AOI as an AOI layer.

In the Viewer window, go to Utility-Layer Info to see how many bands are in the image and decide which bands you want to include in your subset.

From the main ERDAS Imagine toolbar, Select Data Prep-Subset Image