Exercise 3: Importing & subsetting imagery

D. Meyerdmeyer@usgs.gov

E. Woodwoodec@usgs.gov

Import a Landsat TIFF file into Imagine

• Click on “Import” button on the Imagine ToolBar

• Navigate to both input AND output folders before selecting input file name: 5032028009919210_REFL.TIF (July 2006 scene south of Bismarck– Otherwise, the output file name box is erased– If asked “build pyramids”, say “yes”

• Click “okay” in “import TIFF” window• In the viewer, display bands 5, 4, 3 as RGB

Output “srock_99.img” in Exercise 3 results folder

Subset an image• Click “AOI” in the Viewer menu – select

“tools” in the drop down menu• Select “create rectangle” button in the AOI

tool palette• Drag rectangle over area to be sub-setted.• In the Viewer menu, under “File -> Save”,

select “Save AOI layer as…”• Save the file “srock_99.aoi in Exercise 3

results folder

Place output in Exercise 3 results file

Subset an image (con’t)• In the Imagine toolbar, click on the “DataPrep”

tab, the “subset image” button• In the “subset” window under “Input File”

navigate to the folder with imported image –srock_99.img (output file type: “imagine”

• Under “Output File”, navigate to exercise 3 results folder, enter “srock_99_subset.img” as output file

• Hit “AOI” button at bottom of window, then “viewer”

• Click “Okay”, then view the result in the Viewer

Subset a new image using previous AOI

• Click on “DataPrep” then “subset image” from Imagine toolbar.

• Input: 5032028000619510_refl.img (2006 TM scene)

• Create output “srock_06_subset.img” in the results folder

• Click “AOI” button in “subset” window• Select “AOI File” and navigate to the previously

saved “srock_99.aoi” file (click OK)• Click “Okay” in the subset window and view the

output in the Viewer.

Use srock_99.aoi in Exercise 3 results folder

Subset a new image using previous AOI (con’t)

• To compare the srock_06 image with srock_99 image: in the viewer (with the 2006 scene still displayed), “File -> Raster Layer”

• Navigate to the srock_199.img file, and select “Raster Options” tab, unclick “clear display” and display bands 5,4,3 as red, green, blue

Subset a new image using previous AOI (con’t)

• Select an area along the river to zoom into with the zoom tool on the Viewer task bar

• In the zoomed view, right click in the viewer window and select “swipe”

• Use the swipe tool (horizontal orientation) to compare the 1999 and 2006 images.

• Discuss the differences you see that could be related to climate

Subset using the Spatial Modeler• Permits sub-subsetting inside larger

processes• Select “Modeler” on the Imagine taskbar• Select “Model Maker” on the• Create the model as shown in the diagram

by clicking on the relevant symbols in the model maker tool and dragging them into the “new model” window– “stack” symbol represent input /output files, circle represents processes– Arrows connect files to processes, click and drag

Subset using the Spatial Modeler (con’t)

• Click on the input stack in the “new model” window and navigate to the GeoTIFF 5032028008921210_REFL.TIF image., For output stack: “srock_06m.img” (“delete if it exists”)

• Click on the process circle and click on the top entry under “available inputs” (process all bands)

Subset using the Spatial Modeler (con’t)

• Under “Model” (“new model” window click on “Area of interest” and navigate to the “srock_99.aoi” file as before (click okay).

• Under “model” (etc.) “set window” to “file” and use the srock_99_subset.img to clip the window to the subset size.

• Click on the lightning bolt in the “new model” window, and view the result when done.

Compare 1999 to 1989