ERDAS 1 INTRODUCTION TO ERDAS IMAGINE GEO 420

ERDAS 1: INTRODUCTION TO ERDAS IMAGINE GEO 420

Goals: 1. Display raster image using panchromatic, normal & false color. 2. Use zoom tool/buttons to properly display image and inquire cursor to identify pixel locations and digital numbers. 3. Display image automatically scaled with DN’s stretched from 0 -255, or with natural spectral variation. • Use histogram to view spectral variability and frequency/proportion of DN’s within each class. 4. Perform a linear contrast stretch 5. Measure distances and areas within an image.

1. Displaying an Image • No stretch image • View/Edit Image Metadata

• Lanier. img - Landsat Thematic Mapper (TM) image that has 7 wavebands of information with 512 rows and columns of raster information. • You have displayed a False Color Composite which sends Near Infrared (NIR) Light in TM Band 4 to the Red color gun, Red Light in TM Band 3 to the Green gun, and Green Light TM Band 2 to the Blue gun. • Display Options settings - No Stretch – so it looks dark. • Home > Metadata Icon and choose View/Edit Image Metadata - gives you all of the info Imagine has on this image (number of layers is 7 for TM, min and max DN values, the Measurement Units, and the Projection (if any), etc.

2. Inquire Cursor Utility

Google Earth Capabilities

3. Histograms Type of Image Enhancement: Contrast manipulation – contrast stretching of histogram distn

4. Stretching an image Swipe

5. Measurements

6. Spectral Profiles • Band 1 = blue (high due to scattering) • Band 2 = green • Band 3 = red • Band 4 = near infrared • Band 6 = thermal

6. Spatial Profiles

Landsat 7 and TM & ETM+ Characteristics: Band Spectral Range(µm) Resolution(m) 1 . 45 to. 51 30 2 . 525 to. 605 30 3 . 63 to. 690 30 4 . 75 to. 90 30 5 1. 55 to 1. 75 30 2. 09 to 2. 35 30 10. 40 to 12. 5 (thermal) 60 7 6

NDVI