
Downloading satellite imagery from https://earthexplorer.usgs.gov
How to unzip satellite imagery files. June 19 2016, June 12 2016, and August 4 2015 data have been uploaded below. This way you can use the same data sets that I will be using throughout the course.
Open Landsat 8 imagery in ENVI by selecting file, open as, and geo tiff with metadata, then load the text document describing the unpacked zip to display the images.
Explore how to manage Landsat 8 data with the data manager, display spectral bands in color, and use red, green, and blue band displays to reveal features.
Save ENVI files by selecting file save as and choosing formats like ENVI, JPEG, ERDAS Imagine, or TIFF, with options for spectral and spatial subsets and georeferenced with GPS coordinates.
Cursor Value, Crosshairs, Select, Pan, Fly, Rotate View, Zoom, Fixed Zoom In, Fixed Zoom Out, Zoom to Full Extent, North Up,
Arbitrary Profile, Spectral Profile, Scatter Plot Tool, Region of Interest (ROI) Tool, Feature Counting, "Go To" Box, Brightness, Contrast
Stretching, Reset Stretch Type, Sharpen, Transparency, Mensuration, Portal, View Blend, View Flicker, View Swipe, Different Views
Edit ENVI header to adjust image metadata, set band loading and display, add data ignore value to remove no data areas, and apply a default stretch for clearer Landsat imagery.
Explore the ENVI spectral library to compare mineral and vegetation signatures, import your own spectral signature, create custom folders, and export results as images or PDX for material identification.
Convert digital numbers to top of atmosphere radiance via radiometric calibration, ignore zeros to exclude no data, then apply atmosphere correction in ENVI to obtain bottom of atmosphere reflectance.
Perform flash atmospheric correction on Landsat 8 radiance to obtain surface reflectance from top-of-atmosphere values; apply band math to divide by 10000.
Crosshair data values, Spectral Profile
Draw a region of interest (roi) in ENVI by a rectangle to isolate fields. Use subset data to save a focused field image.
Learn to isolate water in an image by spectral thresholding in ENVI, using near infrared reflectance, histograms, and color-coded region of interest that saves for later.
Master ENVI basics through Lab 1, practicing core ENVI tools with downloadable data, zip handling, and guided exercises, plus example questions and solutions for practice.
Create a water mask in ENVI from an atmospherically corrected Landsat 8 image, saving only water pixels with a near-infrared threshold for lake studies like chlorophyll or algae blooms.
Isolate clouds with a threshold in the coastal aerosol band of Landsat 8, preview selection, save as a cloud mask, and apply an inverse mask to reveal land and water.
Apply band ratios in ENVI to create a simple vegetation index (near infrared over red), visualize with raster color slices, and customize color schemes to compare vegetation levels.
Use ENVI's MDVIP to compute NDVI on a Landsat 8 subset, save the VI fields, set red band 4 and near-infrared 5, and display vegetation health with red-to-green colors.
We will be doing a change detection difference map between a subset of June 19 2016 image and the August 2015 Image. In a previous assignment you should have already preformed radiometric calibration and FLAASH atmospheric corrections on the August 4 2015 Image. Otherwise FLAASH atmospherically corrected August 4 2015 Image is provided below in a zip file.
We will be preforming a seamless mosaic between the June 19 2016 Landsat 8 Image and the June 12 2016 Landsat 8 Image to create once large image. In a previous assignment you should have radiometrically and atmospherically corrected the June 12 2016 Image. Otherwise the atmospherically corrected June 12 2016 image is attached below in a zip file for downloading.
Explore unsupervised classification in ENVI by clustering pixels with iso data or k-means, then compare to supervised classification that uses training data to label water and fields.
A second way to preform unsupervised classification of your image
Train data guides a supervised classification of a Landsat 8 image in ENVI, defining water and fields classes with multiple training samples.
Project start to finish using ENVI tools we have learned so far. Simple way to look for surface algae blooms in a lake.
Convert Landsat 8 thermal data to kelvin surface temperature using radiometric calibration and brightness temperature in ENVI, compare lake and land temperatures, and explore band math to Fahrenheit or Celsius.
Learn to compare before and after tsunami images using the image change workflow, analyze vegetation index differences, apply auto thresholding, and export results as ENVI and shapefile outputs.
Explore thematic change detection in ENVI by comparing the same scene's pre-Katrina and post-Katrina classification images to identify changes and export results as a shape file.
Construct a Landsat time series from 1975 to 2014 to monitor urban expansion and vegetation changes, using calibrated, atmospherically corrected images and an optimized soil adjusted vegetation index.
Explore reprojection, registration, and mosaicking of remote sensing images using ENVI software, with exercises and version-specific instructions for accurate analysis.
Create an attribute image for supervised classification by combining spectral, height, and vegetation attributes into a layer stack in ENVI, then use an enhanced vegetation index to distinguish surface features.
Explore hyperspectral analysis and visualization in ENVI, selecting red, green, and blue bands, compare spectral signatures with a library to identify minerals using continuum removed for clearer discrimination.
Learn to preprocess Avars data and convert it to surface reflectance using flash atmosphere correction, handle scale factors, edit bad bands, and prepare for hyperspectral analysis.
Analyze hyperspectral imagery with ENVI to identify vegetation stress from insect damage, using spectral indices like the moisture stress index and the forest health tool to map stressed areas.
Spectral Angle Mapper (SAM) and Spectral Feature Fitting (SFF)
Install MapTiler to load satellite imagery as a scalable base map. Download, install via the desktop wizard, accept the terms, then load satellite images for web applications.
Pan sharpen Landsat 8 to a 15-meter color image using red, green, blue bands from a 30-meter base, then save as a native ENVI file for a high-resolution base map.
Convert the native file to MBTiles format for use with map tiler. Apply a 2 percent linear stretch and set 0–255 scales for a zoomable, tiled output.
Are you currently enrolled in my Fundamentals of Remote Sensing and Geospatial Analysis course and want to take your remote sensing knowledge to the next level?
Are you already familiar with the field of remote sensing and want to learn how to process images?
The next step for you is to gain proficiency in remote sensing data analysis using ENVI software!
Go from zero to hero in remote sensing satellite image processing!
My course provides a complete foundation to carry out practical and real life remote sensing image analysis processes using ENVI software. ENVI is the most widely used remote sensing and image analysis program within Industry and Research. In this course you will be using actual images and data from Landsat 8 and other popular satellites to give you hands on experience in image processing techniques. First we will go over the basic tools in ENVI and learn how to navigate the software. Then we will dive into and learn step by step the fundamental techniques in satellite remote sensing image processing such as:
image mosaicing
radiometric calibration
multiple atmospheric correction techniques (Fast Line of Sight Atmospheric Analysis of Hypercubes and Dark Object Subtraction)
supervised and unsupervised classification
vegetation indies
band ratios
and many more!
Additional satellite images and data will be provided so that you can practice these techniques on your own. I will also provide you with additional resources that you can download and use in your future remote sensing career! We will also go over on how to locate and download FREE remote sensing satellite images!
Once you have learned the basics of ENVI we will go into intermediate and advanced ENVI remote sensing processes such as:
hyperspectral data analysis
image registration
anomaly detection
creating a burn index map
mineral mapping from hyperspectral images
spectral angle mapper
time series analysis
pansharpening and much more!
I hope that you ENROLL NOW and learn the remote sensing software that industry and research positions require! Start your remote sensing career here and learn the basics of remote sensing image analysis using ENVI software!