NEO Analysis in 10 Easy Steps

Would you like to explore satellite data yourself? The new NEO analysis tool provides an easy way to compare imagery online and this new blog series highlights different Earth science concepts by pairing an introductory video with an investigation of relevant satellite imagery found here. After you’ve learned the steps, you can try these examples for yourself:

ANALYSIS: PACIFIC LIFE – HOW IS IT RELATED TO OCEAN TEMPERATURE?

ANALYSIS: HOT IN THE CITY

ANALYSIS: REFLECTIONS ON THE BLUE PLANET

Here are the basic steps to follow. Try it now!

Step one: Find a variable of interest

Search data sets either by selecting the category on the pull-down bar at the top or by expanding BROWSE DATASETS BY CATEGORY below.

Datasets are organized by main characteristics and are sometimes included in more than one category. For example, land albedo is under Energy and Land.

Some datasets are collected by multiple satellite sensors. For example, True Color (MODIS) and True Color (VIIRS).


Step two: Select data set at desired resolution and time

In this example, I select monthly Aerosol Optical Thickness (AOT) for February, 2017.

Under ‘View by date’: 1 mo sets the resolution to monthly.

Scroll to 2017 under ‘Select Year’.

Slide the horizontal timeline bar left or right to find the month of interest. If it’s blue, then it exists in the dataset and you can click it to see it in the display.

 


Step three: ADD TO ANALYSIS up to three images

Select ADD TO ANALYSIS in the top right corner. You will see the number of images change in the right, blue side of the top bar.

Repeat Steps 1-3 for up to two more images.

Once the top bar indicates ‘3 IMAGES’, you have reached the maximum and will not be able to add any more images to analyze unless you remove something.


Step four: View the list of selected images (optional)

Select IMAGES and a pull down list appears. To change your selection, ‘remove’ undesired images and repeat steps 1-3.


Step five: ANALYZE selected images

After you have selected up to three images you would like to explore, select ANALYZE on the top bar.


Step six: Select region of interest and LAUNCH ANALYSIS


Select an area to analyze by clicking and dragging a region on the map or by entering the latitude/longitude boundaries in the ‘Select Area’ tool. Then click on LAUNCH ANALYSIS at the bottom.


Step seven: View images for the region of interest 

Colored labels (top left) correspond to the color-coded thumbnails. The highlighted thumbnail is mirrored in the main display. Use the ‘Step’ button to see other images in the main display.


Step eight: Data Probe

Select ‘Data Probe’ and move the cursor around the main display. The pop-up box shows the values under the cursor, color-coded by the list, and the latitude & longitude. Here, red represents February, 2017; green is January, 2017; blue is December, 2016.


Step nine: Plot transect

Select ‘Plot transect’ and click and drag the cursor to draw a transect line. Values are plotted in a pop-up window as Distance vs variable, color-coded as before. The start of the line corresponds to the left side of the plot (0 Distance), shown here with the arrow. (You can move the pop-up window around if necessary.) If you want to measure the length of a feature, select ‘Distance’ and click and drag the cursor as before.


Step ten: Histogram

To compare the distribution of values in an area, select ‘Outline region’ to control the shape or ‘Select region’ for a box. Click and drag to draw the desired region. Select ‘Histogram’ and a pop-up window displays the distribution of values for the three images with the variable values on the horizontal line and the number of bins on the vertical line. In this example, February, 2017 had more than 1000 bins in this area reaching the maximum value (AOT equal to or greater than 1.0), while January only had a few and December had none at the maximum value. Again, the pop-up display can be moved.

Not demonstrated here, but one last analysis option enables you to make a scatter plot of the values in an outlined region or box. The two images plotted would be from the highlighted thumbnail and the next one (here it would be February and January). You can use ‘Step’ to change the pair plotted. The scatter plot tool is useful to explore relationships between two different variables. It is not as useful when all of the images are from one data set.

Here are a few examples to try for yourself:

ANALYSIS: PACIFIC LIFE – HOW IS IT RELATED TO OCEAN TEMPERATURE?

ANALYSIS: HOT IN THE CITY

ANALYSIS: REFLECTIONS ON THE BLUE PLANET

Tags:

Leave a Reply

Keep comments relevant. Inappropriate or offensive comments may be edited and/or deleted. Avoid adding Web site urls.

Contact Us

Need to get a hold of someone at NEO? Just fill out the form below.





Trouble with this form? Submit your comment here.