An Introduction to the AppEEARS Point Sampler.
Presented by the Land Processes Distributed Active Archive Center or LP DAAC.
The Application for Extracting and Exploring Analysis Ready Samples or AppEEARS provides a quick and
easy way to access and transform geospatial data from several federal archives.
It allows for spatial, temporal, and band and layer subsetting, and provides interactive data visualizations
for each sample output.
Using the AppEEARS Point Sampler users can submit geographic coordinates for their specific points of interest.
AppEEARS will return the desired data requested alongside associated quality data as csv files.
Users can also explore and compare data values and associated quality data using the AppEEARS visualization tabs.
This video provides a brief overview of how to submit a Point Sample request, visualize
the output, and download the data.
First, find the AppEEARS landing page using this URL.
A NASA Earthdata Login account is required to use AppEEARS.
Login with your NASA Earthdata account by clicking on the sign in button.
Don’t worry if you do not have an account, they are freely available and easy
to set up.
Just click the sign in button on the AppEEARS page and then register for an
account on the Earthdata login page.
Let’s explore the AppEEARS Point Sampler.
In this example we are going to look at MODIS Land Surface Temperature and Vegetation
data at flux towers locations in Australia from January 1, 2015 to December 31, 2017.
First, click Extract then Point Sample.
There are three ways to start a request.
You can either start new request, copy a previous request, or upload a JSON file
with request parameters.
This JSON file is provided with the output files of each request.
We are going to submit an AppEEARS Point request by clicking Start a new request
and filling out the request form from scratch.
This is the Point request form.
First, we will name the request.
Let’s name this request Australian Flux Towers.
When extracting by Point you can either upload a CSV file containing your coordinates along
with an optional point ID and category, manually entering the coordinates and optional information into
the box to your right, or adding points to the map in the viewport by
using the point icon and clicking on the map.
Once the box is populated with point locations they will display on the map.
Let’s start by uploading a CSV file of the Flux Tower locations in Australia based
on data from the Terrestrial Ecosystem Research Network or TERN and the University of Queensland.
Drag and drop the file into the box.
You can now see all of the flux tower points that were in the CSV file.
You will notice that there are four items for each location.
The first two items are the optional ID and category.
Inclusion of these two items allows for further investigation into the output data.
The second two items are the required latitude and longitude.
AppEEARS allows you to subset temporally, meaning you can select the dates or reoccurring date
range that you are specifically interested in.
I’m going to select January 1st, 2015 to December 31st, 2017.
You can also subset the data products by adding only the data layers or variables you want.
If you want to learn more about a layer you can click on the I
icon next to it.
If you accidentally added a layer you can remove it by clicking on it under selected layers.
Here you can select multiple layers from different data products.
Now Im going to search for the rest of the data I want and add
the layers I need.
When you are satisfied with the layers you’ve selected, submit your request.
You will receive an email to confirm that the request has been successfully received and
a second email when the request is complete.
To see your request, click the Explore tab or click the link in the second email.
The Explore tab contains all of the requests you've submitted and their details, status, and
links to visualize and download the sample output.
Note that upon the completion of your request you will have 30 days to view
and download your request.
After 30 days, your request status will change to expired and you will need to
reprocess it to view and download the request again.
Once you are ready to explore the data, find your request and click on the
graph icon to view the contents of this request.
AppEEARS allows you the preview and interact with your data values.
These graphs show the data values for each point location through time.
For point samples, AppEEARS provides three ways to explore and compare the data, temporally, by
layer, and categorically.
With all of these options you can filter the data to show either all of
the data or only data identified as good quality data based on the MODLAND QA bits.
Using the temporal comparison feature, you can examine data values through time via a time
series graph or also compare the data annually through the stacked time series graph.
Observe the data values with associated quality information in the table below.
Using the layer comparison option, you can compare data values between two layers over time
via a time series line graph and a scatter plot.
Finally, using the categorical overview tab you can examine the quality information and aggregated data
values via box and whiskers plots.
Since the input points contained the optional ID and category fields we can leverage them
to gain additional insights into the data.
On this page, you can filter the data down by clicking on one of the
box and whiskers.
For example, if you only want to look at good quality grassland data you can
click on the box and whisker labeled 0 and on the category identified as grasslands.
This will show you the sites identified as grassland and will filter the box and
whiskers to only show good quality data.
The statistics contained in the boxplots are calculated from the aggregation of all data values
for the time period requested for a given grouping.
You can hover over the box and whiskers to see the data values.
Once you are done exploring the data you can download the output files via the
dropdown arrow or by returning to the explore tab.
In addition to the data extracted for your requests, AppEEARS offers a number of supporting
or auxiliary files including ISO compliant metadata, a granule list with links to the source
data files, a readme for additional request details, and a JSON file containing your request
parameters to share and reproduce requests.
Finally, the CSV files containing the extracted data values are available to download individually or
as a bulk download.
You can also download all supporting files and data files as a zip file.
So there you have it, AppEEARS, an intuitive time-saving application that provides access to geospatial
data from a variety of federal data archives all in one place.
If at any time you need assistance while using AppEEARS, feel free to click Help.
This will provide you with information on how to use AppEEARS, what data products are
available in AppEEARS, and how to contact the LP DAAC.
You can also always contact the LP DAAC User Services team at lpdaac@usgs.gov.
Thank you for watching this video on the AppEEARS Point Sampler presented by the Land
Processes Distributed Active Archive Center or LP DAAC.