Choosing a Data Access Tool: The Application for Extracting
and Exploring Analysis Ready Samples or AρρEEARS Area
Sampler. Presented by the LP DAAC.
NASA’s Land Processes Distributed Active Archive Center,
or LP DAAC is one of twelve NASA Earth Observing System
Data and Information System EOSDIS DAACs. It is located
at the USGS EROS center in Sioux Falls, South Dakota.
The LP DAAC ingests, archives, and processes NASA earth
science land processes data and information. It also
distributes the data through a variety of data access tools
that can help you find the data you need.
This video will be focusing on the new functionality in
AρρEEARS for extracting Area Samples.
The LP DAAC has deployed OPeNDAP services to allow
access to this data. OPeNDAP services enable you
to pull pixel values via HTTP requests.
Middleware services have been developed to interact with
OPeNDAP services. The AρρEEARS web application provides
access to these services. Leveraging these web services,
AρρEEARS provides access to analysis-ready data from a
variety of NASA datasets, allowing users to subset
spatially, temporally, and by band or layer.
During this video we will be answering these questions
based on using the data access tool: AρρEEARS
Area Sampler.
What type of data are you looking for? What is your
area size and how much data do you need? Do you need to
see your data before you download it? Do you need
to reformat, reproject, or subset your data? When do
you need your data and how do you want it delivered?
What type of data are you looking for? Available datasets
include Aqua, Terra, and Combined MODIS land products,
GPW UN-Adjusted population, SRTM Digital Elevation Model,
and WELD data products. All of our data products include
quality data that are included in your request output.
Terra and Aqua MODIS snow cover data and the GPW data
are provided in collaboration with the National Snow and
Ice Data Center and the Socioeconomic Data and
Applications Center. New products are continuously
being added to AppEEARS as well. From the “Help” tab
you can view the most up-to-date list of products
currently available in AppEEARS. Click on the product
name links for more information on a specific product.
What is your area size and how much data do you need?
With the AρρEEARS Area Sample function, you can retrieve
time series data for areas anywhere on the globe for a
defined set of layers. Do you need to see your data
before you download it? You can explore the summary
statistics from your region of interest within the
AρρEEARS application before you download the data.
You can also download the summary statistics, which
are provided by region of interest, dataset, and
observation. You can also view quality information
associated with your data. Do you need to reformat,
reproject, or subset your data? You can define your
region of interest by uploading a shapefile or geojson file
into the AppEEARS Extract Area Sample page, or use the map on
the right to draw a polygon or bounding box for your desired
study area. You can subset your time
period of interest by defining the Start and End Dates for
your request. To subset by band, search for
your product of interest and select it. From there, you
will see a list of available bands that you can select for
your request. Also, AρρEEARS Area Sampler provides you
with a list of output options for your sample request.
You can request the output files to be in GeoTIFF or
NetCDF-4 format for your requested products in either
their native projection, or reproject to a list of
coordinate reference systems allowed. All
transformations use nearest neighbor resampling.
If your region of interest spans multiple tiles for
a requested product, AppEEARS will mosaic the
tiles in order to generate your results. The list of
projections includes all projections native to
datasets available in AppEEARS.
When do you need your data and how do you want
it delivered? Your request will be processed after
you have named and submitted your sample request.
You will receive an email notifying you of a successful
submission. The time for AρρEEARS to process your
request depends on the amount of data you have
requested. You will receive an additional email once
your request is completed. Options to visualize and
download your results will appear in the AρρEEARS
“Explore” page once your request has been completed.
Once you have selected to download your data, AρρEEARS
will redirect you to the Download Area Sample Page.
All data output files can be found in the table of
files below. AppEEARS also provides the quality layers
associated with your requested datasets for you
to download as well. The supporting files
provided include a granule list, CSV files with quality
information and summary statistics, and metadata XML
files for the results of each of the specific products
you have chosen, a readme text file, and a JSON file
to share the request parameters with your
colleagues. On the download page, you can choose to
download a single file or bulk download all of your
results. Here is an example of an
AppEEARS output and the associated quality layer.
Thank you for watching our videos. If you are interested
in AppEEARS for Point Extraction, be sure to check
out our ‘Choosing a Data Access Tool: AppEEARS’ video.
Please visit the LP DAAC website at lpdaac.usgs.gov
for more information about AppEEARS and our other
data access tools.