Difference between revisions of "Downloading, Visualizing and Preprocessing Sentinel-2 Data in SNAP"

Revision as of 02:30, 23 December 2021

Introduction

Getting Started

Install Required Software

Why do we need to take these steps

explanation of why it is being done to the data and what is being done

Getting Sentinel-2 Data

There are three ways we will outline in this tutorial to access Sentinel-2 data, through two Copernicus data servers, Scihub and SNAP Product Library, and Google Earth Explorer.

Copernicus account

1. Navigate to the Copernicus open access hub through this link 2. click the person icon with a question mark located in the upper right hand corner of your screen. 3. In the lower left corner of the drop down, click Sign Up and fill out all the necessary fields of the corresponding forms, being sure to enter a valid email address. 4. once your account has been created and validated, sign in using the same dropdown in step 3.

We now have access to our Copernicus and therefore Sentinel data. For more help, this link provides a comprehensive overview of the steps necessary https://scihub.copernicus.eu/userguide/SelfRegistration

Scihub

File:Insert.png

Figure 1: Scihub Display page

In Figure 1 we see the default Scihub display. depending on the data we are looking for, we are able to filter our search by location, sensor, and in Sentinel-2's case, even satellite.

Below the login icon there are three Icons (figure 2)

File:Insert.png

Figure 2: Scihub Navigation Icons

the first or top one show the map layers. Click through the options and note the Sentinel-2 Cloudless + Overlay. the second and third icons are in a slider format. the upper icon allows for navigation around the globe. Use this to find your area of interest. Once found switch the slider to the lower icon. This setting allows you to select an area of interest (AOI) which is your first filter for Sentinel data.

Next, navigate to the three horizontal lines icon, found on upper left corner of figure 1. this opens the advanced search dropdown, which allows for the filtering of available data by metrics of sensing and ingestion period, mission and the associated characteristics of each. After filtering, click the search icon to search the repository for images that meet both your included location and advanced search criteria.

If any images match your criteria the advance search dropdown will be replaced with the results.

SNAP Product Library

Google Earth Explorer

Subsetting to AOI

Exploring Data in SNAP

Navigation Tab

Colour Manipulation Tab

RGB Exploration

RGB image profiles

Resampling to increase Usefulness

Image Classification Exploration

Spectrum View

Pin Manager

Sentinel-2 Toolbox

References

Geospatial Ecology and Remote Sensing. (2018a, March 13). Exploring Sentinel-2 multi-spectral band combinations in SNAP. https://www.youtube.com/watch?v=vtlN5MXYGaY

Geospatial Ecology and Remote Sensing. (2018b, March 13). Exploring spectral response curves from Sentinel-2 in SNAP. https://www.youtube.com/watch?v=E8Tu_IaJl6c&list=PLf6lu3bePWHCOUjTDZRNx5N07otDM8iUq&index=2

SNAP - Explore Sentinel-2 products (Old version). (2016, January 16). https://www.youtube.com/watch?v=tR_7Oq80TkA

@@ Line 8: / Line 8: @@
 == Getting Sentinel-2 Data ==
-There are three ways we will outline in this tutorial to access Sentinel-2 data, through Scihub, Google Earth Explorer and in the SNAP interface.
+There are three ways we will outline in this tutorial to access Sentinel-2 data, through two Copernicus data servers, Scihub and SNAP Product Library, and Google Earth Explorer.
+==== Copernicus account ====
+. Navigate to the Copernicus open access hub through this link
+. click the person icon with a question mark located in the upper right hand corner of your screen.
+. In the lower left corner of the drop down, click ''Sign Up'' and fill out all the necessary fields of the corresponding forms, being sure to enter a valid email address.
+. once your account has been created and validated, sign in using the same dropdown in step 3.
+We now have access to our Copernicus and therefore Sentinel data.
+For more help, this link provides a comprehensive overview of the steps necessary https://scihub.copernicus.eu/userguide/SelfRegistration
 === Scihub ===
+[[File:Insert.png|500px|thumb|right|Figure 1: Scihub Display page]]
+In Figure 1 we see the default Scihub display. depending on the data we are looking for, we are able to filter our search by location, sensor, and in Sentinel-2's case, even satellite.
+Below the login icon there are three Icons (figure 2) [[File:Insert.png|50px|thumb|right|Figure 2: Scihub Navigation Icons]]
+the first or top one show the map layers. Click through the options and note the ''Sentinel-2 Cloudless + Overlay''. the second and third icons are in a slider format. the upper icon allows for navigation around the globe. Use this to find your area of interest. Once found switch the slider to the lower icon. This setting allows you to select an area of interest (AOI) which is your first filter for Sentinel data.
+Next, navigate to the three horizontal lines icon, found on upper left corner of figure 1. this opens the advanced search dropdown, which allows for the filtering of available data by metrics of sensing and ingestion period,  mission and the associated characteristics of each. After filtering, click the search icon to search the repository for images that meet both your included location and advanced search criteria.
-=== Google Earth Explorer ===
+If any images match your criteria the advance search dropdown will be replaced with the results.
 === SNAP Product Library ===
+=== Google Earth Explorer ===
 -----
 == Subsetting to AOI ==