Εμφάνιση αναρτήσεων με ετικέτα Free download. Εμφάνιση όλων των αναρτήσεων
Εμφάνιση αναρτήσεων με ετικέτα Free download. Εμφάνιση όλων των αναρτήσεων

Κυριακή 20 Δεκεμβρίου 2015

How to Download Sentinel Satellite Data for Free



Download Sentinel-1 and Sentinel-2 Satellite Data
If you want to download Sentinel satellite data, then you’ve come to the right place.


One of the most exciting developments in remote sensing at this time is the European Space Agency’s Copernicus Programme.

Copernicus’ six Sentinel satellites collects comprehensive pictures of our land, ocean, emergency response, atmosphere, security and climate change to understand the health of our planet.

Until very recently, this data has become available to the public at no cost

Today, we show you step-by-step how to download Sentinel satellite data:



Sentinels Scientific Data Hub



In 2014-15, Sentinel-1 and Sentinel-2A were successfully launched from Europe’s Spaceport in French Guiana.

One Sentinel scene after the other, data has been rolling out on a user interface called the Sentinels Scientific Data Hub.

It’s now available for the public to access.

But you will have to hop through a couple of hoops before you can get your fingers on it.

Follow these steps to download free Sentinel satellite data:


Step 1: Create a User Account
Go to Sentinels Scientific Data Hub.

In the top-right of the webmap, click the SIGN UP button.

Insert valid entries for your name, email and location. Click register. Validate your email.

With a few clicks of the mouse, you’ve gain access to ESA’s Sentinel data.

Sign Up Sentinel

Step 2: Select Your Area of Interest
Where is your study area?

Using the SEARCH CRITERIA text box in the top-left, type in your area of interest.

In our example, we’ve typed Germany. Click Enter twice.

From here your search will yield results for all the Sentinel satellite data available.

Sentinel-1 (Synthetic Aperture Radar C-Band) swaths are depicted in red. Sentinel-2 (multispectral data) swaths are depicted in green.

Read More: What’s the difference between active and passive sensors?

Search Criteria Sentinel

Step 3: Download Sentinel Data
Now, that we have our user account created with our study area defined – all we have to do is sift through the results and download our chosen Sentinel data.

As we are working with large data sets, you will have to be patient with download speeds. It’s easy for the server to timeout during the download.

Select the product you want to download. S1A is Sentinel-1A. S2A is Sentinel-2A.

Below the product thumbnail that has the download URL. This is what you want to clip in order to download your chosen Sentinel data.



What’s Next?
After you download Sentinel satellite data, chances are that you are going to want to display it in the visible spectrum. This is exactly how our eyes see objects around us.

Each image is separated by their respective spectral band. See our table below for the spectral bands of Sentinel 2. Sentinel 2B will be identical to Sentinel 2A.

If you want to combine the red, green and blue channels as composite bands (such as Google Earth imagery) – read our composite bands tutorial.

…Or maybe you’d like to perform an NDVI analysis in ArcGIS or an image classification.

You now have free satellite data from Sentinel to help you.


What are the Spectral Bands of Sentinel 2A and 2B?
We’ve listed below, the spectral and spatial resolution of Sentinel 2A. There are 13 bands in total. Four spectral bands have a 10 meter resolution. Six bands have a 20 meter resolution. And the remaining 3 have a spatial resolution of 60 meters.

Here are the spectral band details for Sentinel 2A:




Source: SENTINEL-2 Spatial Resolution

Each single satellite revisit time is 10 days. Because there are two satellites (Sentinel 2A and 2B), this means it has a combined constellation revisit of 5 days.

Source: GIS Geography

Τετάρτη 18 Νοεμβρίου 2015

Free GIS Software: Map the World With Open Source GIS Mapping Software

Τετάρτη 30 Σεπτεμβρίου 2015

Free Download of Solar Radiation Maps: Global Horizontal Irradiation (GHI)



The maps of Global horizontal irradiation for various countries and regions are available on this page to download. SolarGIS database is the source of solar data represented on the maps.

Global horizontal irradiation is the most important parameter for evaluation of solar energy potential of a particular region and the most basic value for PV simulations.
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The maps are free for public use, their reproduction and adaptation is authorised provided the following source is acknowledged:

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By downloading a free map, you acknowledge that GeoModel Solar retains all rights, titles, and interest in the information provided by the maps, including the copyright, SolarGIS logo and all other intellectual property rights, and that GeoModel Solar has the right to make these maps available under Creative Commons Attribution-ShareAlike 3.0 Unported License.

GeoModel Solar makes no representations or warranties about the accuracy, reliability, completeness or suitability for any particular purpose of the free maps. You agree that GeoModel Solar is under no liability for any loss or damage (including consequential damage) that you may suffer from the use of the free maps.

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To get access to the maps, please follow the link here.