Sex ratio at LPS16

I did not have the chance to attend the latest ESA's Living Planet Symposium so I was curious to read Olivier's report. The picture in his post shows a crowded room... but what stroke me most is that it looks like 90% of the people in the room are middle-age men. There is no public data on the age or the sex of the participants to the LPS16. But there is a page on the LPS16 website listing all the authors.

A room at LPS16

A room at LPS16

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Les données SPOT5 (Take5) de niveau 2A ont été retraitées

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Le projet SPOT5 (Take5) vient de publier une nouvelle version des données SPOT5 (Take5) de niveau 2 pour corriger un petit nombre de petits défauts détectés lors du premier traitement :

     

  • sur deux sites désertiques, parmi les plus brillants de la planète, en Libye et Tunisie, l'un des seuils de détection des nuages était réglé trop bas, et de grandes parts du désert étaient donc classées comme nuageuses. Le seuil a été augmenté spécifiquement pour ces deux sites.
  • Les produits de niveau 2A sur les sites nordiques n'étaient pas produits lorsqu'ils étaient complètement couverts de neige. Le problème a été résolu, mais il n'est pas possible d'y estimer l'épaisseur optique des aérosols lors des périodes de couverture neigeuse. Ils sont donc traités avec une épaisseur optique par défaut.
  • les ombres de nuages partiellement masquées par de grands nuages n'étaient souvent pas détectées. La méthode de détection des ombres de nuages a donc été entièrement revue, ce qui a permis une forte amélioration des masques d'ombres.
  • Les images d'épaisseur optique des aérosols étaient un peu trop bruitées, nous avons donc augmenté la taille de la fenêtre de lissage spatial.
  • un site (BrailaCasasuRomania) n'avait pas été traité à cause d'un problème sur le modèle numérique de terrain en entrée (et nous n'avions pas vu le message d'erreur sur notre système prototype). C'est maintenant corrigé, toutes nos excuses aux utilisateurs de ce site.

 

Quelques unes des images acquises sur le site de Braila, Roumanie

  • un site (DevonUK) avait de piètres performances de superposition (de l'ordre du pixel) en raison d'un problème avec l'image de référence. Cette image a été changée et les niveaux 1C et 2A reproduits.
  • L'ancienne version a été supprimée du site de distribution des données et remplacée par la nouvelle. The données reraitées sont disponibles ici :

    https://spot-take5.org

     

    Pour éviter toute confusion entre les anciennes et nouvelles versions sur vos diques, la nouvelle version peut être reconnue en vérifiant le champ ci dessous dans le header xml.

    <DATE_PROD>2016-xx-xx</DATE_PROD>


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SPOT5 (Take5) reprocessed L2A data are online

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The SPOT5 (Take5) project just released a new version of all SPOT5 (Take5) L2A data to account for several small issues encountered during the first processing :

     

  • for two very bright desert sites (Libya, Tunisia), one cloud threshold was too low, and large parts of the desert were classified as clouds. The threshold has been changed specifically for these two sites.
  • the level 2A of Northern sites with a persistent snow cover were not issued in the first version. It has been solved, but as it is not possible to estimate aerosols above snow, they have been processed with a default Aerosol Optical Thickness value, as long as they are fully covered by snow.
  • the shadows below large clouds were often not detected. The shadow detection method has been completely reworked resulting in largely enhanced cloud shadow masks.
  • the Aerosol Optical Thickness images were a little too noisy, and the spatial smoothing of the values has been increased.
  • one site had been omitted because of a problem of DTM, which had been unnoticed (our processor is a prototype) :  BrailaCasasuRomania

Some extracts of the Level 2A products above the Romanian site of Braila.

  • one site (DevonUK) had a poor geometry because of a bad reference image. The reference image has been changed and the Level1C and level 2A have been reprocessed
  • The older version has been removed from the distribution site and replaced by the newer version. The reprocessed data are available here :

    https://spot-take5.org

     

    In order to avoid confusion between the older and newer version, you may check that the following HTML tag contains 2016 instead of 2015.

    <DATE_PROD>2016-xx-xx</DATE_PROD>


 

A python module for batch download of Sentinel data from ESA

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Note : the apihub is only accessible for those of you who submitted an account before the 21st of December. As a result, it is much easier to download the Sentinel- products at CNES PEPS facility. To access the data within PEPS, I have written a similar program to the one described below .

 

The Sentinel Scihub interface lets you search the catalog or download Sentinel data through a simple https request. For instance, to search all the S2 products within the catalog, just try the following URLs :

 

To select all the products which contain Toulouse :

  • you may login with your own Scihub account or with "guest", "guest"
  • All you need to know are your site  Lat, Lon (in this order) coordinates.

To select all the products which contain Toulouse ingested in the catalog after the first of December :

 

The Python routine, provided via the link at the end of this post, enables batch downloads of Sentinel-1 and Sentinel-2 (and probably soon Sentinel-3), from ESA distribution website. You know me, I have mostly tested it with Sentinel-2.

Sentinel_download runs on linux and it relies on the wget download utility. It might work on windows, probably with adaptations, but I do not know windows. If someone is willing to contribute, the software repository on github is open. That's what happened with the Landsat-download tool.

 

As the tool performs catalog searches, you can select the data by date, type, location, and even, for Sentinel-2, cloud percentage (if you trust ESA L1C cloud percentage). The readme file shows several examples, here, I'll only provide one :

 

python  Sentinel_download.py -s S2 --latmin 43 --latmax 46 --lonmin -1 --lonmax 2 -a apihub.txt -o 94 -m 25 -d 20151206

Here is the meaning of the options :

  • -s defines the satellite (S2, S2A, S2B, S1, S1, S1B)
  • --latmin 43 --latmax 46 --lonmin -1 --lonmax 2 define the bounding box in degrees (you can also only specify a point with --lat and --lon options)
  • - a apihub.txt provide the authentification to the website (guest guest still works)

  • -o is the path number (if you only want that one)

  • -m 25 is the maximum accepted cloud percentage to download (25%)

 

  • -d 20151206 is the start date of the period, and the download goes until now, unless you specify the final date (with -f option)

So, if you want to use this tool, get it from the github repository of sentinel-download.

 

SPOT (Take5) distribution server is open

 

 

ESA and CNES are glad to announce they just opened the new distribution site for SPOT4 (Take5) and SPOT5 (Take5) with a brand new look and feel compared to the previous SPOT4 (Take5) site. All the SPOT4 (Take5) data are available and may be downloaded, but the SPOT5 (Take5) site is almost empty (except for two sites : "France : Pornic" and "SouthAfrica : Mooreesburg"). The SPOT5 (Take5) part will hopefully start to be filled next week.

 

Here is the address :

 

https://spot-take5.org

 

To download data, you will need to register only once ("sign up" button), and then to log on ( "sign in"  button). Then you may either download each product or add it to the cart and use the cart to download batches of products. I'll try to better describe how it works in the next days, but meanwhile I am quite sure you will be able to manage on your own. There are only two things you need to know :

  • on the left part of the page (see the image below), there is a very convenient button to add all Level1A or all level 1C to the cart for a given site.
  • you will have to add the downthemall plugin to your firefox browser in order to download the cart. There are similar plugins for the other browsers, such as Metalink downloader for Chrome (which I did not test).

 

 

A new logo for SPOT (Take5)

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I had sometimes used the following home made logo for SPOT (Take5) experiments : the Paul Desmond standard is indeed based on a 5 beat rhythm, which is symbolized by the "5" on the time signature of the music score. The number 4 means that the beat corresponds to quarter notes. But the 4 and 5 can also remind of SPOT4 and SPOT5. However, the logo was very basic and not professional.

 

The communication services started from my logo to define the new official logo of the SPOT (Take5) experiments. Looking at it closely, you can see the music score, and it is much nicer and professional looking ! Thanks ESA !

Un nouveau logo pour Take5

Attention, ce post contient des termes techniques

 

J'avais utilisé parfois le logo suivant et tout à fait artisanal pour Take5 : le morceau Take5 de Paul Desmond est en effet un morceau sur un rythme à 5 temps, d'où le 5 sur l'armure. Le chiffrage de la mesure comporte également un dénominateur égal à 4 qui indique que la pulsation est à la noire.  Ce 5 et ce 4 permettaient donc d'évoquer à la fois le rythme à 5 temps, SPOT4 et SPOT5. Mais bon, tout ceci n'était pas très pro...

 

Les services de communication de l'ESA se sont un peu inspirés de ce logo pour définir ce qui devient le logo officiel de l'expérience Take5. En cherchant bien, on y reconnait la portée musicale. Et c'est clairement plus pro.

SPOT5 est sur l'orbite Take5/ SPOT5 is on Take5 orbit

 

Tout s'est très bien passé ce matin, et SPOT5 a atteint sa nouvelle orbite, 2,5 km plus bas. Félicitations et un grand merci à toute l'équipe des opérations du CNES ! Les premières images seront acquises la semaine prochaine. Ne quittez pas !

 

On m'a de nouveau demandé comment un petit changement d'altitude de 2 km pouvait produire un changement aussi important de cycle orbital (de 26 à 5 jours). C'est expliqué ici.

 

Everything went well this morning, and SPOT5 is now on its new orbit, 2.5 km lower. Congratulations and many thanks to CNES operations teams ! The first images will be acquired next week. Stay tuned !

 

I had that question again : why does an altitude change by only 2 kms result in an orbit cycle change from 26 days to 5 days ? It is explained here.