November 3, 2014

POLDER On Line Help

POLDER On Line Help

General Overview

The aim of the POLDER Daily Browse is to give to users an overview of all POLDER acquisitions and to facilitate the ordering of POLDER products: it enables the selection of cloud-free dates and areas.

Image Characteristics

The large size image is called the "Daily Browse" and it has the same characteristics than the browse product: it corresponds to a 648 line, 1296 column image and it is subsampled (1:5) from the Level 1 product (30 Kilometers resolution). To limit transfer time trough the network, it has been compressed with a 25% rate in JPEG format and is around 100 kbyte.
The small size image is easier to load and display; it is a subsampling of the previous one (around 60 Kilometers resolution and 32 Kbytes image size)

Image Display Functions

Choice of datesBy default, the last available daily browse of the month is displayed. In order to select another date, you have to use the calendar or "previous date" and "next date" buttons.
If you come directly from POLDER daily browse or if you come from level1 ordering using daily browse, only dates for which available level 1 products exist are displayed.
If you come from level2 ordering using daily browse, only dates for which all level 2 products you have selected exist are displayed. The number of available products is reduced because we are in the scientific validation phase.
Image sizeThe image size button enables to modify the daily browse image resolution
Central Meridian (Image rotation)for a better display of your area of interest, you can choose the central meridian in the POLDER grid. For example: value +135 displays Japan in the middle of the image, value -100 displays the American continent. The rotation is kept if you change date or image size.
Selecting a pointdisplays the geographic coordinates of the last mouse click in the image.
For -20<latitudes<+20, the ADEOS cycle, orbit number and approximate overflight UT time are added.
The image rotation is taken into account.
Plotting of an areadisplays the geographic coordinates of the area selected in the image. The image rotation is taken into account.
The area is kept if you change date or image size.
Note that only an extraction by latitude is performed, no longitude selection is made for the extraction process. Use the "ZONE software" for longitude selection.
POLDER product selectionThis possibility is offered when you come from the ordering menu, if you have decided to order level 1 or 2 POLDER products using the Daily Browse visualisation. You first have to select an area and dates you want to order. Default areas are [-180,+180] longitude, [-90,+90] latitude. Default date is current date.
Each time you use the "add to order" button, your selection criteria will be displayed in the second window called "Order Elaboration". This window contains your identification. It also enables you to select the type of "media" you need and add a comment to your order. When your selection is finished, click the "Prepare order" button to display the final Order that will be sent by E-mail to the POLDER Ground Segment.

Memory constraints

At least 32 Mbyte of RAM are necessary in order to use the POLDER Daily Browse.
If you load several images, you will rapidly saturate the memory at your diposal. Use the "Network preferences" option of your browser menu to clear Memory and Disk cache.