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Categories » BEAM Extensions » SMOS Box Use and Features
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SMOS Box Use and Features
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SMOS Box Use and Features
colour manipulation snapshot image pentium pc scatterplot speed improvement data values slider spinner subset statistics
8/31/09 4:51 PM
I am learning how to use SMOS-Box 1.01 on Beam 4.6 under XP Pro on a pentium PC (2.0 GHz Xeon, with 2.00GB of RAM, and 100Gbyte spare on each disk).

So far, I have come across the folowing issues:

1) Some apparently simple functions eg. Statistics, HIstogram, Scatter Plot seem to take an excessive amount of time (often 10 to 20 mins.). Is this normal, and if so, can any speed improvement be realized (recognizing the large size of the SMOS products)? If not, can anyone suggest a way to speed up operations? One possible way would be to subset the product to a region of interest before the Stats are computed. Can that be done?

2) Using the snapshort information tool, with Synchronise, Snapshot and Follow all checked, at one time I found there was a white selection box over the snapshot image which I used to select a new location (snapshot) along the track for the snapshot (hexagonal) image. Then for some reason the box stopped appearing! The slider and spinner continued to work, for selecting different ID's (snapshot numbers) and plotting of the actual snapshot image continued, but I could no longer select a new location, as the selection box went away. [Further tesing shows clicking on the slider tool can bring back the whitle selection box, but moving it about the map seems to be problematic]

3) When I select 'View->Tool Windows->Colour Manipulation' and a colour legend is displayed, I am having difficulty getting a nice color scale (other than white or gray) for Stokes 1 and 2 in the L1C products eg. OPER_MIR_SCLD1C_20121117T025058_20121117T034006_204_001_1.dbl.

The data range for these bands is huge, and mostly negative, as seen in a scatterplot for eg. of Stokes_1 v's Stokes_2. (0 to -2,500,000! Yet for the scenes over the ocean, the values fall inside a reasonable range (say -20 - 250). I cannot find a slider combination in the color tool that shows anything but grey or white in the image. It is as though there are very few data values, or peraps too few histogram bins (about 3-4) to give numerical detail over this big range.

and finally,

3) Are there plans to include additional SMOS products eg. ECMWF? It seems SMOS Data Viewer can read a much wider range of products, especially for ancillary data.

Any suggestions for workarounds would be appreciated.
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RE: SMOS Box Use and Features
9/1/09 1:37 PM as a reply to Derek M Burrage.
Hi Derek,

1) The statistical computation is dependent on the mode (browse or snapshot) of the view. The time you've mentioned is normal.
When set to snapshot the computation is much faster.
For statical computation it might be reasonable to create a subset. But the SMOS specific tools wont work anymore.
To create a subset click on in the tool bar and define the subset. See also: Subset Dialog.
You can also zoom to the area of interest in the view. And select from the context menu Create Subset from View....
Real subsets with full functionality will be supported in a later version, also better performance will be provided.

2) The location indicator in the view is only visible as long the slider is dragged. After releasing the slider the white rectangle disappears.
That it completely disappears, we have not noticed yet. Can you describe in more detail what you have done before it disappeared. So that we can reproduce the error and fix it.

3) You can import a wide range of predefined colour palettes, by clicking on the icon. You can use the icon to adjust the slider range to 95% of the values, to better adjust the sliders. Also it might be helpful to click on the ''Rough statistics" indicator to get the exact histogram.
But unfortunately it is not possible to adjust the bin size or the upper and lower bound of the histogram.

4) Yes, we will support more products in later versions.


best regards
Marco
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