MAKING MORE USE OF GRID.TXT FILES -NEW FEATURE FOR DAWS?

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SteveHmeyer
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MAKING MORE USE OF GRID.TXT FILES -NEW FEATURE FOR DAWS?

Post by SteveHmeyer »

I have requested that Tim provide a way to better utilize grid.txt files. For those who are not that familiar with grid.txt page 133 0f the user manual for DAWS explains it.

In short it is a 30 x 30 grid of interpolated values of the observed data. Observations are irregularly spaced, to draw contours interpolated values are calculated at 900 regularlyspaced grid points. Contours are then drawn using the regularly spaced data making processing faster because calculations are simpler.

Each time you ask DAWS to analyze pressure, temperature etc. the file grid.txt is created.

The DAWS manual (p. 133) says the grid.txt file can be imported into spread sheets and used for further analysis. I do this with MS Excel and have students graph, for example the pressure change across a front. It is a very good teaching tool.

IT CAN BE TOOL FOR EACH OF US WHO USE DAWS AND CAN BECOME QUITE HANDY.

Often when we request a new feature for DAWS I am sure Tim experiences rapid breathing, has heart palpitations and gets that light-headed feeling just imagining the immense amount of coding, testing, compiling and fixing the request will require.

I do not think this request requires much of that, in fact this proposed feature addition should be quite easy and if implemented will be a handy tool.

FEATURE REQUEST:

1. A menu item to save the grid.txt file in a chosen location under a chosen name. Right now it has to be done manually.

2. An option to import files saved in grid.txt format and re-use them for an analysis. Unless the raw data was saved you could not plot that, and of course if you have the raw data you wouldn't use the saved grid.txt files. But there are many other uses for this.

Here is how I could use the proposed feature:

Example 1: Using archived data the 3hr pressure tendency is often missing. Perhaps a three hour interval is too long to see the advance of a fast moving front or low. You may perhaps want to see 12 hour pressure change. Temperature, dew point or any parameter that DAWS will analyze could be saved in grid.txt format and used in the future.

Example 2: Last night (Fri 7.30.2004) I was tracking developing warm sector thunderstorms that were trying to spin up into supercells. A small tornado touched down in Holton, IN (initial estimate is F3 based on video) destroying two homes damaging a dozen others and injuring two.

If the grid.txt feature was available I could have calculated hourly pressure, dew point and theta-e changes to have a better handle on the evolving situation.

Here is how it would work.

1. Export a grid.txt file, then a second.
2. Import each into an Excel workbook, each on its own sheet
3. Calculate a difference sheet in Excel
4. Export the difference sheet in grid.txt format to a file
5. Import the difference file into DAWS and use it for analysis.

If you think this would be a useful feature to add to DAWS1.2 please request it via the forum (third line down). Tim requests a short description so please keep the request brief.
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