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wattsup
Joined: 16 Feb 2008 Posts: 3
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Posted: Mon Apr 07, 2008 1:47 am Post subject: Having trouble importing time series temperature data |
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Hi,
First let me say I'm overall satisfied with the program, it has been very useful to me in climate science research.
Second, I'm running into a snag due to the way Dplot handles import. I don't think it is a bug, but simply something not envisioned.
The data I use is historical monthly temperature records, which are in the format:
YYYY.mm temp temp temp
Where YYYY.mm would look like this:
1950.1
1950.2
1950.3
...
1950.12
1951.1
1951.2
...
etc
or this:
1950 1
1950 2
1950 3
...
1950 12
The problem is of course that Dplot can't handle using these values for the X axis. So I have to discard these and simply let Dplot handle the data as "months" by automatically figuring out the x axis from the data. This of course leaves me to plot years manually and to have to always set the tick interval on the x axis to 12 so that I can count years.
Unfortunately, I don't have control over the data format as it is provided by the National Weather Service and other agencies, and thus it presents a bit of a quandary as to what to do to handle this better. I run new plots 4-5 times a month, so any sort of solution would be welcome.
Here is sample data file for you to test with:
ftp://ftp.ssmi.com/msu/monthly_time_series/rss_monthly_msu_amsu_channel_tlt_anomalies_land_and_ocean_v03_1.txt |
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DPlotAdmin Site Admin
Joined: 24 Jun 2003 Posts: 2310 Location: Vicksburg, Mississippi
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Posted: Mon Apr 07, 2008 9:46 am Post subject: |
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Yuck
I started to reply that you could use Edit>Operate on X with the dates in the form Y.M. But that won't work because January would be indistinguishable from October. For the Y.M form it's hopeless; I'll need to write a plugin to handle those.
For the space-separated year and month you can still make this work, though it requires a bit of hoop-jumping. Open the file with "Pick columns to Plot" checked. Enter 0 for "Use column _ as X axis" and check the first curve (the year) in the "Use these columns for Y" list (all others should already be checked - leave them checked).
Now use Generate>Y=f(X,Y1,Y2,...) and enter Y=DATE(Y1,Y2,1) from (for this file) X=0 to 350 with an increment of 1.
Click the Erase button and delete the first two curves (year and month).
Select Generate>Switch Independent Variable and select the last curve (which should be labeled DATE(Y1,Y2,1)).
Right-click any of the numbers on the X axis and select "Calendar date".
Wasn't that fun?
DPlot doesn't interpret your column headings correctly, but those are fairly easily entered manually. I'll put all this on my to-do list for a plugin that removes all the tedium above, but I can't promise when that might be available. _________________ Visualize Your Data
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jsc
Joined: 02 Dec 2005 Posts: 222
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Posted: Mon Apr 07, 2008 10:05 pm Post subject: |
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A little work with excel to turn the first two columns into a date with the =date(year,month,day) formula, and then for column labels concatenate the first two rows, would get you a little further than totally manual manipulation. A bit of a macro in excel, or using a macro in a good text editor like UltraEdit would get you 99% there, though not as neatly as David writing a plugin, to be sure! |
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wattsup
Joined: 16 Feb 2008 Posts: 3
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Posted: Tue Apr 08, 2008 9:43 pm Post subject: Thanks |
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I'm VERY appreciative of the ideas. Perhaps by making the . separator selectable (I found one using /) but this could go on ad infinitum.
Now for the really ugly one, NASA GISS data:
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt
Any ideas on how to take this train wreck and make a plot of monthly data? |
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DPlotAdmin Site Admin
Joined: 24 Jun 2003 Posts: 2310 Location: Vicksburg, Mississippi
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Posted: Tue Apr 08, 2008 10:39 pm Post subject: |
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Quote: | Any ideas on how to take this train wreck and make a plot of monthly data? |
Please go away
Just kidding. No, there's no easy (or hard) way I can see to import that into DPlot and get it as it is intended. If I personally had an immediate need to plot that data I'd probably import the table into Excel and write a VBA routine to do the dirty work. Long term I'll at least think about creating a file import plugin to handle that arrangement. But please don't expect anything real soon, as my plate is currently overflowing. _________________ Visualize Your Data
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