[R] gridding values in a data frame
h.wickham at gmail.com
Fri May 1 00:15:55 CEST 2009
It's hard to check without a reproducible example, but the following
code should give you a 3d array of lat x long x time:
df$lat <- round_any(df$LATITUDE, 5)
df$long <- round_any(df$LONGITUDE, 5)
df$value <- df$TIME
cast(df, lat ~ long ~ time, mean)
On Thu, Apr 30, 2009 at 10:55 AM, dxc13 <dxc13 at health.state.ny.us> wrote:
> Hi all,
> I have a data frame that looks like such:
> LATITUDE LONGITUDE TEMPERATURE TIME
> 36.73 -176.43 58.32 1
> 50.95 90.00 74.39 1
> -30.42 5.45 23.26 1
> 15.81 -109.31 52.44 1
> -80.75 -144.95 66.19 2
> 90.00 100.55 37.50 2
> 65.41 -4.49 29.83 2
> and this goes on for a A LOT more records, until time=1200
> I want to create a 5 degree by 5 degree grid of this data, with the value of
> temperature in the appropriate grid cell. I want one grid for each time
> value. For each time value, this works out to be a 36x72 grid with 2592
> cells because the longitude spans -180 to 180 and latitude spans 90 to -90
> and they would be in increments of 5 degrees. If there are no temperatures
> available to be put into a grid cell, than that cell should get a missing
> value, NA, put into it.
> Also, could the gridded result for each time be written to a text file
> before processing the next time value?
> Hope this is clear.
> Thanks in advance.
> View this message in context: http://www.nabble.com/gridding-values-in-a-data-frame-tp23319190p23319190.html
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> and provide commented, minimal, self-contained, reproducible code.
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