I have a 2 by 226200 table, conveniently read in by read.table(), which exhibits some strange behavior when plotted by plot(V1,V2). The general pattern for the range of windspeeds, [0<V1<50] is as expected -- the wind gust falls in the interval [V1<V2<65] except for certain values of V2. For V2 == c(15,26,37,48,59), the V2 values are positioned at one-tenth of the V1 (i.e., as if I had issued the command plot(0.1*V1,V2) for just those values of V2 -- see attached plot, test.png). The only other values of V2 in the range, 4 and 70, also seem to be affected but aren't well enough represented to show up clearly on the plot. However, if I plot(ws$V1[ws$V2==48],ws$V2[ws$V2==48]), I see the second attachment, test2.png, which confirms that the wind speed (V1) really should be positioned where one would expect. I haven't seen any messages covering this behaviour and so am looking for an explanation. I'm running:> R.Version()$platform [1] "i686-pc-linux-gnu" $arch [1] "i686" $os [1] "linux-gnu" $system [1] "i686, linux-gnu" $status [1] "" $major [1] "1" $minor [1] "8.1" $year [1] "2003" $month [1] "11" $day [1] "21" $language [1] "R" on Red Hat 9.0. TIA, Clint -- Clint Bowman INTERNET: clint at ecy.wa.gov Air Quality Modeler INTERNET: clint at math.utah.edu Department of Ecology VOICE: (360) 407-6815 PO Box 47600 FAX: (360) 407-7534 Olympia, WA 98504-7600 -------------- next part -------------- A non-text attachment was scrubbed... Name: test.png Type: image/png Size: 4164 bytes Desc: Url : https://stat.ethz.ch/pipermail/r-help/attachments/20040329/bb5d0b42/test.png -------------- next part -------------- A non-text attachment was scrubbed... Name: test2.png Type: image/png Size: 2231 bytes Desc: Url : https://stat.ethz.ch/pipermail/r-help/attachments/20040329/bb5d0b42/test2.png
On Mon, 29 Mar 2004 14:06:36 -0800 (PST), Clint Bowman <clint at ecy.wa.gov> wrote :>I have a 2 by 226200 table, conveniently read in by read.table(), which >exhibits some strange behavior when plotted by plot(V1,V2). The general >pattern for the range of windspeeds, [0<V1<50] is as expected -- the wind >gust falls in the interval [V1<V2<65] except for certain values of V2. >For V2 == c(15,26,37,48,59), the V2 values are positioned at one-tenth of >the V1 (i.e., as if I had issued the command plot(0.1*V1,V2) for just >those values of V2 -- see attached plot, test.png). The only other values >of V2 in the range, 4 and 70, also seem to be affected but aren't well >enough represented to show up clearly on the plot. > >However, if I plot(ws$V1[ws$V2==48],ws$V2[ws$V2==48]), I see the second >attachment, test2.png, which confirms that the wind speed (V1) really >should be positioned where one would expect. I haven't seen any messages >covering this behaviour and so am looking for an explanation.I can't quite see how it would generate the symptoms you saw, but a common source of oddities is that data is read as factors rather than as numeric values. You can see the difference using the str() function, e.g.> str(x)num [1:10] -0.4897 0.6804 0.6979 -0.1203 -0.0428 ...> str(as.factor(x))Factor w/ 10 levels "-1.65972758..",..: 4 7 8 5 6 9 2 10 3 1 I'd check your V1 and V2. Duncan Murdoch