Re: Get Graphics Coordinates accuracy
- To: mathgroup at smc.vnet.net
- Subject: [mg92348] Re: Get Graphics Coordinates accuracy
- From: m.r at inbox.ru
- Date: Sun, 28 Sep 2008 07:21:54 -0400 (EDT)
- References: <gbjm5i$383$1@smc.vnet.net>
John Jowett wrote: > I came across a limitation in the mechanism for copying coordinates of > points in 2D graphics (the Get Coordinates button in the Drawing Tools > palette) in V6.03. > > Consider the following plot of a sine wave > > Plot[Sin[2 x], {x, 20270, 20275}] > > When I try to select and paste the coordinates of the two crests of > the wave, I typically get two points with the same x-coordinate > > {{2.027*^4, 0.99}, {2.027*^4, 0.99}} > > whereas I would expect the two x-coordinates to be around > 20270.3 and 20273.5, values which are well separated on the plot. > > This seems to happen because the Get Coordinates function only returns > the first 4 digits of the coordinates. > > Does anyone know of a way to fix this ? Obviously, in this > demonstration example, I could change variables to x1=x-20270 but in > the more complicated problem I am working on, this is not so easy. > > John Jowett As a workaround, you can do Plot[Sin[2 x], {x, 20270, 20275}, CoordinatesToolOptions -> {"DisplayFunction" -> (#&), "CopiedValueFunction" -> (SetPrecision[#, $MachinePrecision]&)}] and then you can apply N to the copy-paste result to convert it back to MachinePrecision. Maxim Rytin m.r at inbox.ru