points

Ordering of points in R lines plot

由 不想你离开。 提交于 2019-11-28 04:00:14
问题 I want to add a fitted line of a quadratic fit to a scatteprlot, but the ordering of the points is somehow messed up. attach(mtcars) plot(hp, mpg) fit <- lm(mpg ~ hp + I(hp^2)) summary(fit) res <- data.frame(cbind(mpg, fitted(fit), hp)) with(res, plot(hp, mpg)) with(res, lines(hp, V2)) This draws lines all over the place, as opposed to the smooh fit through the scatterplot. I'm sure this is pretty straightforward, but I'm a little stumped. 回答1: When you plot a line, all the points are

Calculating angle between two points - java

由 早过忘川 提交于 2019-11-27 16:39:00
问题 I need to calculate the angle in degrees between two points, with a fixed point that is connected with the given two points by a line. Here is an image that illustrates what I need: Here is what I have tried so far: public static float GetAngleOfLineBetweenTwoPoints(float x1, float x2, float y1, float y2) { float xDiff = x2 - x1; float yDiff = y2 - y1; return (float) (Math.atan2(yDiff, xDiff) * (180 / Math.PI)); } It's pointless to say that it doesn't provide the correct answer. 回答1: You can

Closest point to a given point

由 只谈情不闲聊 提交于 2019-11-27 07:06:31
I have a set K of randomly selected pixels in a 2D image. For every other pixel in the image I need to find out which pixel in set K is closest to it (using the standard sqrt(dx^2 + dy^2) measure of distance). I am aware that there may be more than one solution for each pixel. Obviously it can be done by brute force against every pixel in the set, but I'd rather avoid this as it's not efficient. Any other good suggestions? Cheers. Don't forget that you don't need to bother with the square root. If you just want to find the nearest one (and not it's actual distance) just use dx^2 + dy^2 , which

Pixels vs. Points in HTML/CSS

由 百般思念 提交于 2019-11-27 00:35:44
When creating an HTML page, should I specify things like margin s with pixels or with points in CSS? Is one of them considered to be better practice than the other? Any advantages or disadvantages to either one? Use px or em CSS FONT-SIZE: EM VS. PX VS. PT VS. PERCENT Points (pt): Points are traditionally used in print media (anything that is to be printed on paper, etc.). One point is equal to 1/72 of an inch. Points are much like pixels, in that they are fixed-size units and cannot scale in size. Generally, 1em = 12pt = 16px = 100%. [Conclusion] The winner: percent (%). JohnB note: this is

Pixels vs. Points in HTML/CSS

由 ╄→尐↘猪︶ㄣ 提交于 2019-11-26 09:24:42
问题 When creating an HTML page, should I specify things like margin s with pixels or with points in CSS? Is one of them considered to be better practice than the other? Any advantages or disadvantages to either one? 回答1: Use px or em CSS FONT-SIZE: EM VS. PX VS. PT VS. PERCENT Points (pt): Points are traditionally used in print media (anything that is to be printed on paper, etc.). One point is equal to 1/72 of an inch. Points are much like pixels, in that they are fixed-size units and cannot
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