ellipse

问题 Ellipse general equation: a * x ^ 2 + b * y ^ 2 + c * x * y + d * x + e * y + f = 0 回答1: We can start from the parametric equation of an ellipse (the following one is from wikipedia), we need 5 parameters: the center (xc, yc) or (h,k) in another notation, axis lengths a, b and the angle between x axis and the major axis phi or tau in another notation. xc <- 1 # center x_c or h yc <- 2 # y_c or k a <- 5 # major axis length b <- 2 # minor axis length phi <- pi/3 # angle of major axis with x

问题 I'm working on a program which is displaying cgm graphics. For an elliptical arc, I get vectors to the start and end angles so after I calculate the angles and try to use them in an arc, I am getting the wrong angles drawn. In the image below : The gold lines show the vectors I get. The red arc is the ellipse I get trying to draw the image with the angles given. The green arc which I get is the image with the ellipse changed to a perfect circle. Is there a way I can correct this? Brief exapme

问题 I'm trying to make a function in Lua or VB based code to draw / plot a filled ellipse. I don't have much knowledge about this math and I can use some help. I Googled everything there is to Google about drawing ellipses with code but I can't find a good simple working example in VB or Lua for a filled one. On a previous post on this site I did get an answer about how to draw a normal ellipse but nothing came up for a filled one, that's why i make a new topic for a filled one. Here are a few

问题 OpenLayers supports tissot's ellipses natively by adding a sphere to the circular() method. Unfortunately the Leaflet L.circle() does not support such feature. How do I draw tissot's ellipses with Leaflet? 回答1: EDIT 3: New proposition using leaflet-geodesy which seems a perfect fit for your need. It is exempt from Turf's bug (see Edit 2 below). The API is quite simple: LGeo.circle([51.441767, 5.470247], 500000).addTo(map); (center position in [latitude, longitude] degrees, radius in meters)

问题 I need help adding an ellipsis to my pagination script. I can't find anything simple on Google. So that's why I ask on here. Thank you!!! Here is the code; if (isset($_GET['p'])) { $pageno = $_GET['p']; } else { $pageno = 1; } // if $query = mysql_query("SELECT count(id) FROM m3_musicblog"); $query_data = mysql_fetch_row($query); $numrows = $query_data[0]; $rows_per_page = 4; $lastpage = ceil($numrows/$rows_per_page); $pageno = (int)$pageno; if ($pageno > $lastpage) { $pageno = $lastpage; } /

问题 So I tested this code (intersection between two ellipses, look at the accepted answer), but if I change one of the ellipses to a line geometry (or path geometry representing a line) and it gives me no intersection. Does any one know why? Does combine geometry work on area of the geometry, and since lines have no area, it gives no intersection? Since eventually I would want to see if the arbitrary path geometries intersect. I guess I would have to find a way to "pad" the path with some area,

问题 I regularly have upwards of 10^8 sets of ellipse fitting data to solve coming out of monte-carlo simulations by looping through the Halir & Flusser (Page 4, Figure 2) ellipse fitting algorithm. Is there a way of vectorizing the process/algorithm/function, so that I can send the lot at once to the function and it returns 10^8 solutions to the 10^8 sets? I want to stick with Halir & Flusser as it is very robust. Having used other ellipse-fitting methods, this one always returns ellipses I can

问题 Given data points in the xy plane, I would like to use scipy.optimize.leastsq to find fit parameters for an ellipse (which cannot be written as a function of x and y). I tried setting the entire equation equal to zero, and then fitting this function, but the fit is failing to converge with error output "The relative error between two consecutive iterates is at most 0.000000." The code is shown below, as well as the output. The fitter clearly does not find any reasonable parameters. My

问题 I need to create an ellipse like below with custom colors. I'm using Intervention image library to achieve this. What i've done is : I've created 6 different transparent images for each section. And trying to create a canvas and then masking other layer on it but the result is not as expected. I'm able to color only the first section of the image through this process. Image::configure(array('driver' => 'gd')); $img = Image::canvas(150,104,'#000')->insert(WWW_ROOT.DS.IMAGES_URL.'test/masks/1

问题 Could you please help me with the following question: I want to solve a second order equation with two unknowns and use the results to plot an ellipse. Here is my function: fun = @(x) [x(1) x(2)]*V*[x(1) x(2)]'-c V is 2x2 symmetric matrix, c is a positive constant and there are two unknowns, x1 and x2 . If I solve the equation using fsolve, I notice that the solution is very sensitive to the initial values fsolve(fun, [1 1]) Is it possible to get the solution to this equation without