point

问题 I am trying to create a simulation of positions of 4673 of the nearest galaxies. The galaxies are points. I want to color a point on mouseover and load the name of the galaxy. I have spent many days trying to achieve it. I am able to change color, as well as do basic raycasting, however, I am unable to separately raycast/color individual point. All the points are raycasted and colored as a group as seen in the current version. What should I do to correct this? Thank you so much for your time

问题 What is the usual way to do math, addition, subtraction, on PCL (Point Cloud Library) data types, i.e. PointXYZ? There don't seem to be operators defined even for the basics. I thought maybe the PCL way was to convert to Eigen vectors, but there doesn't seem to be a constructor for that either. 回答1: For anyone who wants to do basic math with PointXYZ , here a quick example: pcl::PointXYZ a(0, 1, 2), b(10, 20, 30), c; c.getArray3fMap() = a.getArray3fMap() + b.getArray3fMap(); std::cout << "c="

问题 I am trying to split a large line shape by pairs of points along the line. Based on previous questions asked mainly by @mbcaradima here, here, here and here, I have put together some code which works for single points, but does not for multiple points. See reproducible example below: Libraries and data # libraries library(tidyverse) library(sf) library(rgdal) library(sp) river <- structure(list(FWK_Code = structure(1L, .Label = "1_F461", class = "factor"), FWK_Name = structure(1L, .Label =

问题 Suppose we have three points, a, b, c. b and c are linked to become a line. how to use R to calculate the distance from a to this line? Is there any function? Thanks a lot 回答1: It has to be distinguished whether we are dealing with a two-dimensional or a three-dimensional case. 2D case If the problem is two-dimensional, the position of the points a , b and c can be defined by pairs of numbers which represent the points' x and the y coordinates. The following function can be used to calculate

问题 I have a list of points XY and I want to group them by a given distance, let's say all the points that are at x distance between them should be grouped in different list. Basically if I have A=(0,0), B=(0,1), C=(0,2), I want to group all points that have a maxDistance of 1, in order to obtain :[[A,B],[C]] ; 回答1: I didn't really understand your question, so I'm not really sure how you want to do the grouping, but this might start you off in the right direction, at least. (Written in VB, but

问题 For a while now I've been using the following function to rotate a series of Points around a pivot point in various programs of mine. private Point RotatePoint(Point point, Point pivot, double radians) { var cosTheta = Math.Cos(radians); var sinTheta = Math.Sin(radians); var x = (cosTheta * (point.X - pivot.X) - sinTheta * (point.Y - pivot.Y) + pivot.X); var y = (sinTheta * (point.X - pivot.X) + cosTheta * (point.Y - pivot.Y) + pivot.Y); return new Point((int)x, (int)y); } This has always

问题 I've got a user_sessions table that has a column named "geo_location", it's a POINT column that stores the latitude and longitude values for a user's current location, or NULL if it's not available. When I create a Model in Laravel that binds to that table it only works when the geo_location field is hidden completely. Otherwise it throws a JSON error because it's not properly querying for the separate X and Y values in the geo_location column. Is there a way that I can create an Accessor in

问题 I'd like to create a WPF app that traces the location of the mouse cursor, updating the image in the MouseMove event handler. My original thought was to create a GeometryDrawing and then add paths to that but I'm struggling with how to wire this up in code (though the Xaml for GeometryDrawings seems straightforward). What's the easiest way to wire this stuff up - its just for debugging so I'm not concerned about efficiency. 回答1: What about just using Polyline? Here's the xaml: <Window x:Class

问题 I'd like to create a WPF app that traces the location of the mouse cursor, updating the image in the MouseMove event handler. My original thought was to create a GeometryDrawing and then add paths to that but I'm struggling with how to wire this up in code (though the Xaml for GeometryDrawings seems straightforward). What's the easiest way to wire this stuff up - its just for debugging so I'm not concerned about efficiency. 回答1: What about just using Polyline? Here's the xaml: <Window x:Class

问题 I have a triangle with points A, B, C and Point in space (P). How can I get distance from point to plane? I need to calc distance from P to plane, even when my triangle lie far away(or not above to the point, like on picture). Point and triangle: 回答1: If the point is P(x1,y1,z1) and the plane is ax+by+cz+d = 0 Distance dist = Abs(a*x1+b*y1+c*z1+d) / Sqrt(a^2+b^2+c^2) 回答2: I assume you want to compute perpendicular distance between point and plane given 3 points on it forming a triangle. Here