coordinate-systems

问题 I'm trying to draw a dashed line on a google map, so I can't use eshape.js. I need to create an array of points that approximate an elipse in a coordinate system. It's just for display so it doesn't have to be that precise. If someone can just explain the math that's fine. Extra credit if you apply it in javascript ;) 回答1: This is now something you can do within the Google Maps API. Recently, Google added Symbols to Polylines, allowing you to use SVG to style your lines: https://developers

问题 strange, a question which I thought I had responded and actually no! All my GIS datas are well load in netlogo ! The layers are well aligned but xcor and ycor of agents are false false in light of the real world coordinates (e.i. img). During sensibility analyse I whant than agents write their coordinated in a text file because I doesn't whant to deal with hundreds of shapefiles, so need to have the true GIS xcor and ycor in my agents. My code : set buildings gis:load-dataset "../data_gis

问题 I have a grid I have converted from GeoTIFFs to a shapefile. I would like to convert and export the shapefile as a GeoPackage and change the projection so it uses the British National Grid as the geographic coordinate system when opened in a GIS. However this only seems to work using sp and not sf (which does not appear to retain aspects like the datum). This is a problem as I would like to export GeoPackages containing multiple layers which you can only currently do in sf and not sp . Am I

问题 I have a child node added to another node. I want to get the child nodes position with respect to the views coordinates and not the parent nodes coordinates 回答1: Get the child node's position with respect to its parent, then use the convertPoint:fromNode: or convertPoint:toNode: method to convert from the parent node's coordinate system to the scene's coordinate system. (Remember, SKScene inherits from SKNode and is the root of the node hierarchy, so you can use it with either of those

问题 I have a child node added to another node. I want to get the child nodes position with respect to the views coordinates and not the parent nodes coordinates 回答1: Get the child node's position with respect to its parent, then use the convertPoint:fromNode: or convertPoint:toNode: method to convert from the parent node's coordinate system to the scene's coordinate system. (Remember, SKScene inherits from SKNode and is the root of the node hierarchy, so you can use it with either of those

问题 I am using flat topped hexagonal grid (following the manual listed here http://www.redblobgames.com/grids/hexagons/). I need to convert my cube coordinates into pixel coordinates. I have read Hexagonal Grid Coordinates To Pixel Coordinates but the solution listed there requires some modifications to work with flat topped grid. The logic must be similar to the one described in the question linked above but I can't work it out. Definitely in case of flat top hexes x-coordinate may be used as x

问题 I want to create plots from Python of 3D coordinate transformations. For example, I want to create the following image (generated statically by TikZ): A bit of searching led me to the following program: import numpy as np from matplotlib import pyplot as plt from mpl_toolkits.mplot3d import Axes3D from matplotlib.patches import FancyArrowPatch from mpl_toolkits.mplot3d import proj3d class Arrow3D(FancyArrowPatch): def __init__(self, xs, ys, zs, *args, **kwargs): FancyArrowPatch.__init__(self,

问题 I have written a small code to convert the device co-ordinates into world co-ordinates by multiplying the Rotation matrix(using getRotationMatrix) and the vector (Ax,Ay,Az) which are the accelerometer values. When I run this, and the phone is static, I get a very fluctuating value for the Z axis(from 9.3 to 10.3) and the other two are 0. However when I give the phone some acceleration in any direction , it still doesn't show any change to those values and they remain zero. This is the part of

问题 I'm still implementing a perspective projection for my augmented reality application. I've already asked some questions about the viewport-calculation and other camera stuff, which is explained from Aldream in this thread However, I don't get any useful value at the moment and I think this depends on my calculation of the cartesian coordinate space. I had some different ways to transform latitude,longitude and altitude to a cartesian coordinate space, but nothing of them seems to work

问题 Does the method for computing the cross-product change for left handed coordinates? 回答1: The formula for the cross product of the vectors (x1, x2, x3) and (y1, y2, y3) is z1 = x2 * y3 - x3 * y2 z2 = x3 * y1 - x1 * y3 z3 = x1 * y2 - x2 * y1 It is designed in a way that the three vectors x , y and z in the given order have the same handedness as the coordinate system itself. This property does not depend on the handedness of the coordinate system -- for a left-handed coordinate system the