coordinates | 易学教程

How to detect tap on small nearest buttons in iOS?

阅读更多关于 How to detect tap on small nearest buttons in iOS?

I need to build an app in which there is an image. On image there are many points where user can tap and depend upon that location of tap we need to take input. Tap locations are fixed. User can zoom image. Detect multiple taps. (Single tap, double tap, etc.) Biggest problem we are facing is there are too many points near to each other. So if we tap on one point we are getting other points clicked. Following is the image according which I need to work on. I need to detect tap on all red dots and take decision based upon that. That red dots will not be visible to user. What I have tried is

How to determine the true x y co-ord in a touch event (or mouse event) via javascript?

阅读更多关于 How to determine the true x y co-ord in a touch event (or mouse event) via javascript?

问题 I've been working on touch events and have some code working quite nicely, until the canvas doesn't start at the top left corner. As soon as I add anything before it, the reported event is offset by the position of the canvas. I determine this by drawing a circle around where the touch was. The circle is always offset by the offset of the canvas from top left corner of the screen. Looking at the event for on touch start, I can see that there is a pageY available (within chrome, using usb

Fastest way to determine COUNTRY from millions of GPS coordinates [R]

阅读更多关于 Fastest way to determine COUNTRY from millions of GPS coordinates [R]

问题 I have millions of GPS coordinates and want to quickly add a column of the country of the coordinates. My current method works but is extremely slow: library(data.table) #REPRODUCE DATA data <- data.table(latitude=sample(seq(47,52,by=0.001), 1000000, replace = TRUE), longitude=sample(seq(8,23,by=0.001), 1000000, replace = TRUE)) #REQUIRED PACKAGES if (!require("sp")) install.packages("sp") if (!require("rworldmap")) install.packages("rworldmap") if (!require("sf")) install.packages("sf")

Converting Southing/Easting GPS coordinates to Latitude/Longitude

阅读更多关于 Converting Southing/Easting GPS coordinates to Latitude/Longitude

I am developing a web application using JQuery Framework and am using Geolocation to determine the locations of our hardware stations to display on Google Maps. In our database the locations of the sites are stored in Southing/Easting format. I need a way to convert Southing/Easting coordinates to Latitude/Longitude that Google Maps can understand. Can anyone please tell me the formula or the best way to approach this problem? I have done searches on Southing/Easting however nothing came up, more like northing/westing etc and even then, not much info.. The programming part I don't really need

canvas get points on mouse events

阅读更多关于 canvas get points on mouse events

问题 I am having the following function to get the mouse click positions(coordinates). $('#myCanvas').on('click', function(e) { event = e; event = event || window.event; var canvas = document.getElementById('myCanvas'), x = event.pageX - canvas.offsetLeft, y = event.pageY - canvas.offsetTop; alert(x + ' ' + y); }); I need to get the mouse point on clicking a position and also secound mouse point position after draging the same. ie., mousedown point and mouseup points. 回答1: Try a little different

Cubic bezier curve segment

阅读更多关于 Cubic bezier curve segment

问题 If I have the 4 points describing a Bezier curve P1, P2, P3, P4 (where P1 and P4 are the end points of the curve and P2 and P3 are the control points of the curve), how could I find the points that describes only a segment of this bezier curve? I found this answer which is exactly what I am looking for but the answer seems wrong. If I set t0=0 and t1=1 in the equations which should represent the entire bezier curve, the resulting points are not valid. They are not equal to the original points

Placing child window relative to parent in Tkinter python

阅读更多关于 Placing child window relative to parent in Tkinter python

问题 I have a parent widget which contains a button. When the button is pressed I would like to open a borderless (i.e. no Windows decoration buttons) window directly underneath the parent widget aligned to the left hand side of it. I'm puzzled that the only way (it seems) of setting the position of a window is using .geometry() but worse, I can't seem to get the absolute coordinates of the parent widget - which I need for .geometry() , only the offsets from the parent's parent. So far my code is:

Android - How to determine whether coordinates lie on road in Google Maps

阅读更多关于 Android - How to determine whether coordinates lie on road in Google Maps

问题 I need to make a check in my application that determines whether the given coordinates lie on road or not in Google Maps. Is there any function in Google Maps API that can aid me with that? Thanks in advance! 回答1: As far as I know this can't be done using the Google Maps API. I think your best bet is to use a crowd-sourced dataset such as OpenStreetMap (OSM). You'd need to set up your own spatial database (e.g., PostGIS) and import OSM data into the database. Then, you'd create a server-side

Android: Placing a view in an arbitrary location

阅读更多关于 Android: Placing a view in an arbitrary location

I have been trying to place a view in an arbitrary location. My aim: To overlay some rectangle of a JPG/PNG, given coordinates that relate to the JPG/PNG , with some other view, say, Gallery, or some video. I don't want to use AbsoluteLayout, as it is depricated. Therefore, I am using RelativeLayout, defining a dummy textbox as a placeholder, and putting my view RIGHT_TO and BELOW the textbox. +--------+ |TextView| | | (x,y) +--------+-----------------------+ | | | My View | | | +-----------------------+ My question is: Is there a more robust and elegant way to do that? The problem with the

Calculate 3D point coordinates using horizontal and vertical angles and slope distance

阅读更多关于 Calculate 3D point coordinates using horizontal and vertical angles and slope distance

I am trying to learn how to calculate the XYZ coordinates of a point using the XYZ coordinates of an origin point, a horizontal and vertical angle, and 3d distance. I can make the calculations simply by projecting the points onto 2D planes, but is there a more straightforward way to do this in 3D? I am trying to understand how a surveying total station calculates new point locations based on it's measured location, the 3d (slope) distance that it measures to a new point, and the measured horizontal and vertical angles that sight onto the new point location. Thanks, E Brett Hale Just a note on