distance | 易学教程

Calculate distance between Zip Codes… AND users.

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问题 This is more of a challenge question than something I urgently need, so don\'t spend all day on it guys. I built a dating site (long gone) back in 2000 or so, and one of the challenges was calculating the distance between users so we could present your \"matches\" within an X mile radius. To just state the problem, given the following database schema (roughly): USER TABLE UserId UserName ZipCode ZIPCODE TABLE ZipCode Latitude Longitude With USER and ZIPCODE being joined on USER.ZipCode =

How can I find distance traveled with a gyroscope and accelerometer?

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问题 I want to build an app that calculates accurate Distance travelled by iPhone (not long distance) using Gyro+Accelerometer. No need for GPS here. How should I approach this problem? 回答1: Basic calculus behind this problem is in the expression (and similar expressions for displacements in y and z) and basic geometry is the Pythagorean theorem So, once you have your accelerometer signals passed through a low-pass filter and binned in time with sampling interval dt, you can find the displacement

Calculate distance in meters when you know longitude and latitude in java [duplicate]

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问题 Possible Duplicate: Working with latitude/longitude values in Java Duplicate: Working with latitude/longitude values in Java How do I calculate distance between two latitude longitude points? I need to calculate the distance between two points given by two coordinates. The project I am working on is a Java-project, so Java-code will be great, but pseudo-code can also be given, then I can implement it myself :) As you probably know, there are three ways to represent coordinates: Degrees

Should I use px or rem value units in my CSS?

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问题 I am designing a new website and I want it to be compatible with as much browsers and browser settings as possible. I am trying to decide what unit of measurement I should use for the sizes of my fonts and elements, but am unable to find a conclusive answer. My question is: should I use px or rem in my CSS? So far I know that using px isn\'t compatible with users who adjust their base font size in their browser. I\'ve disregarded em s because they are more of a hassle to maintain, compared to

Haversine Formula in Python (Bearing and Distance between two GPS points)

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问题 Problem I would like to know how to get the distance and bearing between 2 GPS points . I have researched on the haversine formula. Someone told me that I could also find the bearing using the same data. Edit Everything is working fine but the bearing doesn\'t quite work right yet. The bearing outputs negative but should be between 0 - 360 degrees. The set data should make the horizontal bearing 96.02166666666666 and is: Start point: 53.32055555555556 , -1.7297222222222221 Bearing: 96

Geographic / geospatial distance between 2 lists of lat/lon points (coordinates)

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问题 I have 2 lists ( list1 , list2 ) with latitude / longitudes of various locations. One list ( list2 ) has locality names that list1 does not have. I want an approximate locality for every point in list1 as well. So I want to take a point in list1 , try to look for the nearest point in list2 and take that locality. I repeat for every point in list1 . It also want the distance (in meters) and the index of the point (in list1 ) so I can build some business rules around it - essentially these are

Should I use px or rem value units in my CSS?

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I am designing a new website and I want it to be compatible with as much browsers and browser settings as possible. I am trying to decide what unit of measurement I should use for the sizes of my fonts and elements, but am unable to find a conclusive answer. My question is: should I use px or rem in my CSS? So far I know that using px isn't compatible with users who adjust their base font size in their browser. I've disregarded em s because they are more of a hassle to maintain, compared to rem s, as they cascade. Some say that rem s are resolution independent and therefore more desirable. But

Shortest distance between a point and a line segment

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问题 I need a basic function to find the shortest distance between a point and a line segment. Feel free to write the solution in any language you want; I can translate it into what I\'m using (Javascript). EDIT: My line segment is defined by two endpoints. So my line segment AB is defined by the two points A (x1,y1) and B (x2,y2) . I\'m trying to find the distance between this line segment and a point C (x3,y3) . My geometry skills are rusty, so the examples I\'ve seen are confusing, I\'m sorry