ibeacon distance

The formula is as follows, unit meters:1th latitude and Longitude: lng1 LAT12nd latitude and Longitude: lng2 lat2Round (6378.138*2*asin (sqrt (POW (LAT1*PI ()/180-lat2*pi ()/180)/2), 2) +cos (Lat1*pi ()/180) *cos (LAT2*PI ()/180) * Pow (Sin ((Lng1*pi ()/180-lng2*pi ()/180)/2), 2)) *1000)For example:SELECT Store_id,lng,lat, ROUND (6378.138*2*asin (SQRT (POW (22.299439*pi ()/180-lat*pi ()/180)/2, 2) +cos ( 22.299439*pi ()/180) *cos (Lat*pi ()/180) *pow (SIN ((114.173881*pi ()/180-lng*pi ()/180)/2)

I sorted out several good blogs. Basic concepts of statistics Variance: Obviously, the mean value describes the intermediate point of the sample set. It tells us that the information is very limited, the standard deviation describes the average distance from each sample point to the mean of the sample set. Take the two sets as an example. For example, [,] and [,], the mean values of the two sets are 10, but obviously the difference between the two set

In the process of data analysis and data mining, we often need to know the size of differences between individuals, and then evaluate the similarities and categories of individuals. The most common is the analysis of data, classification and clustering algorithms in data mining, such as K nearest neighbor (KNN) and K-means (K-means). Of course there are many ways to measure individual differences, and here's a list.To facilitate the following explanations and examples, we first set out to compar

first, the outsetRegistered in the blog for three years, today decided to write the first blog, warning yourself not lazy!!!second, about the ArcGIS JS version selectionAt the time of writing this blog, the official version of ArcGIS JS 4.0 has been Released. It is different from the 3.x version, the map is not a control, and really just a "graph", map (4.0 Version) needs to be shown in a view, in the Mapview is a plan, in the sceneview inside a three-dimensional map. The same map can show diffe

A work title: known to Beijing, Shanghai, Guangzhou, Kunming and Xi ' an five city route map. To achieve: 1) find the shortest route from Beijing to Kunming. 2) to find Beijing to Kunming, must approach the path of Shanghai. 3) find Beijing to Kunming, must approach Shanghai, but can not go to the path of Guangzhou. Beijing Shanghai Guangzhou Kunming Xian Beijing Shanghai 1462

ArticleDirectory Distance metrics Manhattan distance Taxi distanceTaxicab GeometryOrManhattan distanceCity block distance,Manhattan distance, OrManhattan Length Distance from Manhattan-the distance between two p

Autonomous Learning is a basic feature of distance education. Autonomous Learning means that students can make free and flexible arrangements or choices for learning. The basic motivation and purpose of the emergence and development of distance education is to effectively implement the arrangement and selection of students. Therefore, in this sense, students' autonomous learning is the core concept of

SQL statements: Select Location.* from (select *,round (6378.138*2*asin (sqrt () (Pow () (Sin (36.668530*pi ()/180-px_lat*pi ()/180)/2), 2) +cos (36.668530*pi ()/180) *cos (Px_lat*pi ()/180) * POW (Sin ((117.020359*pi ()/180-px_lon*pi ()/180)/2), 2)) (*1000)) As distance from bsx_training where (px_state = 1) and (type_id! = ") and (((Px_lat >= 27.683290277922) and (px_l At Ignore the above SQL statement first. One by one explanationSQL statements so

correlation coefficient .If the angle cosine formula is written:Represents the angle cosine between the vector x and the vector y, the Pearson correlation coefficient can be expressed as:Pearson correlation coefficients have translational invariance and scale invariance, and the correlation of two vectors (dimensions) is calculated.Implementations in Python:Import NumPy as Npx=np.random.random (y=np.random.random)# method One: Solve the x_=x-Np.mean (x) y based on the formula _=y-Np.mean (y) D1

Currently, the coordinates of user P are: (116.63255, 39.90467), and the current database has 40 million user coordinates which are not fixed. Business Requirements: all users in the center of "P" and "1km" are sorted by distance from near to far, how do I write MYSQL, PHP, or MYSQL stored procedures (if any )?... Now there is user P whose coordinates are :( 116.63255, 39.90467), The current database has 40 million user coordinates is not fixed. Busi

publicclassgeoutil{/** * returns a rectangular range based on latitude and longitude **@ paramlng* Longitude * @param lat* Latitude * @param distance* distance (in meters) * @return [lng1,lat1,lng2,lat2] lower-left corner of the rectangle ( LNG1,LAT1) and upper right Corner (LNG2,LAT2) */publicstatic double[]getrectangle (doublelng,doublelat,longdistance) { floatdelta=111000;if (lng!=0lat!=0) { doublelng

Compilation Environment:Operating system: Win8.1 64-bitIDE platform: Visual Studio UltimateFirst, the principleThe distance s1,s2,s3 is observed on the point p to be measured, and the plane coordinates of P are determined:Second, the Code implementationDistance to the rear intersection. javaPackage Text;import Java.awt.*;import Java.awt.event.*;import java.math.*;import javax.swing.*;import Javax.swing.border.border;public class

Minimum edit distance Solution 1: Determine the similarity of different strings. A set of operation methods are defined to make the two strings different from each other the same. The specific operation method is as follows: 1. modify a character (for example, replace "A" with "B ") 2. Add a character (for example, change "abdd" to "aebdd ") 3. delete a character (for example, change "traveling" to "traveling ") Definition: defines the minimum numbe

Spatial analysis, the most important concept is the distance, different distances will lead to different results. In the study, there is a concept called "spatial scale", this is interested, please self-Baidu (the usual: Baidu know things don't ask me).Therefore, in the study of clustering, the most important thing is to determine the distance between the different data, otherwise it will be as follows:In c

CREATE DEFINER=`root`@`%` FUNCTION `f_getdistance`(in_from_x decimal(10,3), in_from_y decimal(10,3),in_to_x decimal(10,3),in_to_y decimal(10,3)) RETURNS decimal(20,10)BEGINdeclare line LineString;#select CONCAT('LineString(',in_from_x,' ',in_from_y,',',in_to_x,' ',in_to_y,')');RETURN GLength(GeomFromText( CONCAT('LineString(',in_from_x,' ',in_from_y,',',in_to_x,' ',in_to_y,')') )) * 111000;END Http://www.cnblogs.com/ycsfwhh/archive/2010/12/20/1911232.htmlCalculate the

The following describes the editing distance; 1. The distance between string a and string B is the number of steps required to change string a to string B. Only insert, delete, and replace operations are required. 2. First, let's observe the nature of levenshtein distance. D (x, y) indicates the levenshtein distance f

Calculate distance based on two-point latitude and longitudeHow are these longitude determined? The earth is constantly spinning around its axis (the earth's axis is a center of the north-south poles and the Earth.Imaginary line), in the Earth's waist draw a large circle perpendicular to the axis, so that each point on the circle and the North and south poles of the same distance, this circleIt is called "t

[Autohome with car skills] The rearview mirror is a simple and important part of the car, in the daily driving, the rearview mirror, especially the external mirror use frequency is absolutely the highest, relative to the rearview mirror is easy to be overlooked, even some friends never use the interior rearview mirror. In the previous article we introduced the use of external mirrors and determine the distance between the method, "Click here to see th

"The furthest distance in the world" the furthest distance in the world, the furthest distance in the Earth is not the distance between life and death is not the right from birth to the end. It's the way I stand before you it's when I Stand in front of your you don't know I love you yet you don ' t understand I loves y

Similarity measurement or distance functions are very important for algorithms such as clustering and nearby search. As mentioned above, page deduplication is also an example of similarity applications. However, how to define a proper similarity or distance function depends entirely on the task at hand. Generally, defining a distance function d (x, y) must meet t