cheap-ruler - npm Package Compare versions

Comparing version 1.0.0 to 1.1.0

bench/bench-bearing.js

@@ -0,1 +1,3 @@
+'use strict';
+
 var Benchmark = require('benchmark');
@@ -12,3 +14,3 @@
 suite
-.add('turf.bearing', function() {
+.add('turf.bearing', function () {
     for (var i = 0; i < lines.length; i++) {
@@ -21,3 +23,3 @@ var line = lines[i];
 })
-.add('ruler.bearing', function() {
+.add('ruler.bearing', function () {
     for (var i = 0; i < lines.length; i++) {
@@ -30,5 +32,5 @@ var line = lines[i];
 })
-.on('cycle', function(event) {
-  console.log(String(event.target));
+.on('cycle', function (event) {
+    console.log(String(event.target));
 })
 .run();

bench/bench-distance.js

@@ -0,1 +1,3 @@
+'use strict';
+
 var Benchmark = require('benchmark');
@@ -12,3 +14,3 @@
 suite
-.add('turf.lineDistance', function() {
+.add('turf.lineDistance', function () {
     for (var i = 0; i < lines.length; i++) {
@@ -18,3 +20,3 @@ turf.lineDistance(turf.linestring(lines[i]));
 })
-.add('ruler.lineDistance', function() {
+.add('ruler.lineDistance', function () {
     for (var i = 0; i < lines.length; i++) {
@@ -24,5 +26,5 @@ ruler.lineDistance(lines[i]);
 })
-.on('cycle', function(event) {
-  console.log(String(event.target));
+.on('cycle', function (event) {
+    console.log(String(event.target));
 })
 .run();

index.js

@@ -76,3 +76,42 @@ 'use strict';
                p[1] <= bbox[3];
+    },
+
+    pointOnLine(line, p) {
+        var minDist = Infinity;
+        var minX, minY;
+
+        for (var i = 0; i < line.length - 1; i++) {
+
+            var x = line[i][0];
+            var y = line[i][1];
+            var dx = (line[i + 1][0] - x) * this.e;
+            var dy = line[i + 1][1] - y;
+
+            if (dx !== 0 || dy !== 0) {
+
+                var t = ((p[0] - x) * this.e * dx + (p[1] - y) * dy) / (dx * dx + dy * dy);
+
+                if (t > 1) {
+                    x = line[i + 1][0];
+                    y = line[i + 1][1];
+
+                } else if (t > 0) {
+                    x += dx * t / this.e;
+                    y += dy * t;
+                }
+            }
+
+            dx = (p[0] - x) * this.e;
+            dy = p[1] - y;
+
+            var sqDist = dx * dx + dy * dy;
+            if (sqDist < minDist) {
+                minDist = sqDist;
+                minX = x;
+                minY = y;
+            }
+        }
+
+        return [minX, minY];
     }
 };

package.json

 {
   "name": "cheap-ruler",
-  "version": "1.0.0",
+  "version": "1.1.0",
   "description": "A collection of fast approximations to common geographic measurements.",
@@ -11,6 +11,8 @@ "main": "index.js",
     "eslint-config-mourner": "^2.0.1",
+    "tape": "^4.5.1",
     "turf": "^2.0.2"
   },
   "scripts": {
-    "test": "eslint index.js"
+    "pretest": "eslint index.js bench test/test.js",
+    "test": "tape test/test.js"
   },
@@ -17,0 +19,0 @@ "eslintConfig": {

README.md

@@ -1,6 +0,6 @@
-# cheap-ruler
+# cheap-ruler [![Build Status](https://travis-ci.org/mapbox/cheap-ruler.svg?branch=master)](https://travis-ci.org/mapbox/cheap-ruler)
 
 A collection of fast approximations to common geographic measurements, along with some utility functions.
-Useful for speeding up analysis scripts when measuring things on a city scale
-by replacing expensive [Turf](http://turfjs.org/) calls in key places.
+Useful for speeding up analysis scripts when measuring things on a city scale,
+replacing [Turf](http://turfjs.org/) calls in key places.
 
@@ -11,5 +11,10 @@ ## Usage
 var ruler = cheapRuler(35.05, 'miles');
+
 var distance = ruler.distance([30.51, 50.32], [30.52, 50.312]);
+var lineLength = ruler.lineDistance(line.geometry.coordinates);
+var bbox = ruler.bufferPoint([30.5, 50.5], 0.01);
 ```
 
+**Note**: to get the full performance benefit, create the ruler object once per an area of calculation (such as a tile), and then reuse it as much as possible.
+
 ### Creating a ruler object
@@ -34,3 +39,3 @@
 
-Given two points of the form `[x, y]`, returns the distance. Typically within 0.1% of `turf.distance` values but 20–25 times faster.
+Given two points of the form `[x, y]`, returns the distance. Typically within 0.1% of `turf.distance` values (on small distances and far away from poles), but 20–25 times faster.
 
@@ -43,7 +48,12 @@ #### lineDistance(points)
 
-Returns the bearing between two points in angles. Typically within 0.001% of `turf.bearing` but 3–4 times faster.
+Returns the bearing between two points in angles. Typically within 0.01% of `turf.bearing` but 3–4 times faster.
 
+#### pointOnLine(line, p)
+
+Returns the closest point on the line from the given point. Line is an array of points. 80-90 times faster than `turf.pointOnLine`.
+
 #### bufferPoint(p, buffer)
 
 Given a point, returns a bounding box object (`[w, s, e, n]`) created from the given point buffered by a given distance.
+This is about _200 times faster_ than creating a bounding box with two diagonal `turf.destination` calls.
 
@@ -50,0 +60,0 @@ ```js

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Improved metrics

Total package byte prevSize

22030

increased by22.98%

Number of package files

12

increased by50%

Lines of code

266

increased by38.54%

Number of lines in readme file

68

increased by17.24%

Worsened metrics

Dev dependency count

5

increased by25%

Number of medium supply chain risk alerts

1

increased byInfinity%

No dependency changes