Util

Summary

Util
Functions
distVincenty	Given two objects representing points with geographic coordinates, this calculates the distance between those points on the surface of an ellipsoid.
destinationVincenty	Calculate destination point given start point lat/long (numeric degrees), bearing (numeric degrees) & distance (in m).
Constants
INCHES_PER_UNIT	{Object} Constant inches per unit -- borrowed from MapServer mapscale.c derivation of nautical miles from http://en.wikipedia.org/wiki/Nautical_mile Includes the full set of units supported by CS-MAP (http://trac.osgeo.org/csmap/) and PROJ.4 (http://trac.osgeo.org/proj/) The hardcoded table is maintain in a CS-MAP source code module named CSdataU.c The hardcoded table of PROJ.4 units are in pj_units.c.
DOTS_PER_INCH	{Integer} 72 (A sensible default)
IS_GECKO	{Boolean} True if the userAgent reports the browser to use the Gecko engine
CANVAS_SUPPORTED	{Boolean} True if canvas 2d is supported.
BROWSER_NAME	{String} A substring of the navigator.userAgent property.
Functions
getScrollbarWidth	This function has been modified by the OpenLayers from the original version, written by Matthew Eernisse and released under the Apache 2 license here:
getFormattedLonLat	This function will return latitude or longitude value formatted as

Functions

distVincenty

OpenLayers.Util.distVincenty = function( p1,

p2 )

Given two objects representing points with geographic coordinates, this calculates the distance between those points on the surface of an ellipsoid.

Parameters

p1	{OpenLayers.LonLat} (or any object with both .lat, .lon properties)
p2	{OpenLayers.LonLat} (or any object with both .lat, .lon properties)

Returns

{Float} The distance (in km) between the two input points as measured on an ellipsoid. Note that the input point objects must be in geographic coordinates (decimal degrees) and the return distance is in kilometers.

destinationVincenty

OpenLayers.Util.destinationVincenty = function( lonlat,

brng,

dist )

Calculate destination point given start point lat/long (numeric degrees), bearing (numeric degrees) & distance (in m). Adapted from Chris Veness work, see http://www.movable-type.co.uk /scripts /latlong-vincenty-direct.html

Parameters

lonlat	{OpenLayers.LonLat} (or any object with both .lat, .lon properties) The start point.
brng	{Float} The bearing (degrees).
dist	{Float} The ground distance (meters).

Returns

{OpenLayers.LonLat} The destination point.

Constants

INCHES_PER_UNIT

{Object} Constant inches per unit -- borrowed from MapServer mapscale.c derivation of nautical miles from http://en.wikipedia.org/wiki/Nautical_mile Includes the full set of units supported by CS-MAP (http://trac.osgeo.org/csmap/) and PROJ.4 (http://trac.osgeo.org/proj/) The hardcoded table is maintain in a CS-MAP source code module named CSdataU.c The hardcoded table of PROJ.4 units are in pj_units.c.

DOTS_PER_INCH

{Integer} 72 (A sensible default)

IS_GECKO

{Boolean} True if the userAgent reports the browser to use the Gecko engine

CANVAS_SUPPORTED

{Boolean} True if canvas 2d is supported.

BROWSER_NAME

{String} A substring of the navigator.userAgent property. Depending on the userAgent property, this will be the empty string or one of the following:

”opera” -- Opera
”msie” -- Internet Explorer
”safari” -- Safari
”firefox” -- Firefox
”mozilla” -- Mozilla

Functions

getScrollbarWidth

OpenLayers.Util.getScrollbarWidth = function()

This function has been modified by the OpenLayers from the original version, written by Matthew Eernisse and released under the Apache 2 license here:

http://www.fleegix.org /articles /2006 /05 /30 /getting-the-scrollbar-width-in-pixels

It has been modified simply to cache its value, since it is physically impossible that this code could ever run in more than one browser at once.

Returns

{Integer}

getFormattedLonLat

OpenLayers.Util.getFormattedLonLat = function( coordinate,

axis,

dmsOption )

This function will return latitude or longitude value formatted as

Parameters

coordinate	{Float} the coordinate value to be formatted
axis	{String} value of either ‘lat’ or ‘lon’ to indicate which axis is to to be formatted (default = lat)
dmsOption	{String} specify the precision of the output can be one of: ‘dms’ show degrees minutes and seconds ‘dm’ show only degrees and minutes ‘d’ show only degrees

Returns

{String} the coordinate value formatted as a string