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Now it's been 3 days I am using Mapinfo and it has Y as latitude and X as longitude. Is that the same case for all mapping software? As for any country their respective value is multiple of 1 or -1. So for Nepal can I say it is on positive side +1 for both latitude and longitude? And for USA to be +1 Y and -1 X.

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Latitude is the Y axis, longitude is the X axis. Since latitude can be positive and negative (north and south of the Equator), and longitude can be as well (negative west of Greenwich and positive eastward) when the -180 to +180 longitude system is use. Hence the four combinations of positive and negative are possible depending upon where you are located on the globe. –  Dan Patterson Jun 29 '11 at 22:19
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You will appreciate an earlier thread that discusses this question more generally: gis.stackexchange.com/questions/6037/…. –  whuber Jun 29 '11 at 22:46
    
See also gis.stackexchange.com/questions/99769/… –  martin f Jun 11 at 23:25

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up vote 8 down vote accepted

No, for example when talking to a GeoServer WFS (or any other compliant WFS) the axis order depends on if you ask for version 1.0 or 1.1 of the spec in EPSG:4326.

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Could you please elaborate ? –  kinkajou Jun 29 '11 at 22:39
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The original spec had longitude,latitude order. This is more of a software-oriented view as it matches up with [US-centric] x,y order. This doesn't match the ISO standard, so various later specs have changed the order to latitude,longitude. This order should be used when displaying or transmitting the values, they don't have to be stored that way. Not everyone uses x,y as the labels for easting,northing. Some people use y=easting,x=northing. For projected data, the coordinate reference system defn should specify the axis order and labels. –  mkennedy Jun 30 '11 at 0:43
    
@mkennedy Although the US convention may be (long, lat), that does not make such a convention "US-centric." This actually is the international and very long established convention in mathematics and physics. It is based on the concept of orientation of a coordinate system in which (long, lat) agrees with the conventional positive (x,y,z) orientation of 3D Cartesian coordinates when an outward-pointing normal direction (i.e., "up") is used for the third coordinate on the sphere. –  whuber Mar 31 at 16:00

For ESRI its almost always going to be:

Lat = Y Long = X

It's easy to get backwards. I've been doing this for years but still need to think about it sometimes.

On a standard north facing map, latitude is represented by horizontal lines, which go up and down (North and South) the Y axis. Its easy to think that since they are horizontal lines, they would be on the x axis, but they are not.

So similarly, the X axis is Longitude, as the values shift left to right (East and West) along the X axis. Confusing for the same reason since on a north facing map, these lines are vertical.

I'm mildly dyslexic so I always need to pause and think about it for a brief second when displaying new x/y data. Hope this helps.

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This is confusing: by definition, "horizontal" means level: such lines extend from side to side, not up and down. Horizontal lines are lines of constant latitude; latitude varies in a vertical direction: your description could be read as just the reverse. You might find the historical reason for these terms to be of interest. –  whuber Aug 16 '13 at 1:45

X and Y are variables that can change for different purposes. For example: You may want to know the wind-speed, and you could use a sailboat's speed to know how fast is the wind going, so we can say: the sailboat = X and wind = Y. But it could also be that, you don't know how fast is the boat going and you can find its speed by knowing the wind-speed so now wind = X and sailboat = Y. However: The Equator, Prime meridian (at Greenwich), North and South, and Latitude and Longitude don't change. From the Equator to the North pole we measure Latitude 0° to 90° respectively, from the Equator to the South pole we measure 0° to -90° respectively. From the prime meridian at 0° we measure West up to -180° and East up to 180°. Sometimes -+ are replaced with West and East so that: -81° and 81°W mean the same thing. ESRI corporation regularly use X as longitude and Y as latitude.

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In this question "X" is shorthand for the first element of an ordered pair of coordinates and "Y" for the second element. –  whuber Sep 18 '13 at 22:37

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