# X and Y after Albers lat and lon transformation

that is probably a very obvious question but it is melting my brain:

when transforming lat and lon to [x,y] (for instance using this code https://gist.github.com/RandomEtc/476238) I get the following: { x: -0.27, y: -1.12 }

What are x and y? Are these radians? How can I use x and y to find the exact point for that lat and lon in may 2D projected map?

Edit:

This is the map I am working with: http://www.jetplan.com/weather/data/maps/eutball06.gif

What I am trying to achieve is to map a (lat,lon) to a (x,y) pixel on that image.

I think the map is an Albers projection.

I have used the code mentioned above to get an x and y value.

My problem is that the (x,y) coordinates I get are related to a unit sphere and I am not sure how am I supposed to map this to a pixel on the image of the map.

• Did the page referenced help? mathworld.wolfram.com/AlbersEqual-AreaConicProjection.html Commented May 11, 2015 at 12:19
• Welcome to GIS SE. Please take a look at the Tour. And please also edit some extra info into the body of the question for clarification: e.g. What are the inputs for the outputs you list? And why quote coords to 15 significant figures? Commented May 12, 2015 at 4:52

To use any formula, you need the parameters of the Albers Equal Area projection:

``````latitude and longitude of origin
first and second parallel
``````

You can guess the longitude from the only meridian that is straightly vertical, but the others are more difficult to get.

You might be better off by using a georeferencing tool. The georeferencer inside QGIS does a good job.