I'm not too familiar with the D3 mercator projection function, and I'm getting some unexpected results. I'd like to project the following latitude and longitude (somewhere in Mexico):

var geo = [19, -99]

I define my mercator projection using d3

var projection = d3.geo.mercator();
projection(geo)
> [529.7418836818384, NaN]

which is a point obviously not on a map. What exactly am I doing wrong? Thanks!

I'm not too familiar with the D3 mercator projection function, and I'm getting some unexpected results. I'd like to project the following latitude and longitude (somewhere in Mexico):

var geo = [19, -99]

I define my mercator projection using d3

var projection = d3.geo.mercator();
projection(geo)
> [529.7418836818384, NaN]

which is a point obviously not on a map. What exactly am I doing wrong? Thanks!

• javascript
• d3.js
• mercator

Share Improve this question Follow asked Nov 17, 2013 at 2:55 MichaelMichael 7,3972121 gold badges5555 silver badges8585 bronze badges

Add a ment  | 

1 Answer 1

Sorted by: Reset to default 10

Javascript has it's lat and long round the opposite way to the rest of the world, so what you've given D3 is a longditue of 19 and a latitude of -99. Obviously there is no latitude of -99 hence the NaN. Now if you just reverse your geo variable to

var geo = [-99, 19]

all should be good.