how do you set projections for city level geographies

Question

I've asked similar questions before and I'm still struggling.

I want to create geo based info graphics at the level of a city.

I need to be able to take some latitude/longitude values and project them such that they are centered and appropriately zoomed.

It would help me a great deal to see an example that plots a small number of points.

This is roughly an L shape and all three points should be in San Francisco.

It could be as simple as 3 black dots on a white background. I hope to learn:

which projection?
how do you adjust the projection so that an area the size of San Francisco is on the canvas?
how do you translate those coordinates and position them on that canvas?

Could someone create such an example?

Thanks.

-Kelly

Have you seen [this question](http://stackoverflow.com/questions/14492284/center-a-map-in-d3-given-a-geojson-object)? — Lars Kotthoff, Mar 23 '14 at 01:17
Yes, I've seen that. Thank you. One problem is that I don't have or need paths or shape files and that question uses shape files to discover the bounding box. I really hope to see a simple example that includes the lat/longs as data. I suspect that the trouble I'm having is simple - like I need to convert my lat/longs in some way, swap and/or negate them. — kellyfelkins, Mar 23 '14 at 16:23
I guess I'm looking for a geo example that is at the city level that doesn't use shape files. — kellyfelkins, Mar 23 '14 at 16:33

score 0 · Answer 1 · answered Mar 24 '14 at 15:05

I created a simple example that works.

I think I was making multiple mistakes that made it really difficult to correct.

In case others have troubles too, here are some things to watch out for:

The projection method expects an array. For a while I was passing it 2 arguments, but it needs a single argument that is an array.
The projection expects the values in longitude, latitude order.

-Kelly

1 Answers1