Namespace pv.Geo.scale#ticks

Tick functions for geographic scales. Because geographic scales represent two-dimensional transformations (as opposed to one-dimensional transformations typical of other scales), the tick values are similarly represented as two-dimensional coordinates in the input domain, i.e., pv.Geo.LatLng objects.

Also, note that non-rectilinear projections, such as sinsuoidal and aitoff, may not produce straight lines for constant longitude or constant latitude. Therefore the returned array of ticks is a two-dimensional array, sampling various latitudes as constant longitude, and vice versa.

The tick lines can therefore be approximated as polylines, either with "linear" or "cardinal" interpolation. This is not as accurate as drawing the true curve through the projection space, but is usually sufficient.
Defined in: GeoScale.js.

Namespace Summary
Constructor Attributes	Constructor Name and Description
	pv.Geo.scale#ticks Abstract; this is a local namespace on a given geographic scale.

Method Summary
Method Attributes	Method Name and Description
	lat(m) Returns latitude ticks.
	lng(m) Returns longitude ticks.

Namespace Detail

pv.Geo.scale#ticks

Abstract; this is a local namespace on a given geographic scale.

See:: pv.Geo.scale; pv.Geo.LatLng; pv.Line#interpolate

Method Detail

{array} lat(m)

Returns latitude ticks.

Parameters:
{number} m Optional: the desired number of ticks.

Returns:: {array} a nested array of pv.Geo.LatLng ticks.

{array} lng(m)

Returns longitude ticks.

Parameters:
{number} m Optional: the desired number of ticks.

Returns:: {array} a nested array of pv.Geo.LatLng ticks.

Classes

Namespace pv.Geo.scale#ticks