zoom.filter([filter]) If filter is specified, sets the filter to the specified function and returns the zoom behavior. If filter is not specified, returns the current filter, which defaults to: function filter() { return !event.button; } If the filter returns falsey, the initiating event is ignored and no zoom gestures are started. Thus, the filter determines which input events are ignored. The default filter ignores mousedown events on secondary buttons, since those buttons are typically

arc.innerRadius([radius]) If radius is specified, sets the inner radius to the specified function or number and returns this arc generator. If radius is not specified, returns the current inner radius accessor, which defaults to: function innerRadius(d) { return d.innerRadius; } Specifying the inner radius as a function is useful for constructing a stacked polar bar chart, often in conjunction with a sqrt scale. More commonly, a constant inner radius is used for a donut or pie chart. If th

line.context([context]) If context is specified, sets the context and returns this line generator. If context is not specified, returns the current context, which defaults to null. If the context is not null, then the generated line is rendered to this context as a sequence of path method calls. Otherwise, a path data string representing the generated line is returned.

transition.filter(filter) For each selected element, selects only the elements that match the specified filter, and returns a transition on the resulting selection. The filter may be specified either as a selector string or a function. If a function, it is evaluated for each selected element, in order, being passed the current datum d and index i, with the this context as the current DOM element. The new transition has the same id, name and timing as this transition; however, if a transition

d3.symbolCross The Greek cross symbol type, with arms of equal length.

d3.isoFormat The full ISO 8601 UTC time formatter. Where available, this method will use Date.toISOString to format.

d3.easeLinear(t) Linear easing; the identity function; linear(t) returns t.

projection.fitExtent(extent, object) Sets the projection’s scale and translate to fit the specified GeoJSON object in the center of the given extent. The extent is specified as an array [[x₀, y₀], [x₁, y₁]], where x₀ is the left side of the bounding box, y₀ is the top, x₁ is the right and y₁ is the bottom. Returns the projection. For example, to scale and translate the New Jersey State Plane projection to fit a GeoJSON object nj in the center of a 960×500 bounding box with 20 pixels of paddi

transition.attrTween(name[, factory]) If factory is specified and not null, assigns the attribute tween for the attribute with the specified name to the specified interpolator factory. An interpolator factory is a function that returns an interpolator; when the transition starts, the factory is evaluated for each selected element, in order, being passed the current datum d and index i, with the this context as the current DOM element. The returned interpolator will then be invoked for each f

transition.tween(name[, value]) For each selected element, assigns the tween with the specified name with the specified value function. The value must be specified as a function that returns a function. When the transition starts, the value function is evaluated for each selected element, in order, being passed the current datum d and index i, with the this context as the current DOM element. The returned function is then invoked for each frame of the transition, in order, being passed the e