Hello,

I’ve been trying to use d3.geoGraticule with d3.zoom to create a zoomable map with graticules with the following code (where transform is the current zoom.transform):

```
const tmin = projection.invert(transform.apply([0,0]));
const tmax = projection.invert(transform.apply([width, height]));
const stepScale = scaleLinear().domain(zoomExtent).range([minStep,maxStep]);
const k = stepScale(transform.k);
const graticules = geoGraticule().extent([tmin, tmax]).step([k, k])();
```

This results in graticules that stick at one in a single position, while zooming moves the rest to that position.

Any help would be much appreciated.