Accept points as well as polygons as input

[mem48]

In some cases, you may have OD data between a zone and a point. E.g. travel to school starts somewhere in the zones but all trips finish at a defined point.

Currently inputting a point into the zones_d argument returns

Error in st_cast.POINT(X[[i]], ...) : 
  cannot create MULTIPOLYGON from POINT

[mem48]

Semi-realted If you use subpoints for origins then you must use subpoints for destinations. In my case, there is no sub-point just a single point.

[Robinlovelace]

Duplicate of #25

There is already a work-around which I developed for CRUSE: #31

I created a small e.g. 100 m buffer around each school and passed those to zones_d. Any reproducible example, or even better improvements to the documentation/code welcome.

[dabreegster]

Emma's hit this problem as well. In the short term, the workaround is to make a zone for each school point and make the polygon be a small circle around the point. odjitter itself could be more flexible here though.