Difference between desire (chanda) and craving (tanha)?

Chanda is acceptation to do something to an object. However, it is not decision (adhimokkha), or attachment (taṇhā). In vinaya pitaka, it often use as "agreement" (i.e.).

There are:

1. Unwholesome chanda
   1. Unwholesome chanda without tanṇhā
   2. Unwholesome chanda with sensual tanṇhā
   3. Unwholesome chanda with becoming tanṇhā
   4. Unwholesome chanda with unbecoming tanṇhā
2. Resultant chanda
   1. Lokiya resultant chanda
   2. Lokutara resultant chanda
3. Ineffective action chanda
   1. Ineffective action chanda of sekkha (puthujana and 3 noble one)
   2. Ineffective action chanda of asekkha (arahanta)
4. Wholesome chanda
   1. Lokiya wholesome chanda
   2. Lokutara wholesome chanda

See Conation in Sangaha chapter 2.