daf bit: Moed Katan 2

This week starts a new tractate, about the festival intermediate days. These days do not have the restrictions of Shabbat and festivals (no work, etc), but they are not ordinary days either and they have some limitations.

Today's daf is 3, but I'm going back one page to the very beginning of the tractate.

The mishna begins by talking about irrigating fields. Fields may be watered during the festival intermediate days and also during the sabbatical year (every seventh year, when no crops are planted or harvested). Such watering is permitted from a spring but not from stored rain nor from a well. R. Eleazar b. Azariah says that a water channel may not be dug during the festival or sabbatical; the sages, however, permit it during the sabbatical. Further, an existing channel that becomes damaged may be repaired during the festival, and the sages show particular concern for public welfare: public water works, roads, and mikvaot (ritual baths) may be repaired or cleaned and "all public needs" may be performed. (2a)

two dimensions out of three

It's funny to see (well, hear) my phone's navigator app react to parking garages. "Do X... oh ok you're going north so do Y... oh you're going west so do Z... oh you're going south do A... oh you're going east do X which I'll pretend I haven't said before..." -- iterate until you reach the exit. It doesn't respond to elevation, only latitude/longitude.

I can think of three possible reasons for this, and I wonder which it is (or if it's something else I haven't thought of):

1. The GPS in the phone doesn't detect altitude.

2. The map data (Google's, in this case) doesn't record elevation. It does you no good to know that the GPS is at a certain elevation if the app can't tell that that's 200 feet above the road, after all.

3. The GPS and map data are available, but the app isn't programmed to take it into account. How often does this really come up, after all?