# 02: Ein Ziel auf der Karte setzen oder löschen

**What to build:** A tap on the Karte deletes the nearest Ziel when one lies within 44 px, and otherwise adds a Ziel at that point. The new Ziel is written as a Koordinate to the metre, appears at the top of the list, and the view stays where it is. A tap on the Standort adds a Ziel there when no Ziel is within 44 px. A tap that no Blatt covers changes nothing. Dragging still pans the Karte. This works without a separate mode.

**Blocked by:** 01: Mehrere Ziele behalten

**Status:** ready-for-agent

The session contract in the spec is the seam. This ticket owns `tap(point)`. Near means within 44 screen pixels at the current scale, inclusive. A repeated Koordinate uses the same notice as a typed repeat. A point no Blatt covers does not set a notice.

- [x] A tap within 44 px of a Ziel deletes the nearest one, at every scale. When two Ziele are equally near, the newer one is deleted.
- [x] A tap farther than 44 px from every Ziel adds a Ziel at that point, as a Koordinate to the metre, at the top of the list, and does not move the view.
- [x] A tap on the Standort adds a Ziel there when no Ziel is within 44 px.
- [x] A tap on a point that no Blatt covers leaves the list and the view unchanged.
- [x] A repeated Koordinate from a tap is treated like a repeated typed Koordinate: the list and the view stay unchanged.
- [x] Dragging pans the Karte. There is no separate mode for setting or deleting a Ziel.

## Comments

The person taps the Karte to add a red Ziel or to remove the one under the finger. The list from 01 gains or loses that row, and the view stays put.