Table of Contents

Time overlays on the map

Status: Built (2026-10-31): D1–D13; Q1–Q5 settled in §7. Slices 1–2 in PR #1199, slices 3–4 in the follow-up PR. Follows the Timeline epic #707: the map stamp (#713 B4), the Time HUD (#712, PR #727) and Display Not Real Time (#993). Touches Views/TimeHudView.axaml, MainWindow.axaml, ViewModels/MainViewModel.cs, ViewModels/TimelineViewModel.cs and the readout row of Views/TimelineView.axaml.

A user with weather wind barbs on the map reported two problems:

  1. The map shows the same time twice. Top left: ● 10/31/2026 2:00 PM · in 23 min. Bottom centre: PINNED | 10/31/2026 2:00 PM in 23 min | ‹ › | Live | ▭.
  2. The bottom bar changes width when the time is stepped. It's centred, so ‹ and › move under the pointer. A second click on › can land on ‹ or Live and undo the step.

This note explains why each overlay exists, why they now overlap, and why the bar moves. It then proposes numbered decisions an implementation PR can follow.

1. What's there today

1.1 The two overlays

Map stamp Time HUD
Where Top left, 12 px in (MainWindow.axaml:648–678) Bottom centre, 14 px above the edge (MainWindow.axaml:630–636, Views/TimeHudView.axaml)
Added by #713 B4 (slice 1) #712 (slice 6, PR #727)
Purpose A read-only caption, so the map (and any capture of it) says which time it shows while the Timeline dock holds the controls The Timeline's everyday controls while the dock is closed, so nothing larger than a 40 px bar sits over the map
Interactive No (IsHitTestVisible="False") Yes: time (focuses the bar for ←/→), ‹ ›, Live, dock toggle; message chip with an action
Text StampText (TimelineViewModel.cs:362–370) ModeLabel, CurrentTimeLabel, OffsetText, drawing… (TimeHudView.axaml:118–154)
Visible when IsMapStampVisible => Timeline.IsNotRealTime \|\| (Timeline.IsActive && IsBottomDockShown) (MainViewModel.cs:387) IsTimeHudVisible => Timeline.IsActive && !(IsBottomDockShown && IsTimelineTabSelected) (MainViewModel.cs:381)

As designed in #712/#713, the two were mutually exclusive. The stamp shows while the dock is open and the HUD is hidden, and the HUD shows while the dock is closed. Both are inside MapArea, so capture_app_screenshot region Map (Services/AppScreenshotProvider.cs:60) includes whichever one is shown.

1.2 What each one shows, by state

The time format follows the Local/UTC preference (TimeFormatting.Format, ActiveFormat).

State Map stamp Time HUD bar
Live, dock closed hidden [● LIVE] 10/31/2026 2:00 PM now │ ‹ › │ ▭
Pinned future, dock closed hidden [PINNED] 10/31/2026 2:00 PM in 23 min │ ‹ › [Live] │ ▭
Pinned past, dock closed hidden [PINNED] 10/31/2026 8:00 AM 5 h 37 ago │ ‹ › [Live] │ ▭
Drawing a new time grey dot, 10/31 1:00 PM · drawing 2:00 PM… adds drawing… before the separator
Dock open, Timeline tab ● LIVE · … or ● … · in 23 min hidden
Dock open, Logs or Clearance tab shown shown (the dock toggle then switches the dock to Timeline, MainViewModel.cs:1500–1508)
Pinned with S-124 / dated S-101 data (IsNotRealTime) always shown: Display Not Real Time · … · in 23 min shown too while the Timeline tab isn't visible
Window < 900 px dock hidden (DockMinimumWindowWidth, MainViewModel.cs:344) HUD is the only control; the dock toggle stays but is disabled
Map < 640 px / < 540 px — drops the offset, then the PINNED pill (TimeHudView.axaml.cs:17–20, .axaml:76–82)

The bottom dock's own readout row (Views/TimelineView.axaml:283–412) has a mode pill, the time and the offset on the left. On the right it has ⏮ ‹ [step menu] › ⏭ [Go live] [window preset].

2. Problems

2.1 Why both overlays show (complaint 1)

The overlap is a regression, not a design choice. The two rules drifted apart:

  • #922 (Clearance tab, 2026-10-12) gave the bottom dock more than one tab. It changed the HUD rule to "hidden only while the dock shows the Timeline tab" (ed74cfb1, MainViewModel.cs:381). That's right: on the Clearance or Logs tab the Timeline controls are gone, so the HUD comes back. But the stamp rule still says "shown while the dock is shown", whatever the tab. With the Logs tab open (the new Logs panel, #1080, makes this common), the map gets both.
  • #993 (2026-10-18) made the stamp stay visible "always while the display isn't real time" (S-98 §12.7.2). With the dock closed, the HUD is also shown, so a pinned map with navigational warnings has both, and the stamp is the only one that says Display Not Real Time.

The screenshot shows a plain stamp (no Display Not Real Time) over weather data, which isn't date-dependent. So it's the first case: the dock was open on a non-Timeline tab.

2.2 Why the bar moves under the pointer (complaint 2)

The bar is a horizontal StackPanel in a Panel with HorizontalAlignment="Center" (TimeHudView.axaml:85, 114, 116). Its width is the sum of its children, and several of them change size or appear when the time changes. Any width change ΔW moves the left edge by ΔW/2. A control at the left also moves by however much the content before it grew.

Children that change on a step (rough widths at 12–13 px):

Child Live → Pinned (› pressed) Changes while stepping
Mode pill ● LIVE (dark, dot, ~54 px) → PINNED (outlined, no dot, ~59 px) —
Time (mono) same 2:00 PM → 12:00 PM adds a character (~8 px)
Offset now (~22 px) → in 1 h / in 23 min (~40–55 px) in 1 h → in 11 h 30 → in 2 d 4 h
drawing… appears after every step while the map draws (~50 px), then disappears yes, twice per step
Live button appears right of › (~52 px with spacing) —

Live → Pinned grows the content left of ‹ by about 35 px and the content right of › by about 52 px. ‹ › move left by roughly (35 − 87/2) ≈ 8 px, and a filled Live button now starts 6 px right of ›. Then drawing… appears left of ‹ and pushes ‹ › right by about 25 px until the frame lands, then they jump back. A user who clicks › repeatedly is clicking a moving target, and the targets next to it, ‹ and Live, both undo the step. The centring, the content-sized text and the controls appearing between the pointer and the edge all add to the problem.

The dock has the same bug. In TimelineView.axaml:334–411 the step group is a right-aligned StackPanel. Go live appears inside it, right of ⏭, when the time is pinned, so ⏮ ‹ [step] › ⏭ jump about 80 px left on the first step. The step menu's label (StepLabel) also changes width with the step kind, which moves › and ⏭.

2.3 Other findings

# Finding Where
P1 One state, three ways. In Live the HUD reads ● LIVE, the time, then now; the stamp adds a fourth. Pinned reads PINNED, the offset and a Live button. The words carry the mode; the pill is redundant with them. HUD bar
P2 "Live" means two things. The dark LIVE pill is a status. The Live primary button is an action. The dock calls the same action Go live (TimelinePanel_GoLive). Next to PINNED, a button reading Live looks like a second status. TimeHud_Live vs TimelinePanel_GoLive
P3 "PINNED" is jargon and suggests a map pin (we already have route waypoints and pick markers). It's all caps, which reads as an alarm, but being pinned is a normal choice. TimelinePanel_Pinned
P4 Hierarchy. The pill, the 13 px semibold mono time and the accent-coloured offset all compete. In the pinned state the filled primary Live button is the loudest thing on the map, louder than the time. HUD bar
P5 Not theme-aware. The live pill is hard-coded #18181B with white text (dark-on-dark in the dark theme). The chip tints #D1FFFBEB/#D1FEF2F2 and the text #B45309/#B91C1C are light-theme only. The dock readout repeats the #18181B pill. TimeHudView.axaml:16–39, 50–55; TimelineView.axaml:20–26
P6 The dock toggle is cryptic. PanelBottom is a generic layout glyph with no label. In a narrow window it stays visible but disabled (CanExecute => !IsWindowNarrow), a dead button with no explanation. When the dock is open on another tab it switches tab, but the tooltip still says "Open timeline (T)". TimeHudView.axaml:181–189; MainViewModel.cs:1500–1509
P7 Discoverability of the step. ‹ › step "the next time sample", but the HUD doesn't say how far (hour, sample of which layer). The dock has a step menu; the HUD has nothing, so you only find out by stepping. Tooltip_TimelineNextStep
P8 Keyboard. ←/→/N/T work while the map, the Timeline or the HUD has focus (MainWindow.axaml.cs:1662–1692). But the only hint is the time's tooltip ("click, then ← → to step"), and a pointer user has no reason to click the time. Tab order inside the HUD is fine. Tooltip_TimeHudTime
P9 Accessibility. The bar has no group name. The mode is only in a pill with no automation name (the live pill has no AutomationId either). The offset isn't part of any accessible name, so a screen reader hears the time but not whether it's live. TimeHudView.axaml:118–150
P10 Display Not Real Time lives only in the stamp. While the HUD is the time surface, the S-98 indication is in a different corner from the control that caused it (the pin). §2.1

3. Decisions

One time surface at a time

D1. Exactly one time overlay on the map. The rule depends on whether the Timeline tab is on screen:

Timeline tab on screen? Map shows
No: dock closed, window < 900 px, or dock on Logs / Clearance Time HUD (controls)
Yes Map stamp (caption)

In code: IsMapStampVisible => Timeline.IsActive && IsBottomDockShown && IsTimelineTabSelected, which is the exact complement of IsTimeHudVisible while the timeline is active. That fixes complaint 1 and restores the #712/#713 intent.

D2. Display Not Real Time follows the surface, not the stamp. When IsNotRealTime is true, whichever surface is shown says so:

  • Stamp: unchanged (Display Not Real Time · time · offset).
  • HUD: the status slot (D5) reads NOT REAL TIME in the warning tone, instead of the plain pinned dot. The full phrase Display Not Real Time is the slot's tooltip and accessible name.

The HUD is in the Map capture region, so captures still carry it. IsMapStampVisible no longer ORs in IsNotRealTime.

D3. The two surfaces read the same, in the same order. Each one is a status dot, the time, then the offset. They differ only in role: the stamp is a caption (no controls, top left, small), the HUD is the control (bottom centre). The stamp drops the LIVE · prefix and uses the green dot plus a muted now, exactly as the HUD does (D5). Then the user reads one format everywhere, including the dock's readout.

A bar whose controls never move

D4. The HUD has a fixed geometry. The bar is a Grid with fixed column widths, not a content-sized StackPanel. Its total width therefore doesn't change with the mode, the time, the offset or drawing. Centring is harmless because there's nothing to re-centre. The width may change only when:

  • the map crosses a width class (compact < 640, tiny < 540, D10),
  • the time format or culture changes (Local ↔ UTC, a 12/24-hour locale), or
  • the dock toggle's availability changes (window crosses 900 px, D9).

None of these can happen during a click on ‹ or ›. As a belt and braces, the controls group is on the right of the bar and the variable text on the left, so even a future slot that misbehaves can't push the buttons from the pointer side.

Slots, left to right (regular class):

Slot Width Content
Status 14 px dot: green (Live), accent (pinned), grey pulsing (drawing), warning (not real time)
Time measured, see D6 CurrentTimeLabel, mono, left-aligned
Offset 84 px, left-aligned, ellipsis, full text in tooltip now (muted) · in 23 min · 5 h 37 ago · in 2 d 4 h
Separator 9 px —
‹ 28 px previous step
› 28 px next step
Live 64 px toggle, D5
Separator 9 px —
Dock 28 px D9

D5. Live becomes one fixed-size toggle; the mode pill goes. A single ToggleButton in a fixed 64 px slot, always present, replaces both the ● LIVE / PINNED pill and the Live button that appears and disappears:

  • Live: checked, quiet fill, green dot and Live. Clicking it again does nothing (it's already live). The tooltip says "Showing now and keeping up with it."
  • Pinned: unchecked, outlined, Go live (the dock's word, see P2). The tooltip is the current Tooltip_TimelineNow.

The left status dot and the muted now carry Live at a glance. The pinned state needs no word: the accent dot, the offset (in 23 min) and an unchecked Go live say it. That drops PINNED from the HUD (P1, P3). The button is never the primary (filled accent) style, so it no longer outshouts the time (P4).

D6. Stable text slots. The time slot's width is measured once per format from a template string with the widest digits and meridiem (12/28/2026 12:00 PM, or 28.12.2026 23:00, or 2026-12-28 23:00Z), and not from the live text. It's recomputed on TimeFormatChanged. The time keeps the mono face. The offset uses MonoFontFamily too (or FontFeatures="+tnum" if the UI font supports tabular figures), so in 1 h → in 11 h doesn't jitter. It's left-aligned so its start never moves.

D7. drawing… leaves the row. While the map draws, the status dot goes grey and pulses, and the time button's tooltip reads drawing 2:00 PM…. No text is inserted into the bar. If drawing takes longer than ~1 s, the existing message chip above the bar (F4, which grows upward and doesn't move the bar) shows Drawing 2:00 PM… · Cancel, using the existing CancelDrawingCommand.

D8. Step buttons keep their place at the ends of the range. At the first or last step ‹ / › are disabled, not hidden. (They aren't hidden today either; this pins it down as a rule.)

The dock toggle

D9. Say what the toggle does, and hide it when it can't. Keep the PanelBottom icon, but its tooltip and accessible name follow the state: Open timeline (T) with the dock closed, Show timeline (T) with the dock open on another tab. Below 900 px, where the dock can't show, hide it (the width change happens on a window resize, never under a click).

Narrow maps

D10. Narrow classes swap whole slots. compact (< 640 px) drops the offset slot. tiny (< 540 px) also shortens Go live to an icon-only toggle (28 px, Live glyph, same tooltip). Each class has fixed widths, so D4 holds within a class. There's no pinned label to drop any more (D5).

Theme, keyboard, accessibility

D11. Theme brushes only. The surface stays MapOverlaySurfaceBrush. The dot and toggle use SuccessColor, AccentBrush, MutedColor, and the warning/error tokens the rest of the viewer uses. Delete the hard-coded #18181B, #D1FFFBEB, #D1FEF2F2, #B45309 and #B91C1C (HUD and dock pill) in favour of theme resources, with dark variants defined next to MapOverlaySurfaceBrush in App.axaml.

D12. Name the parts. The bar gets AutomationProperties.Name "Time". The time button's name becomes the full reading, e.g. "2:00 PM, in 23 minutes, pinned" or "2:00 PM, live". The Live toggle exposes its toggle state. The status slot gets AutomationId="TimeHud.Status" (and the old TimeHud.PinnedPill id is retired; the preview packages allow clean breaks). The tooltips on ‹ › add the step and its key: "Next hour (→)", "Next sample of cbofs (→)", from the same StepLabel the dock uses (P7, P8).

The dock readout

D13. The dock's step group gets the same rule. In TimelineView.axaml, Go live becomes the same always-present toggle in a fixed slot, and the step menu button gets a MinWidth that fits its longest label (measured as in D6). Then ⏮ ‹ [step] › ⏭ stay put across Live/Pinned. The dock's mode pill follows D5 (dot plus offset, no PINNED word) so the dock, the HUD and the stamp read alike.

4. Mock-ups

The HUD, regular width. │ is a separator, [ ] a button; column positions are the same in every row.

Live
╭──────────────────────────────────────────────────────────────────────────╮
│ ●  10/31/2026  2:00 PM   now          │  ‹   ›  [● Live ]  │  ▭          │
╰──────────────────────────────────────────────────────────────────────────╯

Pinned, future (after pressing ›)
╭──────────────────────────────────────────────────────────────────────────╮
│ ●  10/31/2026  3:00 PM   in 1 h       │  ‹   ›  [Go live]  │  ▭          │
╰──────────────────────────────────────────────────────────────────────────╯

Pinned, past, while drawing (grey pulsing dot, nothing inserted)
╭──────────────────────────────────────────────────────────────────────────╮
│ ◌  10/31/2026  8:00 AM   5 h 37 ago   │  ‹   ›  [Go live]  │  ▭          │
╰──────────────────────────────────────────────────────────────────────────╯

Pinned with navigational warnings loaded (warning tone)
╭──────────────────────────────────────────────────────────────────────────╮
│ ▲ NOT REAL TIME  10/31  3:00 PM  in 1 h│  ‹   ›  [Go live]  │  ▭         │
╰──────────────────────────────────────────────────────────────────────────╯

For the not-real-time row, the time slot shortens to the date-less form so the total width is unchanged. Whether that's acceptable is open question Q2.

The message chip stays above the bar, centred, growing upward:

              ╭──────────────────────────────────────────╮
              │ No data for 2 of 5 layers    Next data › │
              ╰──────────────────────────────────────────╯
╭──────────────────────────────────────────────────────────────────────────╮
│ ●  10/31/2026  3:00 PM   in 1 h       │  ‹   ›  [Go live]  │  ▭          │
╰──────────────────────────────────────────────────────────────────────────╯

The map stamp (dock open on the Timeline tab only), top left:

╭──────────────────────────────╮
│ ●  10/31/2026 2:00 PM · now  │      Live
╰──────────────────────────────╯
╭──────────────────────────────────╮
│ ●  10/31/2026 3:00 PM · in 1 h   │  Pinned
╰──────────────────────────────────╯

5. Out of scope

  • A time picker in the HUD (F6 stays: clicking the time focuses the bar).
  • Backdrop blur behind the surfaces (#733).
  • Map- or data-area local time. Times are always the user's Local/UTC preference in the machine zone.
  • Putting charts and notices on the clock; Live stays the default.

6. Suggested slices

  1. One overlay at a time — D1, D2 (HUD side: the warning status slot), D3. MainViewModel visibility rules and StampText. Tests in MultiDockActivityTabTests for every row of §1.2, especially Logs and Clearance tabs and IsNotRealTime with the dock closed.
  2. Fixed HUD geometry — D4–D8, D10. Rewrite the bar as a fixed-column Grid with the Live toggle; move drawing… to the dot and the chip. A TimeHudViewTests case asserts that the screen bounds of TimeHud.Previous, TimeHud.Next and the Live toggle are identical across Live → step → drawing → step (in 1 h → in 11 h 30) → Go live, and across 12- and 24-hour cultures within one format.
  3. Dock readout — D13, with the same bounds test on Timeline.PreviousStep / Timeline.NextStep / Timeline.GoLive.
  4. Toggle, theme and accessibility polish — D9, D11, D12: dynamic dock tooltip and hiding, theme tokens for the pill and chip tints, automation names, step-aware tooltips. Update docs/ viewer pages and whats-new.md for the visible changes.

7. Settled questions

Settled 2026-10-31: the owner took the proposals.

  • Q1. The word for Pinned. It leaves the map surfaces (D5); the HUD and stamp carry the mode through the Live / Go live toggle and the offset. The word Pinned stays where it already is outside the map: the dock's accessible names, docs, and MCP's mode: "pinned". No rename.
  • Q2. Not real time in the HUD. Built (slice 2) as the second, fixed-height line: Display Not Real Time in full, in the warning tone, above the controls row, with the status dot in the warning colour. The HUD is anchored at the bottom, so the line grows the bar upward and never moves ‹ ›. This replaces the NOT REAL TIME slot with the date-less time from the mock-up: that version changed the time format on the first step, and the full phrase is the S-98 §12.7.2 wording.
  • Q3. Clicking Live while live. A no-op, so repeated clicks are safe.
  • Q4. Stamp with the Timeline tab shown. Kept: the dock's readout is far from the map, and captures of the Map region need the time.
  • Q5. Offset slot width. Fixed 84 px; longer gaps ellipsize with the full text in the tooltip (as in the D4 table). No per-culture measuring.
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