Annotating on the map: showing the extent, not just the spot
Add zones, lines and photo points to a task's map so people see the size of the job before they head out.
A task pin says "there's a problem here". It doesn't say whether that's three metres or three hundred.
Map annotations answer that. On a task's map you can draw the flooded area, trace the reroute to open, drop a point on the stump to pull and attach two photos to it. Whoever picks up the task sees the size of the job before leaving — and loads the right gear.
Where: on a task's form — the Annotate on the map button on the web, the Annotate chip on mobile.
Where to find it
Annotations live on a task, both when creating and when editing, on web and on mobile.
The button, on the form's map preview.
- 1The button sits over the map preview, top left.
On the web, the Annotate on map button sits on the map preview of the task form. On mobile, it's the Annotate chip at the top right of the task's map header — with a counter as soon as there are annotations.
Two limits to know:
- The task must have a position. A to-do, which has none, has no annotations.
- Annotations belong to tasks. Structures and inspection reports don't have them.
Three tools
Whatever the device, it's the same three shapes.
| Tool | What it is | What it gives you |
|---|---|---|
| Zone | A closed polygon, 3 corners minimum | Its area, in m² |
| Line | An open path, 2 points minimum | Its length, in metres, plus an adjustable width |
| Point | A pin dropped at a precise spot | A photo holder: the only shape that takes images |
Those measurements aren't decoration: a 1,240 m² zone is a figure that goes into a grant application.
The point is the most useful of the three. It's the only one that carries photos, and that's what turns a task into a file: the photo of the stump is attached to the stump, not lost in a pile of uncaptioned images.
The dialog, on the web
The annotation dialog.
- 1The tools: select, zone, line, point.
- 2The layer list, with the eye to hide and the bin to delete.
- 3The properties of the selected annotation.
Pick a tool, then click the map to draw. Double-click to finish a zone or a line. Go back to the select tool to rework a shape: its corners become draggable, and the midpoints let you insert new ones.
The right column is the layer list. It holds your annotations, but also the task's own point or segment — which you can hide with one eye while you draw over it. Hiding erases nothing: it's a working convenience.
Below the list are the properties of the selected annotation:
- its name — with no name it's "Zone 1", "Line 2"; with a name it actually says something;
- its colour;
- for a line, its width, from 1 to 12 pixels;
- for a point, its photos.
Nothing is stored until you click Confirm — and then save the task. That's what trips people up most: confirming the dialog only brings the annotations back into the form.
In the field
Annotating on mobile.
- 1Close on the left, confirm on the right.
- 2The hint tells you what to do with the current tool.
- 3The four tools, including the photo survey.
Mobile takes the whole screen: the map goes full screen and the controls live in a dark bar at the bottom. You tap the map to place corners, and Finish closes the shape.
Three things mobile can do that the web can't:
Follow GPS. On a line, instead of drawing it with your finger, tap Follow GPS and walk the path. The button only shows while you haven't placed a point yet: you pick one method or the other at the start. The phone records your track and smooths it — points that are too imprecise, too close together or too fast are dropped. That's the right way to survey a real reroute, the one that actually gets around the obstacle.
Use my current position. On a point, this button drops it where you stand. You're in front of the stump: one tap and it's mapped.
The photo survey, the fourth tool — the rest of this page.
To rework an annotation, tap it: its corners appear, a handle at the centre moves the whole shape, and the midpoints insert new corners. The bottom bar then turns into an editor: name, six colours, a swatch for a free colour, width for a line, photos for a point.
On the way out the app asks you to keep your changes. Same story: keeping brings them back into the form, you still have to save the task to apply them.
The photo survey
The photo survey.
- 1The current GPS accuracy — green under 10 m.
- 2Merging photos taken in the same place.
The photo survey turns the logic around: instead of dropping a point and then adding a photo to it, you take the photo, and the point places itself where you shot it.
It's the walk-the-trail tool. You head down the trail, photograph what's wrong, and come back with a series of geolocated points — without having touched a map once.
Two details that matter:
The accuracy chip at the top right shows the GPS margin of error: green under 10 m, orange up to 25 m, red beyond. Under dense canopy, wait for it to settle before shooting — otherwise your points will be off.
Merging. Turned on, two photos taken less than eight metres apart land on the same point. That's what you want to photograph one problem from three angles. Turn it off if you're documenting distinct things that happen to be close together.
What everyone else sees
Once the task is saved, the annotations show on its map in both apps. They also follow the task beyond Sentinel:
- on a public share link, the public map shows the annotations;
- the GPX, KML and GeoJSON exports carry them, ready to open in mapping software.
That's what makes the effort pay: the drawing done once serves the person doing the work, then the report, then the funder.
Three pieces of advice
Name what you draw. "Zone 1" tells nobody anything. "Flooded section at thaw" still makes sense six months later.
One colour per kind of problem. Red for what blocks, orange for what needs watching, green for the shape of the fix. The code doesn't need to be written down: it becomes obvious after three tasks.
Walk your lines rather than drawing them. A reroute traced with a finger over satellite imagery often runs through a bank. The same survey done on GPS is accurate to the metre.