Markup and redlining

Markup is the fastest way to get team feedback on a map. Anyone who can view the map can draw on it, group sketches into named markup sets, and ship the link back to the team. No editor permission needed.

Signed-in viewers can always add their own markup. Map editors can also turn on Anonymous markup in Map settings so signed-out visitors on a public map can add and edit their own sets (off by default, rate-limited). Guests cannot promote a set to a data layer — that still needs a signed-in account.

When two signed-in people edit the same markup set at once, the portal merges their sketches live (see Live presence). Anonymous markup does not use that path.

The classic use case: a project manager opens a shared parcel map, spots three parcels with wrong boundaries, sketches the correct edges, and emails the map URL to the analyst who can fix the underlying data. The analyst sees the manager's markup overlaid on the map next to their own work and knows exactly which features to look at.

Opening the Markup panel

In the map editor toolbar, click the pencil icon. The Markup panel slides in from the right.

Adding markup

Click Add markup. A new markup set appears, named after you and today's date, with an auto-assigned color so two reviewers' markups don't clash. Each set is its own overlay of features.

Use the tools on a set, then click the map to draw:

• Pin: single click.
• Line: click vertices; double-click or press Enter to finish.
• Polygon: click vertices; double-click or Enter to close.
• Text: click to place, then type the label when prompted.
• Arrow: same as a line; the tip gets a chevron so direction is obvious.
• Circle: click the center, then drag to set the radius (stored as a polygon outline).

Center still drops a pin at the current map center when you just need a quick marker without switching tools.

Download as GeoJSON

Click GeoJSON on any markup set that has features. Your browser downloads a FeatureCollection with every pin, line, polygon, text, arrow, and circle in that set. Properties include kind, label, note, color, and which markup set / author they came from. Opens directly in QGIS, ArcGIS Pro, geojson.io, and similar tools. Anyone who can see the set can download it — no edit permission required.

Promote to a data layer

When a markup set is ready to become real GIS data, click Promote. GratisGIS creates a private data layer you own, copies every feature into it (splitting points, lines, and polygons into separate sublayers when the set is mixed), and, if you can edit the map, adds that layer to the map for you. The original markup stays in place so the review trail is not lost.

Multiple reviewers, distinct colors

When several people add markup to the same map, each person's set gets its own color from a built-in palette. The colors are picked so two adjacent ones never look the same, including for common forms of color blindness.

You can rename your set (click the title), recolor it (click a swatch), or hide it temporarily (eye icon). Hiding only affects your own view; the set is still there for everyone else.

Who can edit which markup

• The author of a markup set can edit or delete it at any time.
• A map editor (someone with edit permission on the map item) can edit or delete any markup set on that map. This is the cleanup path: an admin can remove abandoned markup from a long-running shared map without asking the author.
• Other viewers can see all markup sets but can only edit or delete their own.
• Anonymous guests (when the setting is on) edit only sets they created in the same browser; clearing site cookies loses that edit right, though the markup stays on the map.

Tips

• Drawings persist on the map item. A new visitor sees every set that's been added so far.
• A markup set isn't a data layer until you promote it. Download GeoJSON when you just need the sketches offline; promote when you want styling, sharing, OGC access, or derived-layer pipelines on the result.
• Comments threaded against the map and against individual pins pair nicely with markup. See Comments for the conversation side.