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Advanced Editing Settings

The Advanced Editing settings category controls Mapit's Pro+ power-user editing tools. It covers three tools: Split (cut a feature into two), Buffer (generate a polygon buffer around a feature), and Merge (combine two adjacent features into one).

See the workflow articles for context: Split Operation, Buffer Tool, and Merge Tool.

Go to Settings > Advanced Editing to access these options.

Pro+ feature

Advanced Editing requires a Mapit Pro Plus subscription. The master toggle is visible on all tiers, but turning it on without Pro+ opens the subscription paywall.

Enable Advanced Editing​

Default: Off

The master switch for the Advanced Editing tools. When off, the Tools chip on the edit toolbar does not appear, and the Advanced editing tools section in the edit-coordinates dialog (for points) is hidden. Free / Pro / Pro+ users all see the same toolbar in this case - byte identical.

When on (Pro+ only), the Tools chip appears whenever you open an existing polygon or polyline feature for editing, and the dialog section appears for point features. Both surfaces lead into the editing-tools bottom sheet.

The other settings on this screen apply only when this master toggle is on. They keep their last values when the master is flipped off, so you can re-enable Advanced Editing without reconfiguring them.

Split tool​

Settings under the Split tool category header configure the Split Operation.

Largest piece keeps original attributes​

Default: On | Visible when: master is on

After a successful split, two pieces are produced. One keeps the original feature's row ID and attributes; the other becomes a new feature.

  • On (default) - the larger piece is treated as the original. The smaller piece becomes the new feature. You can still tap the smaller piece on the map to swap before confirming.
  • Off - the polygonize-output order is used as the default (essentially arbitrary). You almost always want to swap manually in this case.

The map preview after Apply colours the chosen "original" piece green and the "new feature" piece blue.

Wipe attributes on new feature​

Default: Off | Visible when: master is on

Controls the attribute payload of the freshly-inserted second piece:

  • Off (default) - all attributes from the original feature are copied verbatim onto the new row. The two rows now have the same attribute values, just different geometries. Useful when both halves are still "the same parcel" attribute-wise (e.g. cadastral split where both halves keep the owner attribute).
  • On - the new row is inserted with blank attributes. You fill them in afterwards. Useful when the two halves are conceptually different features (e.g. forestry stands where the split represents a change of management unit).

The original row's attributes are never modified, only its geometry.

Interpolate Z values along cut line​

Default: On | Visible when: master is on

Only relevant for Z-capable polygons (3D vertices). When on, vertices created along the cut line inherit Z values via linear interpolation between the two outer-ring crossing points. When off, cut-line vertices get Z = 0.

Most surveying use cases want this on for topological consistency with the source's elevations.

Buffer tool​

Settings under the Buffer tool category header configure the Buffer Tool.

Buffer shape​

Default: Filled | Visible when: master is on

ValueBehaviour
Filled (full polygon)Standard buffer polygon - source plus a margin of the chosen radius.
Ring (donut around the original)The buffer polygon minus the source polygon. Just the band of area within N metres of the boundary. Polygon source + positive radius only; the slider hides negative values when this is selected.

For point sources, shape is forced to Filled regardless of this setting (a ring around a single point is geometrically degenerate without an inner radius too).

Corner style​

Default: Round | Visible when: master is on

Maps directly to JTS' join-style parameter:

ValueBehaviour
Round (smooth)Curved corners. Standard buffer look.
Mitre (sharp)Sharp corners that extend the source's edges to a point. CAD-feel for cadastral / regular shapes (buildings, parcels).
Bevel (clipped)Clipped sharp corner - the offset edges meet via a flat segment.

The default is Round; surveyor work usually wants smooth corners. Architects and CAD users tend to prefer Mitre.

Line end caps​

Default: Round | Visible when: master is on

Only relevant when buffering polylines. Maps to JTS' end-cap-style:

ValueBehaviour
RoundRounded semi-circular caps at each line end. Standard.
FlatThe buffer clips flat at the line endpoint. Useful for road centerlines buffered into a carriageway, where rounded ends look out of place.
SquareThe buffer extends past the line end by the radius distance, with a square cap.

Allow negative radius (shrink polygons)​

Default: Off | Visible when: master is on

When on, the buffer slider exposes negative values. A negative radius shrinks a polygon inwards by that distance. Useful for stand-off zones inside a parcel ("everything more than 5 m from the boundary").

The slider gating is conservative on purpose - negative values are only shown when all of the following hold:

  • This setting is on.
  • The source is a polygon (negative radius is undefined for points and lines).
  • The buffer shape is Filled (a shrunk ring would always be empty).

In every other combination the slider stays at the positive-only 1 to 500 m range so you are not offered values that would just be rejected.

Merge tool​

Settings under the Merge tool category header configure the Merge Tool.

Largest piece keeps original attributes​

Default: On | Visible when: master is on

When you confirm a merge, one row keeps its ID and attributes; the other row is deleted. This setting controls which side starts as the kept row when the preview opens.

  • On (default) - the larger piece (by area for polygons, by length for polylines) is preselected as the kept side. The smaller-side row is deleted on Apply unless you swap. Most surveying workflows want this on.
  • Off - the first feature (the one you started the edit session on, labelled A on the map) is preselected as the kept side regardless of size. Useful when your "starting point" is always the one you care about.

In either case, the preview card has two pills (A / B) and you can tap to swap before confirming. The kept side's label on the map renders larger with a thicker purple halo so the choice is visible at a glance.

The kept row always retains its own attribute values; the deleted row's attributes go with it.