Feature Editor

What Is a Feature Editor?

A feature editor is an interactive tool for modifying the geometry and attributes of GIS vector features directly in the map view. Rather than writing code or exporting to a desktop GIS, you click, drag, and reshape features right in your browser. The Feature Editor on gis.tools supports moving entire features, rotating them, scaling them, editing individual vertices, and adjusting attributes — all the core operations you'd expect from a digitizing session in QGIS or ArcMap, packaged as a zero-install web app.

Feature editing is one of the most common GIS tasks: cleaning up auto-generated footprints, correcting misaligned parcels, refining buffered zones, or tweaking a drawn route. Desktop GIS solutions make this easy but require setup; web map digitizers like iD or GeoMan are feature-rich but tied to specific datasets. Our Feature Editor sits in between — it accepts any GeoJSON, KML, or Shapefile, presents an editable map, and exports the edited result back to the same format. All editing is done client-side with an undo/redo stack that captures every atomic operation.

The tool is particularly useful for last-mile data cleanup: a field crew returns with a GPS track that needs a few corrections; a municipal engineer receives a contractor's deliverable that has a few misaligned vertices; a planner needs to nudge a zoning boundary to match a new aerial photo. Any of these become a five-minute fix in the browser rather than a thirty-minute desktop session.

How Feature Editing Works

Transform Handles

Selecting a feature enables transform handles — markers at the corners and edges of the feature's bounding box. Dragging a corner scales the feature; dragging an edge moves it; a rotation handle above the top edge allows rotation around the centroid. Each transform is applied uniformly to all vertices and is committed as a single undo step.

Vertex Editing

Clicking inside a selected feature drops into vertex mode. Individual vertices can be dragged, added (by clicking on an edge), or deleted (by selecting and pressing Delete). This is the level at which topology errors are fixed manually.

Attribute Editing

A side panel shows the feature's properties table, where values can be edited in place. Attribute changes are also undoable.

Snapping

Optional snapping to nearby features, vertices, or midpoints helps align edits with existing geometry. Snap tolerance is configurable in pixels.

Key Parameters and Options

Selection Mode

Single-click selects one feature; shift-click adds to selection; rectangle drag selects all features within a box.

Snap Tolerance

Distance in pixels within which the cursor snaps to existing features. Typical values are 5-15 pixels.

Transform Mode

Move, rotate, scale, or skew. Most editing uses move/rotate/scale.

CRS

The tool respects the CRS of the input file. For precise meter-based edits, import data already projected in UTM or a local grid via the EPSG Reprojector & Coordinate Converter.

Practical Applications

Parcel and Cadastre Cleanup

Municipal parcel layers often have small alignment errors from historical digitization. Editors can nudge corners into place against an aerial photo basemap, resolving disputes without a full re-survey.

Building Footprint Refinement

Machine-learning-derived building footprints (from Microsoft, Google, Overture Maps) are often close but imperfect. Manual refinement of edges and corners is still the fastest way to achieve survey-quality footprints.

Field Data Correction

GPS tracks from field crews drift, especially under tree cover. Manual vertex editing straightens obvious errors before the data becomes canonical.

Route Planning and Review

A proposed route (transmission line, pipeline, bike path) often needs tweaking between design iterations. Editing in the browser avoids the round-trip to the design team's desktop GIS.

Map Digitizing from Scans

Heads-up digitizing on a georeferenced aerial or scanned map is a classic GIS workflow. The editor supports this with snap and undo.

Data Cleanup Before Publication

Before a dataset goes into a public catalog, a final manual pass to fix obvious errors is often worthwhile. The editor makes this last-mile cleanup painless.

Collaborative Edits

Analysts can share a GeoJSON, each perform some edits, and merge the results back together. Because everything runs locally, there's no central server to synchronize.

Step-by-Step Workflow in gis.tools

1. Open the Feature Editor in your browser.
2. Drop a GeoJSON, KML, or Shapefile into the map. The features appear as editable layers.
3. Click a feature to select it. Transform handles appear around it.
4. Use the transform handles to move, rotate, or scale, or double-click to enter vertex edit mode.
5. Make your changes. The Undo/Redo Edit Stack captures every step.
6. Edit attributes in the side panel.
7. Export the edited layer as GeoJSON, Shapefile, or KML.

Worked Example

A municipal GIS technician receives a shapefile of new building footprints from a drone contractor. Overlaying the layer on current aerial imagery reveals that 23 footprints are rotated slightly because of a coordinate calibration error. She loads the shapefile into the Feature Editor, selects each misaligned footprint in turn, uses the rotation handle to align it with the aerial photo, and exports the corrected layer. Total time: under 15 minutes. No desktop GIS was needed and no data left her laptop.

Common Pitfalls and Gotchas

• Lost edits on tab close: Browser editing state is ephemeral; export frequently.
• Snapping to the wrong layer: Snap tolerance applies to all visible layers; disable non-target layers to avoid cross-layer snapping.
• Topology breakage: Editing one polygon can leave gaps or overlaps with neighbors. Run Topology Helpers afterward.
• Attribute loss: Some export formats (older shapefile) truncate field names to 10 characters.
• Projection drift: Editing in geographic degrees gives asymmetric scaling at high latitudes. Reproject to UTM for precise meter-based edits.
• Very small features: Hard to select at low zoom; zoom in before editing.
• Rotated features: The rotation handle rotates around the centroid; for rotation around a different pivot use multiple move operations.
• Invalid geometry after edit: Manual vertex edits can introduce self-intersections; run Geometry Repair if in doubt.

Tips for Best Results

• Export an intermediate copy every few minutes. Browser tabs can crash.
• Use snapping aggressively to maintain topology.
• Zoom in before editing small features.
• Reproject to a meter-based CRS for precise edits.
• Keep the source file unchanged; work on a copy.
• Use undo liberally — it's there for a reason.
• Run validation after complex edit sessions via the GeoJSON Validator & Fixer.
• For very complex edits, switch to a desktop GIS after exporting.

Comparison with Other GIS Approaches

QGIS's digitizing toolbar and ArcGIS Pro's editor are the desktop reference — deeper feature sets, stronger topology tools, and better for long sessions. Web editors like iD (OpenStreetMap), Mapbox Studio, and GeoMan are similar in spirit but tied to specific datasets or platforms. Our Feature Editor is the lightweight, format-agnostic option for quick, private edits.

Performance Considerations

Interactive editing scales to layers of a few thousand features comfortably. Beyond that, the map renderer slows and vertex selection becomes imprecise. For larger layers, split into tiles and edit each tile separately.

Data Privacy and Browser-Based Processing

All editing is local. Parcel data, sensitive infrastructure footprints, and confidential research geometry never leave your browser. Close the tab and the data is gone.

Related GIS Concepts

• Digitizing: creating vector features by clicking on a basemap or imagery.
• Snapping: automatically aligning edits to nearby vertices or edges.
• Topology: the relationships between features (shared boundaries, containment).
• Dangling nodes: unconnected line endpoints that should touch another line.
• Undo/redo stack: the history of edits used to reverse or replay operations.

Frequently Asked Questions

Can I edit shapefiles?

Yes — drop a .zip of the shapefile and edit as you would a GeoJSON. Export keeps the format.

Does it preserve attributes?

Yes — attributes are editable in the side panel and exported along with the geometry.

Is there undo?

Yes — see the Undo/Redo Edit Stack tool. Every atomic edit is undoable.

Can I edit multiple features at once?

Yes — shift-click or rectangle-drag to multi-select, then apply transforms to all.

What happens if I close the tab?

Edits are lost. Export before closing.

Related Tools on gis.tools

• Draw Points/Lines/Polygons
• Topology Helpers
• Geometry Repair
• Undo/Redo Edit Stack
• Cut Polygon by Line
• Merge Features
• GeoJSON Validator & Fixer
• Simplify Preserving Topology