Vectorize scanned maps in one tool — Extract Scanned Lines and Polygons in ArcGIS Pro 3.7
Every long-lived GIS shop has the same skeleton in the closet: a drawer (or a network share) full of scanned maps that never became data. Utility as-builts, old parcel books, soil surveys, hand-drawn contour sheets — georeferenced at best, traced by hand at worst. ArcGIS Pro 3.7 finally ships purpose-built geoprocessing for this: Extract Scanned Lines and Extract Scanned Polygons, two new tools that read the linework off a scanned image and hand back clean vector features.
Released in the May 2026 update, both tools live in the Conversion toolbox, in the From Raster toolset. If you remember ArcScan from the ArcMap era, this is the idea reborn as modern, scriptable geoprocessing — no extension, no raster-cleanup editing session, no separate toolbar. Here is what the tools actually do, the parameters that decide whether your output is usable, and the two catches (input format and licensing) to know before you plan a conversion project around them.
What the two tools do
Both tools take a scanned map image that has been classified into exactly two classes — foreground linework and background — and convert the foreground cells to features:
- Extract Scanned Lines generates polyline features at the centerlines of the raster linework — the right output for contours, utility lines, parcel boundaries, streams, and anything drawn as a stroke.
- Extract Scanned Polygons generates polygon features along the outlines of the foreground cells — the right output for filled areas like land-use patches, building footprints, or shaded zones.
Extract Scanned Lines can even do both jobs at once: its optional Output Polygon Features parameter catches anything wider than your Maximum Line Width and writes it out as polygons, so a sheet that mixes thin linework with filled symbols doesn’t need two passes.
The workflow this replaces
Until now, Esri’s own recommended path for this problem was a relay race across toolboxes. The support knowledge base (Article 000034497) walks through it: georeference the scan, run Reclassify (Spatial Analyst license) to isolate the linework, run Raster to Polyline, then patch the result with Snap, Simplify Line, and Smooth Line, and finally Merge or Dissolve the pieces together.
That chain works, but it treats the symptoms one tool at a time — and none of those tools understand that the raster is scanned linework. Raster to Polyline has no concept of a line intersection, a scanning gap, or a corner; you fix those artifacts downstream, feature by feature. The new tools bake that understanding into the extraction itself, which is exactly where it belongs.
The parameters that decide your output quality
Intersection Solution — the one to get right first
Where three or more raster lines meet, the tool has to decide what geometry to build. Extract Scanned Lines gives you three strategies, and Esri’s documentation is unusually concrete about when to use each:
| Option | What it does | Use it for |
|---|---|---|
| Geometrical (default) | Preserves angles and straight lines at intersections | Site plans, engineering drawings — anywhere angular accuracy is critical |
| Median | Averages directions where lines meet at irregular angles | Natural and organic features — environmental mapping, streams, soil lines |
| None | No special handling; extracts as-is | Data with no meaningful intersections — elevation contours |
Cleanup built into the extraction
The rest of the parameter list reads like a checklist of everything that used to go wrong in the old multi-tool chain:
- Noise Level omits speckle and stray pixels from the extraction — the scanning dust you used to clean up in an image editor first.
- Close Gaps, with a Gap Tolerance (in pixels) and a Gap Search Angle, bridges breaks in a raster line so a faded or interrupted stroke still comes out as one continuous polyline. The search angle matters on curved lines — it keeps the tool following the arc instead of jumping to the wrong neighbor.
- Hole Size absorbs small enclosed gaps inside a line (classic scanning-error artifacts) so they don’t punch through the extracted feature.
- Resolve Corners with a Maximum Corner Angle sharpens corners where linework intersects — worth enabling for built-environment sheets, and skipping for natural features where a rounded corner is truer to the source.
- Compression Tolerance and Apply Smoothing/Smoothing Weight control generalization: fewer vertices and smoother strokes, traded against deviation from the original shape. These replace the separate Simplify Line and Smooth Line passes.
- Maximum Line Width is the sorting hat: anything at or under the width is centerline material, anything wider is polygon material. Measure it off your actual scan — the docs flag that this value also influences how output features are constructed, so a sloppy guess degrades everything.
A practical first run
- Georeference the scan first. The extraction inherits the raster’s coordinates; vectorizing an unreferenced image gives you beautifully clean features in the wrong universe.
- Make it binary. Both tools require the raster classified into exactly two classes. A Reclassify pass (or any classification that yields foreground vs. background) gets you there; note the foreground value.
- Run Extract Scanned Lines with defaults on a representative subsection — set only the input, foreground value, output, and an Intersection Solution chosen from the table above.
- Iterate on the cleanup parameters where the output disappoints: gaps in faded lines → Close Gaps; speckle features → Noise Level; jagged strokes → smoothing; blobby wide symbols → Maximum Line Width + Output Polygon Features.
- QA with topology rules (dangles, self-intersections) before the data goes anywhere near production — automated extraction is a head start, not a substitute for validation.
Because both tools are standard geoprocessing in the Conversion toolbox, they are fully scriptable
— arcpy.conversion.ExtractScannedLines and
arcpy.conversion.ExtractScannedPolygons — so a drawer of two hundred sheets
becomes a batch job over a folder of georeferenced, binarized rasters rather than two hundred editing
sessions. That is the real payoff: the tools turn map modernization from an editing project into a
pipeline.
The two catches
Where this pays off
The organizations that should care most are the ones sitting on paper-era records with modern-data obligations: utilities with scanned as-builts feeding a network migration, counties with parcel books that predate their geodatabase, environmental agencies with decades of hand-drawn survey sheets. For those archives, the difference between “a digitizing tech traces sheets for a year” and “a parameterized batch pipeline with human QA” is the difference between a project that gets funded and one that doesn’t.
References
- What’s new in ArcGIS Pro 3.7 — ArcGIS Pro documentation (Extract scanned lines and polygons highlight)
- Extract Scanned Lines (Conversion Tools) — tool reference (parameters, usage notes, licensing)
- Extract Scanned Polygons (Conversion Tools) — tool reference
- Extract lines from a scanned map to a feature class — Esri Support (Article 000034497) (the pre-3.7 multi-tool workflow)
Sitting on a drawer of scanned maps?
We build scan-to-vector pipelines — georeferencing, extraction parameter tuning, batch automation with ArcPy, and topology-driven QA — so your paper archive becomes production data, not a year of tracing.
Book a free intro call