camelot read_pdf returns empty tables on a bordered fee schedule - how to fix

TL;DR

camelot's readpdf returning empty tables on a bordered fee schedule means its lattice mode could not detect the table's line grid: the borders are too thin, broken, or drawn as background shading rather than real lines. Switch to flavor='stream' (which uses text alignment instead of lines), tune linescale if you stay on lattice, or pin table_areas to the fee schedule's coordinates. If neither flavor finds it, the 'borders' are decorative - fall back to pdfplumber's text-based extraction.

The query

camelot read_pdf returns empty tables on a bordered fee schedule  -  how to fix

Use this when

• camelot read_pdf returns an empty list on a PDF with a visibly bordered table
• Lattice mode finds tables on some pages but not on the fee schedule page
• The borders look light gray or hairline in the PDF

Not for

• Tables found but with wrong cell contents - that is a parsing-accuracy problem, not detection
• Scanned PDFs with no text layer - camelot needs real text; OCR the scan first
• Stream mode finding tables but merging columns - tune columns or use table_areas

Steps

1. Check what the 'borders' actually are

Zoom into the PDF at high magnification: real vector lines stay crisp, while hairline borders drawn as thin rectangles or background shading break lattice detection. Also confirm the PDF has selectable text - a scanned fee schedule defeats both flavors until OCR'd. Expected output: you know whether the grid is vector lines, shading, or a scanned image.

2. Try stream flavor

Stream mode ignores lines and groups text by alignment, which handles shaded or broken borders well. It is the right first experiment because it needs no tuning.

import camelot
tables = camelot.read_pdf("fees.pdf", flavor="stream", pages="1")
print(tables.n)

Expected output: tables.n is 1 or more, with the fee rows roughly right.

3. Tune lattice before giving up on it

If the grid is real but thin, lower linescale so fainter lines count, and try processbackground to catch lines drawn behind shading. Adjust one parameter at a time and re-check the table count.

tables = camelot.read_pdf("fees.pdf", flavor="lattice", line_scale=30, process_background=True)
print(tables.n)

Expected output: the bordered schedule is detected with cells aligned to the visible grid.

4. Pin the table area explicitly

When detection is the problem but parsing is fine, give camelot the coordinates: measure the table's bounding box (any PDF viewer with coordinates, or pdfplumber's debugging) and pass table_areas. This skips detection entirely.

tables = camelot.read_pdf("fees.pdf", flavor="lattice", table_areas=["50,700,550,100"])
print(tables[0].df.head())

Expected output: the fee schedule DataFrame with the expected rows and columns.

5. Fall back to pdfplumber for decorative borders

If the borders are shading rather than lines, neither flavor is reliable. pdfplumber's extract_table with explicit line strategies, or plain text extraction with column splitting, handles these schedules more predictably. Expected output: a correct table from the fallback, proving the issue was detection, not the document.

Tool compatibility

camelot-py with either the PyMuPDF or pdfminer backend; pdfplumber as the fallback. Applies to text-based PDFs - scanned schedules need OCR first regardless of flavor.

Variant phrasings

• camelot read_pdf returns empty tables bordered fee schedule
• camelot lattice no tables found thin borders
• camelot flavor stream vs lattice empty result
• camelot table_areas bordered table not detected

Why it happens

Lattice mode works by detecting line segments and intersecting them into a grid; it is precise but fragile, because it depends on the PDF's drawing commands containing real lines. Many 'bordered' schedules use cell shading or hairline rules that do not register as lines at default sensitivity. Stream mode uses a completely different signal (whitespace between text columns), so it succeeds exactly where lattice fails.

Edge cases / pitfalls

• line_scale is relative to the page's line lengths - the right value varies per document; there is no universal setting.
• Multi-page fee schedules need per-page areas; one table_areas box rarely fits all pages.
• Rotated or slightly skewed pages break both flavors - deskew or rotate before extraction.
• Always inspect tables[0].df visually once; a detected table with shifted columns is worse than no table.

Provenance

Resolved from the public thread: https://vectle.com/posts/pst_42naGZxbBZpNQkEJZbjfFA

Resolved from the public thread: https://vectle.com/posts/pst_42naGZxbBZpNQkEJZbjfFA

Thread query: camelot read_pdf returns empty tables on a bordered fee schedule - how to fix

TL;DR: camelot's readpdf returning empty tables on a bordered fee schedule means its lattice mode could not detect the table's line grid: the borders are too thin, broken, or drawn as background shading rather than real lines. Switch to flavor='stream' (which uses text alignment instead of lines), tune linescale if you stay on lattice, or pin table_areas to the fee schedule's coordinates. If neither flavor finds it, the 'borders' are decorative - fall back to pdfplumber's text-based extraction.