pyLogDigitizer

pyLogDigitizer turns inked paper scans (TIFF) and clean colour digital-print PDFs into LAS files, with a local browser app to check and fix every step. Nothing leaves your machine.

Overview

pyLogDigitizer converts two kinds of well-log print into LAS files: inked paper scans (TIFF) and clean colour digital-print PDFs, using shared scale, depth, null-value, and LAS export code. The scan workflow locates tracks and grids, reads depth labels, and traces curve ink; the digital-print workflow reads coloured vector paths directly, without rasterizing them or applying a scan model. Overlay QA draws grids and traces back onto the original print. A local browser editor supports review and correction before export, including curves that leave a track and return on a backup scale. All processing stays on your own machine; nothing is uploaded.

The package is under active development. Many functions are experimental and not fully validated; inspect overlays and exported curves before using the results.

Chitwood 12 paper log scan and the digitized LAS curve — The whole idea in one picture: a scanned paper log going in and a LAS curve coming out.

Examples

Tracing in the local browser app — The local browser app: a traced curve laid over the scan, with tools to pin, exclude and re-trace before you export.

Chitwood 12 QC vs KGS LAS — Chitwood 12 (KGS): digitized GR against the paired KGS LAS, with a depth plot and a cross-plot.

Chitwood 12 scan overlay — Chitwood 12 (KGS): traced GR and snapped grid lines drawn on the original scan, so you can check that the grid sits on the printed lines in every track.

Utah FORGE CBL original vs extracted grids and curves — Utah FORGE 78B-32 CBL: original colour print (left) → extracted grids and curves drawn back in contrasting colours (right).

Scan examples are from the Kansas Geological Survey. The colour digital-print example is the public Utah FORGE 78B-32 CBL (GDR / OpenEI).

Key features

Inked scan workflow

Detect tracks and grids, deskew scans, read depth labels, and separate curve ink with a bundled ONNX segmenter before tracing with a Rust engine or Python fallback.

Colour digital-print PDFs

Extract coloured vector paths directly, identify per-track grids and scales, and digitize curves without rasterizing the PDF or using the scan model.

Overlay quality checks

Draw snapped grid lines and traced curves on the original scan or rendered PDF page to check alignment by eye.

Local browser editor

Pin and drag anchors, exclude regions, re-trace curves, adjust track edges and scales, and correct header text before export.

Backup scales and nulls

Unwrap curves that run off a track onto a backup scale; handle log scales and null values where a fixed-scale curve is clipped.

LAS 2.0 export

Write depth-calibrated LAS 2.0 curves at 0.5 ft spacing by default, with 0.25 ft spacing available.

Installation

pip install pylogdigitizer

Requires Python 3.10 or newer. Review the README for the scan and digital-print PDF workflows.

Citation

Lai, L.S.-H. (2026) pyLogDigitizer. Zenodo, https://doi.org/10.5281/zenodo.23832013

pyLogDigitizer is under the GNU Affero General Public License 3.0 or later.

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