Frame

A Frame wraps one FRAME EFLR object plus all the FDATA IFLR records that belong to it. Each frame defines one continuous depth (or time) track and the set of channels recorded along it.

Properties

Frame.key

OBNAME triplet string "origin/copy/name" that uniquely identifies this frame within the logical file.

Type:: string

Frame.name

The frame name as stored in the FRAME EFLR OBNAME.

Type:: string

Frame.description

Optional free-text description from the DESCRIPTION attribute.

Type:: string

Frame.indexType

The type of the index channel — typically "BOREHOLE-DEPTH", "TIME", or "VERTICAL-DEPTH". May be an empty string if the attribute is absent.

Type:: string

Frame.direction

Recording direction of the index channel: "INCREASING" (tool going down / time advancing) or "DECREASING" (tool pulled up).

Type:: string

Frame.spacing

Nominal step between consecutive index values (depth increment or sampling interval). null when not specified.

Type:: number | null

Frame.channelNames

Channel names in recording order (first channel is the index channel).

Type:: string[]

Frame.channels

Fully resolved ChannelInfo objects in recording order. Channels not found in the registry are omitted.

Type:: ChannelInfo[]

Methods

Frame.decode()

Decode all FDATA IFLR records belonging to this frame into typed arrays.

Returns:: A DecodeResult object, or null if there are no FDATA records for this frame.
Return type:: DecodeResult | null

const result = frame.decode();
if (!result) { console.log('no data'); return; }

console.log(result.frameCount, 'rows');

// Scalar channel
const depth = result.data['DEPTH'];   // Float64Array, length = frameCount

// Array channel  (e.g. waveform with 500 samples per row)
const stride = result.strides['VDL']; // 500
const vdl    = result.data['VDL'];    // Float64Array, length = frameCount * 500
const row0   = vdl.slice(0, stride);  // first waveform

Note

All numeric values are promoted to Float64Array regardless of the original representation code. Signed 16-bit waveform samples (RC.SNORM) are faithfully preserved in the double buffer.

Frame.toCSV([opts])

Export all scalar channels to a CSV string (one row per depth sample, header row with channel names).

Arguments:

opts (object) – Optional export options.
opts.channels (string[]) – Subset of channel names to include. Defaults to all scalar channels.
opts.nullStr (string) – String to emit for null/absent values. Defaults to ''.

Returns:

CSV-formatted string.

Return type:

string

// All scalar channels
const csv = frame.toCSV();

// Only specific channels, NaN shown as '-9999.25'
const csv2 = frame.toCSV({ channels: ['DEPTH','GR','CALI'], nullStr: '-9999.25' });

// Save (Node.js)
import { writeFileSync } from 'fs';
writeFileSync('well.csv', csv);

Frame.toLAS([opts])

Export all scalar channels to a LAS 2.0 string. The ~WELL section is populated from LogicalFile.origin.

Arguments:

opts (object) – Optional export options.
opts.channels (string[]) – Subset of channel names to include.
opts.nullValue (number) – Numeric null marker in the output. Defaults to -9999.25.

Returns:

LAS 2.0-formatted string.

Return type:

string

const las = frame.toLAS({ channels: ['DEPTH', 'GR', 'CALI', 'RHOB'] });
writeFileSync('well.las', las);