DigitalSurf SUR / PRO

Status: Supported · Vendor: Digital Surf · Extensions: .sur, .pro

.sur and .pro are the Digital Surf MountainsMap container formats, used for surface metrology, profilometry and AFM/Raman exports. nirs4all-formats reads the spectral and surface objects: spectra and hyperspectral maps become spectral records, while height surfaces become spatial profile records. These files are adjacent to the core NIRS point-spectrum scope.

Instruments & software

Written by Digital Surf MountainsMap and instruments that export through it (profilometers, AFM, branded AFM-Raman). The committed fixtures come from RosettaSciIO.

File structure

The reader sniffs the 12-byte signature DIGITAL SURF (uncompressed) or DSCOMPRESSED (zlib) and reads a fixed 512-byte little-endian object header. Multi-object files concatenate objects; the first header declares number_of_objects and p_size. Decoded header fields include object type, point size, X/Y dimensions, optional W size, axis names and units, offsets, spacings, scaling parameters, comment size, private-zone size and compressed payload size.

Compressed payloads are not RLE: a small directory (stream_count, then per-stream raw/zlib lengths) precedes the zlib streams. Raw points are signed 16-bit or 32-bit integers; for spectral/profile payloads the decoded value is (raw_int - z_min) * (z_spacing / z_unit_ratio) + z_offset.

What nirs4all-formats extracts

  • Signals — _SPECTRUM objects emit one record (single) or one record per spectrum (multi); _HYPCARD hyperspectral maps emit one SpectralRecord per XY point; _SURFACE height maps emit one profile record per row.

  • Axis — wavelength axes stored in mm by MountainsMap are normalised to nm in the SpectralAxis; the original DigitalSurf axis name and unit are preserved as signal_axis_name / signal_axis_original_unit. Surface rows use a spatial-index axis.

  • Metadata — maps add map_x_index, map_y_index, dimensions and map_axis_order = y_slowest_x_fastest; surfaces add spatial_y_index, X/Y spatial units and surface_axis_order = row_profiles_y_slowest_x_fastest.

  • Provenance & warnings — surface objects carry an explicit warning because their axis is spatial rather than spectral.

Variants & support status

Variant

Status

Notes

_SPECTRUM single / multi-spectrum profile

Supported

Multi-spectrum carries line-position metadata.

_HYPCARD hyperspectral map

Supported

One record per XY point; uncompressed and zlib payloads.

_SURFACE height map

Supported

One spatial profile per row; flagged as non-spectral.

DSCOMPRESSED zlib payloads

Supported

Directory-plus-zlib-stream decoding.

Limitations & known gaps

  • Object/comment metadata is decoded only at a basic level; richer object and comment fields are still pending.

  • Automated full-array conformance against rsciio.digitalsurf is not yet wired up.

  • The scope for MountainsMap variants outside this corpus, including branded AFM-Raman exports, is still undecided.

Reference readers

Layout and fixture values cross-checked against rsciio.digitalsurf 0.13.0. RosettaSciIO is GPL-3.0; it is used only as an external conformance reference and is never imported or linked by the MIT runtime.

Samples & validation

The RosettaSciIO fixtures under samples/digitalsurf/ are fully golden-backed: a single spectrum and a 65-spectrum profile (.pro), a 12-by-10 hyperspectral map and its zlib-compressed counterpart (120 records each, .sur), and a 128-row height surface exported as spatial profiles. No blocking samples are known; the open items are conformance and scope decisions.