SPIF Mandatory Vocabulary

Introduction

This document provides details of the spif_example data product.

The standard REQUIRES that any SPIF compliant file contain a minimum set of groups, variables, and attributes. Any additional included vocabulary must not conflict with the mandatory vocabulary.

Vocabulary

/

Description:

This dataset contains the minimum required contents to satisfy the SPIF requirements.

File Pattern:

spif_example.nc

References:

SPIF standard

Group Attributes:

  • Conventions: SPIF-0.1

  • imager_groups: <str: derived_from_file>

/imager_1

Description:

Group containing image data from a single instrument or instrument channel.

Group Attributes:

  • instrument_name: imager_1

  • group_type: imager

Group Variables:

color_level

REQUIRED

Datatype:

<float32>

Dimensions:

pixel_colors

Description:

Lower bound of fractional obscuration/grayscale/color level of photo-detectors for each color_value.

array_size

REQUIRED

Datatype:

<int32>

Dimensions:

array_dimensions

Description:

Number of pixels on the detector in each dimension. If varying or undefined, use _FillValue.

image_size

REQUIRED

Datatype:

<int32>

Dimensions:

array_dimensions

Description:

Number of pixels across an image. If a fixed size then it will be the number of pixels, if of varying size along a dimension then use _FillValue.

resolution

REQUIRED

Datatype:

<float32>

Dimensions:

array_dimensions

Description:

Image resolution of instrument for each dimension.

wavelength

REQUIRED

Datatype:

<float32>

Dimensions:

Description:

Operating wavelength of laser used for shadowing/imaging the particles. If white light source then use _FillValue. If multiple wavelengths are used then use a coordinate array rather than scalar variable.

pathlength

REQUIRED

Datatype:

<float32>

Dimensions:

Description:

Optical path length of imaging region.

/imager_1/core

Description:

The imager core group containing the flattened image data and variables needed for reading that data.

Group Attributes:

  • group_type: core

Group Variables:

image

REQUIRED

Datatype:

<uint8>

Dimensions:

pixel

Description:

Flattened array of image pixel color values.

timestamp

REQUIRED

Datatype:

<uint64>

Dimensions:

image_num

Description:

Arrival time, relative to a reference start time, of the first pixel of an image.

Attributes:

  • standard_name: time

  • units: <str: derived_from_file>

startpixel

REQUIRED

Datatype:

<uint32>

Dimensions:

image_num

Description:

Array index of first pixel of an image.

width

REQUIRED

Datatype:

<uint8>

Dimensions:

image_num

Description:

Number of pixels across an image.

height

REQUIRED

Datatype:

<uint8>

Dimensions:

image_num

Description:

Number of slices/lines in an image.

overload

REQUIRED

Datatype:

<byte>

Dimensions:

image_num

Description:

Flag indicating an imager overload condition for each image.