Integrating the Climate Science Modelling Language with geospatial software and

services

Dominic Lowe (d.lowe@rl.ac.uk), British Atmospheric Data Centre

A.Woolf, B.N. Lawrence, S. Pascoe

Context

• Developed and deployed a metadata schema with associated services for the Atmospheric/Oceanographic application domain.

• Summary of issues encountered

• Almost exactly the process INSPIRE is mandating.

INSPIRE

• Data Specifications: 34 themes including Atmospheric Conditions, Oceanography, Meteorology

• “standardisation of formats and nomenclatures so that the data sets can be combined seamlessly and without manual intervention”

• “Interoperability is the ability of two or more autonomous entities, like web services or applications, to communicate and co-operate with each other in a meaningful way. This interaction should not require special efforts by the data producer or consumer -be it human or machine.(www.inspire-geoportal.eu)”

Aim to engage with GIS standards...

NetCDF, HDF, PP, GRIB, NASAAmes, ASCII, Databases...

?DataCentre

WMS

WCS

WFS

Metadata

ISO TC211 for Geographic Information

GML Application Schema

CSML – Climate Science Modelling Language

OGC

Climate Science Modelling Language

UML model & GML Application Schema

CSML Feature Types

AVHRR satellite imageryTwo-dimensional grid of data along a satellite ground-path

SwathFeature

numerical weather prediction model, ocean general circulation model

Time-series of gridded parameter fieldsGridSeriesFeature

gridded analysis fieldSingle time-snapshot of a gridded field.GridFeature

weather radarBackscatter profiles along a look direction at fixed elevation but rotating in azimuth

ScanningRadarFeature

marine CTD measurements along a ship’s cruise track

Series of profiles of unequal length along a trajectory in time and space

RaggedSectionFeature

shipborne ADCPSeries of profiles from positions along a trajectory in time and space.

SectionFeature

repeat daily balloon soundings of atmospheric temperature from the same location

Time-series of unequal-length profiles, but on fixed vertical levels, at a fixed location

RaggedProfileSeriesFeature

vertical radar timeseries, thermistor chain timeseries

Time-series of profiles on fixed vertical levels at a fixed location

ProfileSeriesFeature

wind sounding, XBT, CTD, radiosondeSingle ‘profile’ of some parameter along a vertical line in space.

ProfileFeature

2m temperatures measured at weather stations across the UK at 0600z.

Collection of distributed single datum measurements at a particular time

PointCollectionFeature

surface salinity along a ship’s cruise track; atmospheric aerosols along an aircraft’s flight path

Measurement along a discrete path in time and space.

TrajectoryFeature

tidegauge, rainfall timeseriesTime-series of single datum measurements at a fixed location in space.

PointSeriesFeature

raingauge measurementSingle point measurement.PointFeature

ExampleDescriptionFeature type

Problem solved?

NetCDF, HDF, PP, GRIB, NASAAmes, ASCII, Databases...

DataCentre

WMS

WCS

WFS

CSML Application Schema

OGC

??

Infrastructure components

XML HandlingCustom parser built for CSML Application Schema to read and write instance documents.

Investment needed in generic GML Application Schema parsers

CSMLDocuments

<GridFeature>...

</GridFeature>

PythonClasses

class GridFeature:...

toXML()

fromXML()

Provides API to CSML

documents

Creating instance documents

CSML Scanner

PointSeriesGridSeriesProfileSectionRadarSwath....

Features

Which feature type? which files? which file type? which variables? which coordinate reference system...?

References to stored data

CSML contains FileExtracts – pointers to data.

Goes beyond current GML practice of inline storage.

Essential for large volume data.

cd StorageDescriptor

«type»ArrayDescriptor

+ arraySize: int [1..*]+ id: ID+ numericTransform: string [0..1]+ numericType: string [0..1]+ regExpTransform: string [0..1]+ uom: UomIdentifier [0..1]

«type»InlineArray

+ values: anySimpleType [0..*]

«type»ArrayGenerator

+ expression: string

«Union»FileExtract

+ fi leList: FileList [0..1]+ fi leName: anyURI

«type»NASAAmesExtract

+ index: int [0..1]+ variableName: string

«type»NetCDFExtract

+ variableName: string

«type»GRIBExtract

+ ctlVariableName: string [0..1]+ fi leOffset: int [0..1]+ parameterCode: int+ recordNumber: int [0..1]

«type»AggregatedArray

+ aggIndex: int+ aggType: string

«type»CDMLExtract

«type»RawFileExtract

+ bitDepth: int [0..1]+ endianness: string [0..1]

«type»FileList

+ fi leNames: anyURI [0..*]

CSMLStorageDescriptor

+descriptor 0..*

+component

*

Extensible for different formats

Data access schema development in parallel with application schema development.

Harmonised data access layer

Sensible handling of multiple data formats requires robust plug-in data interface architecture.

CSML Code

Prototype developed, but more generic/robust system needed for other application domains.

Harmonised Data Interface layer

CDMSNaPP

YPILPILPILPIL SQL

Data APIs

Xlink in GML Application Schema

Describes the nature of the remote resource in relation to the referring GML element (“local resource”)

Describes the nature of the remote resource

<gmlElement xlink:arcrole="urn:ogc:def:contentprovider:OGC:1.0:direct" xlink:href="file:///myfile.nc#temperature" xlink:role="urn:ogc:def:fileformat:OGC:1.0:netcdf" xlink:show="embed"/>

See OGC Document: 07-083

Proposal to OGC – using XLINK to reference data. Requires more research. Beyond current GML practice for App. Schemas.

Vocabularies/Catalogues/Standard Terms

•Coordinate Reference Sytems in our application domain are not well catalogued. Hybrid Sigma Pressure Levels, etc.

•Catalogues and tools required to assist with identifying Coordinate Reference systems

•Ongoing work with standard vocabularies e.g. CF Standard Names. Assist greatly with axis identification.

•All these things aid automation and reduce human intervention.

Using common vocabularies and catalogues is critical for interoperability.

Summary

• Followed rules for application schema development

• Problem only partly solved!

• Many implementation issues to consider

• Opportunities for development of re-useable component

• INSPIRE is coming!