earth science markup language tutorial on how to write an esml description file (for esml schema...

EARTH SCIENCE MARKUP LANGUAGE

Tutorial on how to write an ESML Description File (for ESML Schema v3.0)

“Define Once Use Anywhere”

INFORMATION TECHNOLOGY AND SYSTEMS CENTERUNIVERSITY OF ALABAMA IN HUNTSVILLE

ESML Schema • ESML schema defines Syntactic metadata that describe the structure of the file in machine-

readable and -interpretable terms• Divide data formats into free form (ASCII, Binary) and structured (HDF-EOS, netCDF, etc)

Two Sections

• Part I– Writing ESML Description for free form formats in

ASCII, Binary– Examples

• Part II– Writing ESML Description Files for structured formats

• HDF-EOS• netCDF

Part I

• Goal:– To write an ESML Description File for a simple ASCII

data file– Show similar example for Binary data file– Show other capabilities

Writing an ESML File (1)

<a:ESML > <SyntacticMetaData> <Ascii> <Structure instances="1"> <Header name="SizeX" format="%d" /> <Header name="SizeY" format="%d" /> <Array occurs=“4"> <Array occurs=“5"> <Field name="BrightnessTemp" format="%d"/> </Array> </Array> </Structure> </Ascii> </SyntacticMetaData></a:ESML>

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SIMPLE ASCIIDATA FILE

ESML MARKUPFOR THE DATA FILE

The next slides will set describe how to write an ESML file for a simple ASCII file described below



DESCRIBING ONLY THESTRUCTURE

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SIMPLE ASCIIDATA FILE



DESCRIBE THEFORMAT

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SIMPLE ASCII DATA FILE



ENTIRE FILE CONTENTSINTO 1 LOGICAL

STRUCTURE

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DEFINE THE FIRST FIELD IN THE FILE:

HEADER INFORMATION

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DEFINE THE SECOND FIELD IN THE FILE:

HEADER INFORMATION

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DEFINE THE DATA FIELD IN THE FILE:PROVIDE SIZE AND

FORMAT INFORMATION


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CLOSE ALL THETAGS: ESML FILE

IS READY

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REMEMBER TO VALIDATE YOUR FILE AGAINST THE SCHEMA!

<a:ESML > <SyntacticMetaData> <Ascii> <Structure instances="1"> <Header name="SizeX" format="%d" symbol=“true" /> <Header name="SizeY" format="%d“ symbol=“true" /> <Array occurs=“$SizeX"> <Array occurs=“$SizeY"> <Field name="BrightnessTemp" format="%d"/> </Array> </Array> </Structure> </Ascii> </SyntacticMetaData></a:ESML>

Another Possible ESML Description (9)

USE HEADER INFORMATION

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ESML Description for a similar file in Binary format

<a:ESML xsi:schemaLocation="ESML ../../Schema/ESML.xsd"> <SyntacticMetaData> <Binary> <Structure name="Bin" instances="1"> <Header type="Int32" name="sizeX"/> <Header type="Int32" name="sizeY"/> <Array occurs="5"> <Array occurs="5"> <Field name="BrightnessTemp" type="Int32" order="LittleEndian"/> </Array> </Array> </Structure> </Binary> </SyntacticMetaData></a:ESML>

ESML Description File using wild card ‘*’ to read till the end of file

<a:ESML xsi:schemaLocation="ESML ../../Schema/ESML.xsd"> <SyntacticMetaData> <Binary> <Structure name="Bin" instances="1"> <Header type="Int32" name="sizeX"/> <Header type="Int32" name="sizeY"/> <Array occurs=“*"> <Array occurs="5"> <Field name="BrightnessTemp" type="Int32" order="LittleEndian"/> </Array> </Array> </Structure> </Binary> </SyntacticMetaData></a:ESML>

Part II

• Goal:– Show some example ESML Description Files for

structured data formats supported by the ESML Schema

• HDF-EOS• netCDF• HDF5• Grib• WSR88DLII

<a:ESML > <SyntacticMetaData> </HdfEos> </SyntacticMetaData> </a:ESML>

ESML Descriptions for a Structured Format (HDF-EOS)

<a:ESML > <SyntacticMetaData> <HdfEos> <Structure name="CERES_ES8_12891" instances="1"> <Field name="Colatitude of CERES FOV at TOA“/> <Field name="Longitude of CERES FOV at TOA“/> <Field name="Time of observation“/> </Structure> </HdfEos> </SyntacticMetaData></a:ESML>

Both ESML Descriptions are correct and valid

<a:ESML > <SyntacticMetaData> </netCDF> </SyntacticMetaData> </a:ESML>

ESML Descriptions for a Structured Format (netCDF)

<a:ESML > <SyntacticMetaData> <netCDF>

<netCDFField name="U"></netCDFField>

</netCDF> </SyntacticMetaData></a:ESML>

Both ESML Descriptions are correct and valid

REMEMBER TO CHECK THE ESML REGISTRY FOR ALREADY EXISTING ESML DESCRIPTION FILE!!

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