McIDAS Programmer's Manual
Version 2003

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DC*

MD schema definition files.

Schema definition files are ASCII text files that contain lines of text defining the structure of MD files for point-source data types. To create a schema definition file, use a standard editor to enter a set of text lines. The file serves as input to the schema registration program, SCHE, that reads the text lines and forms a blueprint of the MD file's structure. SSEC distributes the schema definition files below with every McIDAS upgrade.

Schema file Contents

DCFO14

NGM MOS forecasts

DCIRAB

international radiosonde observations

DCISEN

isentropic data

DCISFC

international surface hourly observations

DCISHP

international ship and buoy observations

DCPIRP

PIREP, AIREP and ACARS data

DCSYN

surface synoptic observations

Because schema definition files form the input to an application, you must use the formats provided below for each text line of a schema file.


File header

A header is required for each schema definition file. Its format is shown below, followed by a table of parameter definitions.

SCHEMA name version date id "description

Parameter Definition

name

four-character schema name

version

schema version number

date

Julian day the schema definition file was created

id

schema identification number

"description

comments


Row and column headers

Either a row header or a column header is required for each schema definition file. The row and column header formats are shown below, followed by a table of parameter definitions.


ROWS nrows "description
rkeyname1 rscale1 runits1
"description
...
rkeynameN rscaleN runitsN
"description

Parameter Definition

nrows

default number of rows to make for this MD file

rkeyname1 ... N

name of the first and Nth row header keys

rscale1 ... N

scale factor of the first and Nth row header keys

runits1 ... N

physical units of the first and Nth row header keys

"description

comments


COLUMNS ncols "description
ckeyname1 cscale1 cunits1
"description
...
ckeynameN cscaleN cunitsN
"description

Parameter Definition

ncols

default number of columns to make for this MD file

ckeyname1 ... N

name of the first and Nth column header keys

cscale1 ... N

scale factor of the first and Nth column header keys

cunits1 ... N

physical units of the first and Nth column header keys

"description

comments


Data lines

Use the format below for the data lines.

DATA
dkeyname1 dscale1 dunits1 "description
...
dkeynameN dscaleN dunitsN
"description

Parameter Definition

dkeyname1 ... N

name of the first and Nth data keys

dscale1 ... N

scale factor of the first and Nth data keys

dunits1 ... N

physical units of the first and Nth data keys

"description

comments


Repeat groups

Repeat groups are optional. They are useful when data of the same type is repeated within the data portion of a record. The format is shown below.

REPEAT nrepeats
rkeynames rscales runits
"description

Parameter Definition

nrepeats

number of repeat groups in the data portion of the schema definition

rkeynames

names of the repeated data keys

rscales

scale factors of the repeated data keys

runits

physical units of the repeated data keys

"description

comments


End-of-schema and comment formats

To end the schema definition file, use ENDSCHEMA. To enter comments, use the format "comments.


API functions

No API functions exist for reading and writing MD schema definition files.

 

For more information about MD file schemas and associated terminology, see the MDXXnnnn data structure in this chapter.


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