Using netCDF-Java Maven Artifacts

Using netCDF-Java Maven Artifacts

We make the netCDF-Java library available as Maven artifacts. To use them in your build, you need to add the Unidata Releases repository:

<!-- In Maven -->
<repositories>
    <repository>
        <id>unidata-all</id>
        <name>Unidata All</name>
        <url>https://artifacts.unidata.ucar.edu/repository/unidata-all/</url>
    </repository>
</repositories>

// In Gradle
repositories {
    maven {
        url "https://artifacts.unidata.ucar.edu/repository/unidata-all/"
    }
}

Next, select modules based on the functionality you need. In the minimal case, you’ll just want cdm-core and a logger. cdm implements the CDM data model and allows you to read NetCD-3 files (and a number of other file types). An example using JDK14 logging:

<!-- In Maven -->
<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>cdm-core</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>compile</scope>
</dependency>

<dependency>
  <groupId>org.slf4j</groupId>
  <artifactId>slf4j-jdk14</artifactId>
  <version>${slf4jVersion}</version>
  <scope>runtime</scope>
</dependency>

// In Gradle
dependencies {
  compile "edu.ucar:cdm-core:${netcdfJavaVersion}"
  runtime "org.slf4j:slf4j-jdk14:${slf4jVersion}"
}

There are optional modules add support for reading (and sometimes writing) various scientific data formats. To see which optionals you need for your data format, see here.

You can include any number of the optional components. For example, in Maven and Gradle:

<!-- In Maven -->
<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>bufr</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>runtime</scope>
</dependency>

<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>cdm-image</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>runtime</scope>
</dependency>

<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>grib</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>runtime</scope>
</dependency>

<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>netcdf4</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>runtime</scope>
</dependency>

<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>opendap</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>runtime</scope>
</dependency>

<dependency>
  <groupId>edu.ucar</groupId>
  <artifactId>cdm-mcidas</artifactId>
  <version>${netcdfJavaVersion}</version>
  <scope>runtime</scope>
</dependency>

// In Gradle
dependencies {
  runtime "edu.ucar:bufr:${netcdfJavaVersion}"
  runtime "edu.ucar:cdm-image:${netcdfJavaVersion}"
  runtime "edu.ucar:grib:${netcdfJavaVersion}"
  runtime "edu.ucar:netcdf4:${netcdfJavaVersion}"
  runtime "edu.ucar:opendap:${netcdfJavaVersion}"
  runtime "edu.ucar:cdm-mcidas:${netcdfJavaVersion}"
}

Building with netcdfAll

This is the appropriate option if you’re not using a dependency management tool like Maven or Gradle and you don’t care about jar size or compatibility with other libraries. Simply include netcdfAll-${netcdfJavaVersion}.jar on the classpath when you run your program. You’ll also need a logger. Currently does not include cdm-s3 due to the size of the AWS S3 SDK dependency.

Logging

The netCDF-Java library uses the SLF4J logging facade. This allows applications to choose their own logging implementation, by including the appropriate jar file on the classpath at runtime. Common choices are JDK logging and Log4J 2:

JDK Logging

You must include the SLF4J-to-JDK Logging interface jar: slf4j-jdk14-${slf4jVersion}.jar.

The actual logging is implemented in the java.util.log package, part of the Java runtime.

To configure JDK logging:

Modify the file $JAVA_HOME/jre/lib/logging.properties. Or, create you own logging properties file and specify it with the java.util.logging.config.file system property.

Possible log levels are SEVERE, WARNING, INFO, CONFIG, FINE, FINER, FINEST, and ALL.

To show only SEVERE messages for all loggers, use: .level= SEVERE

You can also set the configuration by using java.util.logging.LogManager in your application, most likely by creating your own properties file or resources and calling:

FileInputStream inputStream = new FileInputStream("my.properties");
LogManager lm = java.util.logging.LogManager.getLogManager();
lm.readConfiguration(inputStream);

Log4j 2

You must include the Log4j 2 SLF4J Binding (log4j-slf4j-impl-${log4j2Version}.jar) and the Log4j 2 implementation (log4j-core-${log4j2Version}.jar) on the classpath.

You should then configure the logging by adding a log4j2.xml config file to your classpath. A minimal version is:

<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="WARN">
  <Appenders>
    <Console name="Console" target="SYSTEM_OUT">
      <PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
    </Console>
  </Appenders>
  <Loggers>
    <Root level="error">
      <AppenderRef ref="Console"/>
    </Root>
  </Loggers>
</Configuration>

See the SLF4J manual for more possibilities.