In today’s digital age, Geographic Information System (GIS) has become a critical tool for businesses, governments, and individuals alike. By collecting, analyzing, and presenting data in a geographic context, GIS helps people make better decisions about where to live, work, and play. However, to make the most of GIS, it’s essential to understand what GIS metadata is and how it works.
What is GIS Metadata?
GIS Metadata refers to the information about the characteristics of spatial data. It is a set of data that describes the contents, quality, and condition of geographic data. Metadata provides a detailed description of the data, such as the title, abstract, keywords, projection information, and data quality information.
GIS metadata can include a wide range of information, such as the data’s creator, the date it was created, the projection used, the data format, and the data’s scale. It can also include information about the data’s content, such as its attributes, spatial extent, and spatial reference system.
Why Is GIS Metadata Important?
GIS metadata is essential for ensuring the accuracy and reliability of geographic data. Without metadata, it’s difficult to know the origin and quality of the data, which can lead to errors and misinterpretations.
Metadata also provides critical information about the data’s suitability for specific applications, such as mapping, analysis, and modeling.
In addition to its practical importance, GIS metadata also plays a crucial role in data sharing and collaboration. By providing detailed information about the data, metadata helps ensure that others can understand and use it correctly.
How Is GIS Metadata Used?
GIS metadata is used in many ways to support data management, analysis, and decision-making. Some of the most common uses of GIS metadata include:
1. Discoverability and Accessibility
GIS metadata helps users to find and access data easily. Metadata provides information about the data’s location, format, and the data provider. This makes it easier for users to search for data and to determine if the data is relevant to their needs.
2. Data Sharing
GIS Metadata also facilitates data sharing. Metadata provides information about the data’s ownership, usage restrictions, and licensing agreements. This information helps data users to comply with legal and ethical obligations while using the data.
3. Data Quality
GIS Metadata provides information about the data quality, such as the accuracy, precision, and completeness of the data. This information helps users to evaluate the suitability of the data for their purposes.
4. Data Integration
GIS Metadata provides information about the data’s structure and format, which helps in integrating the data with other datasets. This integration helps users to analyze and visualize the data more effectively.
5. Decision Making
GIS Metadata helps decision-makers to understand the data and its limitations. Metadata provides information about the data’s source, processing, and accuracy, which helps in making informed decisions.
Types of GIS Metadata
GIS metadata is an important aspect of Geographic Information System (GIS) data management. It provides a detailed description of the characteristics and quality of spatial data, including its source, accuracy, and other relevant information. There are two main types of GIS metadata, which are:
Descriptive Metadata
This type of metadata describes the content of the spatial data. It includes information such as the title, abstract, and keywords. Descriptive metadata also provides information on the geographic extent of the data, the projection, and the coordinate system used. This type of metadata is useful for data discovery and retrieval.
Structural Metadata
Structural metadata provides information about the structure and format of the spatial data. It includes information such as the file format, schema, and database management system used. This type of metadata is important for data integration and analysis.
How Is GIS Metadata Created?
Creating GIS metadata involves capturing information about the data as it is created or processed.
The process of creating metadata typically involves two main steps: defining the metadata content and documenting the metadata.
Defining the metadata content involves determining what information should be included in the metadata based on the needs of the data users. This step typically involves identifying the most critical information about the data, such as its source, scale, and accuracy.
Documenting the metadata involves actually capturing and recording the metadata information in a standardized format. Many organizations use the Federal Geographic Data Committee’s (FGDC) Content Standard for Digital Geospatial Metadata as a guide for documenting GIS metadata.
Best Practices For Creating GIS Metadata
To ensure that GIS metadata is effective, it’s essential to follow best practices for metadata creation. Some of the most important best practices include:
1. Define the Purpose and Scope
The first step in creating GIS metadata is to define the purpose and scope of the metadata. This involves identifying the target audience for the metadata, the intended use of the data, and any specific requirements or standards that need to be met.
2. Choose the Metadata Standard
Once the purpose and scope have been defined, the next step is to choose the appropriate metadata standard to use. Common metadata standards for GIS data include ISO 19115 and FGDC CSDGM.
3. Gather Information
The next step is to gather all the relevant information about the spatial data. This includes information such as the data source, the spatial extent, the projection and coordinates system, the data format, and any quality control procedures.
4. Organize the Information
Once all the information has been gathered, it needs to be organized in a logical and structured manner. This involves creating different sections for descriptive, structural, spatial, temporal, quality, and usage metadata.
5. Use Standardized Vocabulary
When creating descriptive metadata, it is important to use standardized vocabulary and controlled keywords. This helps ensure consistency and improves the discoverability of the data.
6. Provide Accurate and Complete Information
All the information provided in the metadata should be accurate and complete. It should also be reviewed and validated by subject matter experts to ensure its accuracy.
7. Include Contact Information
It is important to include contact information for the data creator or owner in the metadata. This allows users to contact the creator or owner for additional information or to report any errors or issues.
8. Update Metadata Regularly
Metadata should be updated regularly to reflect any changes to the spatial data or to the metadata itself. This helps ensure that the metadata remains accurate and up-to-date.
By following these best practices, GIS professionals can create accurate and comprehensive metadata that supports effective data management and analysis.
GIS Metadata Example
The below XML code shows an example of GIS metadata for a dataset called “Map of Local Parks”. The metadata includes information about the dataset’s identification, distribution, data quality, and spatial representation. Here is an example of GIS metadata in XML format:
<?xml version="1.0" encoding="UTF-8"?>
<metadata xmlns="http://www.opengis.net/cat/csw/2.0.2"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://www.opengis.net/cat/csw/2.0.2
http://schemas.opengis.net/csw/2.0.2/CSW-discovery.xsd">
<identification>
<title>Map of Local Parks</title>
<abstract>This map shows the location of local parks and their amenities, such as playgrounds, sports fields, and picnic areas.</abstract>
<keywords>
<keyword>parks</keyword>
<keyword>recreation</keyword>
<keyword>amenities</keyword>
<keyword>map</keyword>
<keyword>Anytown</keyword>
</keywords>
<type>dataset</type>
<status>completed</status>
<responsibleParty>
<organization>
<name>City of Anytown Parks and Recreation Department</name>
</organization>
<role>owner</role>
</responsibleParty>
<date>
<dateType>creation</dateType>
<date>2021-01-01</date>
</date>
<date>
<dateType>publication</dateType>
<date>2021-06-01</date>
</date>
</identification>
<distribution>
<format>Shapefile</format>
<format>KMZ</format>
<format>PDF</format>
<transferOptions>
<online>
<url>http://www.anytown.gov/parks/maps</url>
</online>
<fees>None</fees>
</transferOptions>
</distribution>
<dataQualityInfo>
<scope>dataset</scope>
<lineage>
<statement>Attribute data was obtained from the Parks and Recreation Department records. Spatial data was obtained from aerial photography and field surveys.</statement>
<processStep>
<description>Attribute data was checked for accuracy and consistency with the Parks and Recreation Department's records.</description>
<dateTime>2021-02-01</dateTime>
</processStep>
<processStep>
<description>Spatial data was checked for logical consistency and any errors were corrected.</description>
<dateTime>2021-03-01</dateTime>
</processStep>
<processStep>
<description>Spatial data was georeferenced using a combination of GPS, aerial photography, and field surveys.</description>
<dateTime>2021-04-01</dateTime>
</processStep>
</lineage>
</dataQualityInfo>
<spatialRepresentationInfo>
<spatialRepresentationType>vector</spatialRepresentationType>
<vectorSpatialRepresentation>
<topologyLevel>geometry only</topologyLevel>
</vectorSpatialRepresentation>
<georectified>
<checkPointAvailability>unknown</checkPointAvailability>
</georectified>
<referenceSystemInfo>
<referenceSystemIdentifier>
<code>WGS 1984</code>
</referenceSystemIdentifier>
</referenceSystemInfo>
<axisDimensionProperties>
<dimensionName>easting</dimensionName>
<dimensionSize>9000</dimensionSize>
<resolution>10</resolution>
<dimensionTitle>Longitude (WGS 1984)</dimensionTitle>
</axisDimensionProperties>
In the identification section, the metadata includes the dataset’s title, abstract, keywords, type, status, responsible party, and creation and publication dates.
The distribution section provides information about the formats in which the dataset is available and how it can be transferred.
The data quality section includes information about the dataset’s lineage, which describes how the data was created, processed, and modified.
Finally, the spatial representation section includes information about the dataset’s spatial representation type, topology level, reference system, and axis dimension properties.
All of this information helps users understand the content, quality, and usability of the dataset.
Conclusion
GIS metadata is an essential part of any GIS project, providing critical information about the geographic data itself. By following best practices for metadata creation and ensuring that metadata is accurate, detailed, and up-to-date, GIS users can ensure that their data is reliable and suitable for the intended purpose. Metadata also supports data sharing, integration, and discovery, making it an essential component of any GIS project.
FAQs
What is the FGDC Content Standard?
The Federal Geographic Data Committee’s (FGDC) Content Standard for Digital Geospatial Metadata is a standardized format for capturing and documenting GIS metadata. It includes guidelines for documenting information about the data’s content, quality, accuracy, and other important details.
Why is metadata important in GIS?
Metadata is important in GIS because it provides critical information about the geographic data itself, such as its source, accuracy, and quality. This information is essential for understanding the reliability and suitability of the data for specific purposes.
How can GIS metadata support data sharing?
GIS metadata supports data sharing by providing detailed information about the data, ensuring that others can understand and use it correctly. By documenting the data’s content, quality, and other important details, metadata helps ensure that data is properly documented and can be shared with others.
What are the consequences of not documenting GIS metadata?
The consequences of not documenting GIS metadata can be significant. Without metadata, it’s difficult to know the origin and quality of the data, which can lead to errors and misinterpretations. Metadata also provides critical information about the data’s suitability for specific applications, such as mapping, analysis, and modeling.
How often should GIS metadata be updated?
GIS metadata should be updated regularly to ensure that it remains accurate and relevant as the data changes or new information becomes available. Metadata should be updated whenever changes are made to the data or its content, and at least once a year to ensure that it remains up-to-date.