A quick tour of creating and editing metadata
The Description tab lets you view and edit metadata for ArcGIS items and stand-alone metadata XML files. The pages available for editing metadata help you author content correctly for your metadata style. The default value for metadata style, Item Description, lets you create a concise description for an item. To create complete metadata for an item instead, choose a different metadata style.
ArcGIS Desktop 10 is designed to support creating and managing ArcGIS metadata in the Description tab. If an ArcGIS item or an XML file has existing metadata that was created using ArcGIS Desktop 9.3.1 or an earlier release, it must be upgraded to the ArcGIS metadata format before you can edit the existing content.
Existing ESRI-ISO metadata will be upgraded automatically when you start editing the item's metadata with the current release of ArcGIS.
If an item has existing FGDC metadata, you don't need to upgrade to ArcGIS metadata to maintain the level of information available with the default Item Description metadata style. This lets you easily maintain the amount of information necessary to publish resources to ArcGIS Online. Any changes you make on the Item Description page will update both the ArcGIS metadata elements and the associated FGDC metadata elements, if they are present in the item's metadata.
However, to maintain an item's complete, standard-compliant metadata using the editor available in the Description tab you must first upgrade the existing FGDC metadata to ArcGIS metadata. Complete FGDC metadata content won't be upgraded automatically—your organization must decide when it is appropriate for you to upgrade. For example, you might have to modify your workflow for validating and publishing metadata before you can upgrade and start using the ArcGIS metadata editor to maintain your content.
In the meantime, you can continue to maintain your FGDC metadata content using the FGDC metadata editor add-in. This add-in provides a button that can be added to the ArcCatalog Metadata toolbar. When clicked it will open the same FGDC metadata editor provided with ArcGIS Desktop 9.3.1 and earlier releases. All FGDC metadata content must be updated manually. ArcGIS 10 only automatically updates content in ArcGIS metadata elements.
Describing a collection of GIS resources
Most items in ArcGIS let you create metadata describing them. Each ArcGIS item has an individual metadata document that is not interconnected with other related ArcGIS items. For example:
- A feature class' metadata describes only that feature class—it does not inherit any information from metadata for the feature dataset in which the feature class is stored.
- A feature dataset's metadata describes only that feature dataset—it doesn't aggregate information about all the feature classes it contains.
- A layer file's metadata should describe only the layer and not the underlying data. It might describe the map scales where the data will be displayed, why the data was normalized using the chosen method, and how the features included in the layer were selected. The feature class should be documented as a related resource.
- A map service's metadata should describe only the map service. If appropriate, the underlying map and the data services it contains should be documented as related resources.
If you have already created metadata describing a feature dataset, you don't need to retype portions of its description into the metadata for all the feature classes it contains. You can import the feature dataset's description to the feature class using the Import button in the Description tab and the FROM_ARCGIS import type. The feature dataset's description will be copied, while the intrinsic properties of the feature dataset will not—the intrinsic properties of the feature class will be added automatically. Be sure to update the imported description so it correctly describes the item. By the same token, metadata can be copied from one item to other related items using the same workflow.
If some information is the same for many items, the best workflow is to create a metadata template that exclusively contains the common information. Then, import the template to an item before you start creating its metadata.
ISO metadata standards support the idea of maintaining information at different hierarchical levels in a GIS. For example, you might create metadata describing an entire series of imagery instead of creating almost identical descriptions for each image in the series. In ArcGIS, you can create metadata describing more granular resources such as a series or an entire data product by creating a stand-alone metadata XML file and adding metadata to it in the Description tab.
ISO metadata standards also suggest that you can create metadata describing parts of an item such as the attributes or features in a feature class. Creating metadata at this level of detail is not supported in ArcGIS. Information about a feature should be documented in the feature class' attribute table. Information about an attribute can be documented in the Fields section in the feature class' metadata.
In an ArcSDE geodatabase, metadata can only be created to describe items in the default version. Individual transactional or historical versions of the geodatabase can't have metadata that is specific to the items in that version. If you change metadata when you are using a transactional or historical version of the geodatabase, your changes will be seen by everyone using the default version of the geodatabase; your changes may not be relevant for the default version.
A plan for metadata
As with any project, you'll need a plan in place for your organization identifying what items need metadata, which metadata standard or profile you're going to follow, and who is responsible for completing what portion of the documentation. Even if one person enters all the metadata, that person needs the people who created the data to provide information about how it was created and tested, for example. It helps to have organizational support to ensure that all participants will contribute their time and knowledge so the project will succeed.
If several people will be creating metadata, the manager of the metadata project should create metadata templates for others to use and provide some guidelines to ensure consistency. This person should also check that completed metadata is valid and coordinate publishing completed metadata to a metadata catalog if you decide to share your information.
When developing guidelines for your organization, be sure to use common sense. There is more to consider than the rules of a metadata standard. Your metadata should be as complete as it needs to be for its intended purpose. The absolute minimum amount of information required to make metadata valid for a metadata standard may be insufficient to find it when you search a metadata catalog. The absolute minimum amount of information required to publish metadata to a metadata catalog may be insufficient for it to be valid for a metadata standard.
Most of your effort should be spent documenting the data you use most, as it is the most valuable to your organization.
After creating metadata for a few metadata items, be sure to review the work. If the metadata has been published to a metadata catalog, do some searches to see if you can find your documents. You may want to modify your guidelines to improve the work you do in the future.
What documentation to provide
Metadata elements can typically be divided into two categories: documentation and properties.
Documentation is descriptive information supplied by a person when he or she edits information in the Description tab such as the units of measure for data stored in a field and the information that data represents. Good documentation protects your investment in the resources you have created. You can have more confidence in your decisions when you know your data is accurate, current, and came from a reliable source.
Properties describe inherent characteristics of the item such as the extent of features in a feature class or the location of a text file. By default, ArcGIS derives an item's properties and adds them to its metadata automatically when metadata is viewed, validated, exported, and imported. Properties can also be updated in an item's metadata using the Synchronize Metadata tool whenever it is appropriate to do so. Adding properties to metadata automatically supplements good documentation and helps reduce metadata maintenance costs. Because ArcGIS automatically handles the properties, all you need to worry about is completing the documentation.
If metadata is automatically created and updated by ArcGIS, when you view it, you will always see current information describing the item. Information that is maintained automatically is best left unmodified except for the default title of the item. If you change an automatically added value, the metadata element changes categories—from properties to documentation—and the value won't be updated automatically in the future if the item changes.
In general, your metadata should cover the who, what, when, where, why, and how of the ArcGIS item. Here are just a few tips to get you thinking before you start editing metadata:
- ArcGIS will index the title, abstract, purpose, keyword, and credit metadata elements for searching.
- Since "now" will become "then," and you will forget, try to provide a real date or a range of dates describing when the data was created. Avoid using relative terms like now or present unless people truly update a resource daily over an extended period of time.
- Consider the date of the source data when describing the date of an item. Data created today using an image that is six months old is really six months old. You can enter two times, one for when the image was captured and one for when the data was created from the image; just be sure to indicate which date is for which event.
- When providing contact information, try to use a position name or the name of a group instead of a person's name unless creating the data is truly an individual effort. People leave an organization or change roles, and the cost of updating metadata to change a person's name is not insignificant.
- If you produce different versions of a map or data, it is important to identify which version you are describing with the edition metadata element in the item's citation. The version being described might be obvious when you are in ArcGIS, but if the metadata is published to a metadata catalog, it might not be easy to determine.
- Thumbnails aren't strictly part of any metadata standard, so not all metadata catalogs support them. However, when you search a metadata catalog based on ESRI software, a thumbnail can help you decide immediately if you've found the right item.
- If someone who has never seen your data before wants to use it, what do they need to know? What are they allowed to do with it?