Metadata

It is recommended that any metadata associated with the original elevation data be stored in the same directory as the data files. In some cases such data is very limited, while other times the metadata can be too extensive for most applications.

Commonly used metadata should be populated into the attribute table of the mosaic datasets so that it can be quickly reviewed and also used for queries and sorting. If users require the more extensive metadata, it is best to add a Link2Metadata field (see below) into the attribute table, populated with the path and file name to detailed metadata files. This will enable users to locate the detailed metadata for any record in the system.

The following list provides the recommended field names and data types for commonly used metadata fields related to elevation data. Users may choose to add other fields to the mosaic datasets.

• LE90 [Float]—Horizontal Accuracy in meters.
• CE90 [Float]—Vertical Accuracy in meters.
• Date_Start [Date]—In some cases, elevation data collections are compiled from multiple sources over an extended time. This would be the earliest date represented in the data. For new elevation datasets generated via electronic sensors (lidar, IFSAR, radar, and so on), it is recommended to store the acquisition date in this field.
• Date_End [Date]—This is generally the date the elevation data was published, or if available, the date of the most recent data collection.
• DEM_Type [Short]—Elevation data may represent a number of different types, so this field is recommended for querying records of each type. Values used by Esri are as follows:
  • Undefined = 0
  • DSM (digital surface model, for example, lidar first return) = 1
  • DEM (bare earth) = 2
  • Bathymetry = 3
  • Ice (for example, ETOPO, GTOPO) = 4
• Best [Float]—It is recommended to use a custom field to define the order of which image appears on top within a mosaic by setting the default Mosaic Method property to By Attribute and using the attribute Best. See below for calculating the Best value.
• VerticalDatum [Text16]—NAVD88, EGM96, NGVD29, and so on.
• Dataset_ID [Text16]—When following the source/derived/referenced model, all records from each collection (for example, NED 1/3 arcsecond versus NED 1 arcsecond) will be combined in the derived mosaic dataset. Adding and populating this field in each source mosaic dataset with a unique identifier will allow a simple query within the derived mosaic dataset to identify records from each collection.
• Source_URL [Text64]—Use this field to record a link to the original source of the data.
• Link2Metadata [Text100]—Path and file name to detailed metadata files to allow user download.

These fields are typically added to the source mosaic datasets and will then be copied into the derived mosaic datasets.