# Package org.apache.sis.metadata.iso.acquisition

Information about the measuring instruments, the platform carrying them, and the mission to which the data contributes. An explanation for this package is provided in the OpenGIS® javadoc. The remaining discussion on this page is specific to the SIS implementation.
Overview
For a global overview of metadata in SIS, see the `org​.apache​.sis​.metadata` package javadoc.

Package overview
Class hierarchy | Aggregation hierarchy
--- | ---
ISO 19115 metadata `├─` Acquisition information `├─` Objective `├─` PlatformPass `├─` Event `├─` Requirement `├─` Requested date `├─` Plan `├─` Operation `├─` Platform `├─` Instrument `└─` Environmental record Code list `├─` Objective type `├─` Trigger `├─` Context `├─` Sequence `├─` Priority `├─` Geometry type `└─` Operation type | Acquisition information `├─` Requirement `│ ├─` Requested date `│ └─` Priority «code list» `├─` Objective `│ ├─` Objective type «code list» `│ └─` Platform pass `│ └─` Event `│ ├─` Trigger «code list» `│ ├─` Context «code list» `│ └─` Sequence «code list» `├─` Plan `│ ├─` Geometry type «code list» `│ └─` Operation `│ ├─` Operation type «code list» `│ └─` Platform `│ └─` Instrument `└─` Environmental record

Null values, nil objects and collections
All constructors and setter methods accept `null` arguments. A null argument value means that the metadata element can not be provided, and the reason for that is unspecified. Alternatively, users can specify why a metadata element is missing by providing a value created by `NilReason​.createNilObject(Class)`.

Unless otherwise noted in the Javadoc, all getter methods may return an empty collection, an empty array or `null` if the type is neither a collection or an array. Note that non-null values may be `NilObject`s.

Unless the metadata object has been marked as unmodifiable and unless otherwise noted in the Javadoc, all collections returned by getter methods are live: adding new elements in the collection modify directly the underlying metadata object.

Since:
  0.3

Defined in the `sis-metadata` module

- Class Summary
  Class | Description
  --- | ---
  DefaultAcquisitionInformation | Designations for the measuring instruments, the platform carrying them, and the mission to which the data contributes.
  DefaultEnvironmentalRecord | Information about the environmental conditions during the acquisition.
  DefaultEvent | Identification of a significant collection point within an operation.
  DefaultInstrument | Designations for the measuring instruments.
  DefaultObjective | Describes the characteristics, spatial and temporal extent of the intended object to be observed.
  DefaultOperation | Designations for the operation used to acquire the dataset.
  DefaultPlan | Designations for the planning information related to meeting the data acquisition requirements.
  DefaultPlatform | Designation of the platform used to acquire the dataset.
  DefaultPlatformPass | Identification of collection coverage.
  DefaultRequestedDate | Range of date validity.
  DefaultRequirement | Requirement to be satisfied by the planned data acquisition.