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

package org.apache.sis.metadata.iso.spatial
Information about the mechanisms (grid or vector) used to represent spatial data. 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 `├─` Spatial representation «abstract» `│ ├─` Vector spatial representation `│ └─` Grid spatial representation `│ ├─` Georeferenceable `│ └─` Georectified `├─` Geolocation information «abstract» `│ └─` GCP collection `├─` GCP `├─` Dimension `└─` Geometric objects Code list `├─` Topology level `├─` Geometric object type `├─` Cell geometry `├─` Pixel orientation `├─` Dimension name type `└─` Spatial representation type | Spatial representation «abstract» Vector spatial representation `├─` Topology level «code list» `└─` Geometric objects `└─` Geometric object type «code list» Grid spatial representation `├─` Dimension `│ └─` Dimension name type «code list» `└─` Cell geometry «code list» Georeferenceable `└─` Geolocation information «abstract» Georectified `├─` Pixel orientation «code list» `└─` GCP GCP collection Spatial representation type «code list»

## Null values, nil objects and collections

All constructors and setter methods accept `null` arguments. A null argument value means that the metadata element cannot 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

- Related Packages
  Package
  Description
  org.apache.sis.metadata.iso
  Root package for ISO 19115 metadata about resources (data or services).
- Classes
  Class
  Description
  AbstractGeolocationInformation
  Information used to determine geographic location corresponding to image location.
  AbstractSpatialRepresentation
  Method used to represent geographic information in the dataset.
  DefaultDimension
  Axis properties.
  DefaultGCP
  Information on ground control point.
  DefaultGCPCollection
  Information about a control point collection.
  DefaultGeometricObjects
  Number of objects, listed by geometric object type, used in the dataset.
  DefaultGeorectified
  Grid whose cells are regularly spaced in a geographic or projected coordinate reference system.
  DefaultGeoreferenceable
  Grid with cells irregularly spaced in any given geographic/map projection coordinate reference system.
  DefaultGridSpatialRepresentation
  Method used to represent geographic information in the dataset.
  DefaultVectorSpatialRepresentation
  Information about the vector spatial objects in the dataset.