Tweak intro texts to clearly distinguish data representation and data exchange.

#### 5.2.2.1 Introduction

This clause defines the general requirements for data representation (both input

and output) across all endpoints of the NGSI-LD API.

This clause defines the general requirements for data representation across the

NGSI-LD API.

#### 5.2.2.2 Supported text encodings

### 5.3.1 Introduction

This clause defines the representation of Entity data. Implementations shall be

able to represent Entity data using multiple media types (JSON-LD, GeoJSON). The

Attributes of an Entity can be returned in three different formats

(**normalised**, **concise**, **simplified**). When representing the [Temporal

Evolution of an Entity]{.HTML-Keyboard}, three additional attribute formats are

defined (**normalised**, **simplified**, **aggregated**).

This clause defines the representation of Entity data, for both input and

output. Implementations shall be able to represent Entity data using multiple

media types (JSON-LD, GeoJSON). The Attributes of an Entity can be returned in

three different formats (**normalised**, **concise**, **simplified**). When

representing the [Temporal Evolution of an Entity]{.HTML-Keyboard}, three

additional attribute formats are defined (**normalised**, **simplified**,

**aggregated**).

Unless otherwise specified, the default representation of an Entity shall use

Unless otherwise specified, the default interchange format of Entities shall use

JSON-LD and Attributes in the **normalised** format.

### 5.3.2 JSON-LD