# Data

JMap NG projects can contain two types of data: spatial data and non-spatial data.

## Spatial Data

Spatial data is organized into map layers. Each layer contains data on a particular theme. These layers are overlaid to form the map displayed in the interface.

### Types of Cartographic Layers

#### **Vector Layers**

Vector layers are composed of features represented by geometries (points, lines, polygons) and descriptive attributes.

Example: A tree layer represented by points, with attributes such as species, diameter, height, and health status. Each tree thus has a geographic position and characteristics that describe it.

#### **Raster Layers**

Raster layers are composed of pixel-based data forming images, such as aerial photographs, satellite imagery, and digital terrain models.

### **Hierarchical Organization**

Layers can be grouped hierarchically by theme: urban planning, environment, transport, etc. This multi-level structure facilitates navigation when projects contain numerous layers.

### **Base Maps**

Base maps provide a visual context for presenting your data. Your interaction is limited to selecting which base map to display.

## Non-Spatial Data

Non-spatial data in the project is organized into tables. This tabular data can be linked to map layers or be completely independent.

A table contains rows (records) and columns (fields or descriptive attributes).