Selection Widget in GIS

What is Selection in GIS?

Selection in Geographic Information Systems (GIS) refers to the process of choosing specific objects or data from a vast array of geographic information. These objects can be points, lines, polygons, or other geo-objects, and the data may include information about location, object characteristics, or other attributes.

The goal of selection is to simplify working with large datasets by focusing on a manageable subset.

Why Use Selection?

Selection is widely used in GIS for several key reasons:

• Speed and Efficiency: Working with large datasets often requires significant processing time. Selection allows analysts to perform preliminary analysis more quickly, identifying trends and patterns without processing the entire dataset.

• Handling Spatial Variability: Geospatial data is often heterogeneous, meaning its characteristics can vary significantly depending on location.

• Preliminary Analysis: Selection is frequently used in the early stages of projects to study data and identify key trends, patterns, or outliers.

Applications of Selection in GIS

Ecology and Environmental Protection:

• Selecting data on biogeographic objects to assess ecosystem health.

• Highlighting areas with high pollution levels for further research.

Urban Planning:

• Zoning data selection for planning and designing urban spaces.

• Analyzing building density and identifying flood-risk zones.

Natural Resource Management:

• Identifying areas for resource extraction or conservation, such as forests for logging or wildfire prevention.

• Monitoring landscape changes to develop sustainable land-use methods.

Transportation and Logistics:

• Selecting specific road types or transport hubs for route planning.

• Evaluating traffic density and selecting data on congestion for optimizing transport flows.

Land Cadastre and Property Management:

• Selecting data to determine ownership rights, tax obligations, and cadastral measurements.

Agriculture:

• Analyzing farmland, selecting plots for specific crops, and monitoring crop conditions.

Healthcare:

• Analyzing disease spread and selecting geographic areas with high infection rates for preventive measures.

Emergency Management and Safety:

• Highlighting risk zones (e.g. earthquakes or floods) to create evacuation maps and plan rescue operations.

Marketing and Sales:

• Analyzing store locations and population density to identify potential markets or store placements.

Archaeology and Historical Heritage:

• Selecting archaeological sites or historical landmarks for research and preservation.

How to Use the Selection Widget in GISCARTA

In GISCARTA, the Selection widget works with both vector layers and vector tiles. It allows users to gather statistics on numerical fields from selected objects within a chosen layer, including:

• Total number of objects

• Maximum value

• Minimum value

• Average value

• Standard deviation

• Sum

Step 1: Enable the Selection Widget

1. Navigate to the Widgets section in the side menu panel.

2. Enable the Selection widget by toggling the switch next to its name.

The widget icon (a cursor) will appear on the toolbar at the bottom of the map workspace.

Step 2: Configure the Widget

1. Select the widget icon from the toolbar to open its window.

2. Choose from six selection methods:

• Select: Selection of a single object.

• Square: Selection of objects within the area of a drawn rectangle.

• Circle: Selection of objects within the area of a drawn circle.

• Polygon: Selection of objects within the area of a drawn polygon.

• Lasso: Selection of objects within the area of a freehand-drawn shape.

• Service areas: Selection of objects within the transport accessibility area from a specified point.

3. After choosing a selection method, configure the layer and field for which data statistics will be collected.

Step 3: View and Export Results

1. Once configured, the widget displays summarized information about the selected objects.

2. Selection results can be exported in the following formats for further analysis:
   To export, click the arrow icon in the upper-right corner of the widget window.

• XLSX

• GeoJSON

• SHP

To clear the selection and start over, click the brush icon in the upper-right corner of the widget window.

Benefits of the Selection Widget

The Selection widget streamlines and accelerates data analysis, especially when working with large datasets that are too extensive for full processing. It enables targeted exploration and efficient data handling, making it an essential tool for GIS professionals.