Leaflet is a modern, lightweight open-source JavaScript library for creating mobile-friendly interactive maps for web developers.

OpenLayers is a high-performance, open-source JavaScript library for displaying dynamic maps and vector data on any web page.

HOT is a non-profit dedicated to humanitarian action and community development through OpenStreetMap data collection and mapping projects globally.

FOSS4G is the premiere annual conference for the global Free and Open Source Software for Geospatial community, focusing on mapping and geo-technologies.

OpenStreetMap is a free, community-created wiki world map, available for use under an open license, supported by partners.

OpenStreetMap is the best open source mapping tool for geolocation and is used by individuals and organizations worldwide.