Database System (Oracle, PostgreSQL, SQL Server, MySQL)
GIS Software (ArcGIS Desktop, QGIS, PostGIS, ArcSDE, ArcGIS Server, GeoServer)
Web Programming (HTML, CSS, JavaScript, PHP, Django, ASP.NET, Laravel)
Mobile Programming (Android Studio, Ionic Framework, Cordova)
Programming (C#, Java, Python, Visual Basic, C++)
Web GIS API (ArcGIS API for JavaScript, OpenLayers, Google Map API, Leaflet)
Remote Sensing Software (Erdas Imagine, ENVI)