GIS
Strong knowledge in the retrieval and use of 2D and 3D geodata, and in the use of geoprocessing, symbolization, visualization, labeling and layout tools.
Tools: QGIS | ArcGIS Pro | SQL | Python

Graphic Design
Creativity, and excellent knowledge in graphic design principles (colours, fonts, layout, etc.) and in cartographic principles.
Tools: Illustrator | Photoshop | InDesign

Data & Statistics
Skills to find data from many resources, perform exploratory analysis of data to find trends and insights, and perform advanced statistics. Design of attractive and effective data visualizations.
Tools: Excel | Python | R | Illustrator

And various other skills...
Remote sensing
Environmental sciences
UI/UX design
Web development
Logo design
Photogrammetry
Social and human sciences
Geomarketing
Web services
Interactive maps
Dashboards
Mathematics
Image processing
Data mining
Databases
Urban planning