When using GIS, these essential skills, critical thinking, analytical thinking, and spatial thinking, are all working together, however students need to be taught how to think and use these skills so they can create meaningful experiences. Scaffolding must happen in order for students to successfully integrate all three on their own.
Preparing 21st century students defines critical thinking as the ability to:
Reason Effectively
Use Systems Thinking
Make Judgements and Decisions
Solve problems
The Global Digital Citizen Foundation defines this skill set as the ability to:
compare
contrast
apply
synthesis
evaluate
The National Research Council defines this as a combination of
space concepts
representational tools
reasoning process
Don't just Dive into Project Based learning with GIS unless you feel confident in your skills and your students skills. Incorporating GIS in classroom instruction is a progression. You need to build up to PBL, begin with instructor guided activities that introduce your students to the technology and work your way into PBL.