Validating remote sensing observations
Adventure movies make it seem like satellites can see everything from space, but is this fact or fiction?
Remote sensing satellites provide us with lots of information, but as demonstrated by this image, they don’t tell us everything. We can see roofs, sunshades and trees – from which we can make inferences about these structures – but we can’t tell for certain what’s under the structures and what functions they may serve. For real proof, we need direct on-the-ground observations!
Satellite images and data
Satellite images give us useful data but they do not always provide the full picture. For example, the image shows buildings and structures but gives little evidence of what they are and how they are used. Making observations at ground level provides a fuller understanding.
This activity helps students discover the benefits of using satellite and ground-based observations to build a more accurate picture (or model) of what is being observed. Careful teacher questioning can aid students in transferring this experience to more-abstract satellite measurement scenarios.
In this activity, students use satellite images of their school or other well-known locations to practise the science capability ‘Gather and interpret data’. Comparing what they observe from space with what they directly observe on the ground enables students to explore the concepts of data validation and ground-truthing. Validation and ground-truthing are vital for ensuring the accuracy of the information we get from satellites.
observe a satellite image and describe what they see
make inferences about what is in the image (predictions about what they cannot directly observe)
observe the same location at ground level and describe what they see
make comparisons between the observations to ensure a match with the satellite image/location and observed objects
discuss whether their inferences are correct
discuss how both sets of observations provide more-accurate detail when used together
discuss the importance of validating and ground-truthing data provided by satellites. (optional).
The activity Interpreting observations from satellite images has strategies for helping students interpret images. It may be helpful for students to learn some of the strategies prior to doing this activity.
Download the Word file (see link below).
Related content
Real-life examples of validation and ground-truthing are found in these articles:
Related activity
Observation isn’t always straightforward. The activity Do you see what I see? explores concepts like reliability of observational information and replication and corroboration of data.
Acknowledgement
This resource has been produced with funding from the Ministry of Business, Innovation and Employment and the support of the New Zealand Space Agency.
Ministry of Business, Innovation and Employment and the New Zealand Space Agency
The New Zealand Space Agency, part of the Ministry of Business, Innovation and Employment, is the lead government agency for space policy, regulation and sector development.
