Mapping Ice Melt Extent in Greenland between 1979-2007 Using ArcGIS
This activity introduces students to Greenland ice-melt data derived from passive microwave remote sensing between the years 1979 and 2007. Students make a quantitative comparison between the two years using the mapping program ArcGIS. Students are provided with NASA raster images in GeoTiff form that show Greenland ice melt extent over two of the years on record (1979 ad 2007). Students then draw polygons over these raster files and calculate a change in area between the years on record. While tools exist in ArcGIS to quantify the extent of ice melt using the raster images themselves, drawing polygons is an important and often little-practiced skill in ArcGIS, and is therefore the focus of this activity. This activity can also be modified for more advanced map-makers working with raster files, who need practice using additional tools in the Arc Toolbox. However, raster calculations are not generally a skill covered in an introductory GIS course.
The activity is meant to reinforce important map-making skills (like drawing polygons and creating new geodatabases) using a data set that explores a real-world application of ArcGIS for Earth Science students. While any two (or more!) years on record can be used, 1979 and 2007 have been used to explore extremes in the data. You can learn more about the data set and the GeoTiff images here: http://nsidc.org/greenland-today/. The activity was designed for students with prior mapping skills, but can be modified for those who have little to no mapping experience (step by step instructions can be provided, upon request).
Skills and concepts that students must have mastered
How the activity is situated in the course
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Higher order thinking skills goals for this activity
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Description and Teaching Materials
This activity should be done independently and could take anywhere from 2-4 hours to complete, depending on student skill level and speed.
Students are first asked to read the introduction to the worksheet and explore the website from which the data is found. Students then download all appropriate data and proceed with the activity as stated on the activity worksheet, depending on their skill level.
When completed, students should have a PDF of each map they created, as well as a calculation for how much sea ice extent has changed over the last 40 years. To make the analysis more advanced, students can report their ice sheet cover and a class average can be calculated and compared to recent scientific analysis on the Greenland Ice Sheet (http://nsidc.org/greenland-today/). An analysis of why the class estimates may differ from the NASA estimates would help solidify understanding of the limitations of drawing polygons when mapping. If students are more advanced, they can then practice the same activity using the rasters provided and compare their polygon calculations to the raster calculations.Student Handout (Microsoft Word 2007 (.docx) 153kB Sep12 18)
Mapping Materials (Zip Archive 283kB Sep12 18)
Teaching Notes and Tips
This mapping activity is meant to address a unique and targeted skill in GIS mapping software, rather than to accurately depict ice melt extent through time. Students are meant to draw parallels between skills learned in a mapping course and their relationship to real world applications.
(Please note: there are no step by step instructions on how to draw polygons, etc in ArcGIS. If you require additional instructions for your students, please contact the author of this assignment using the contact details on the SERC website).