The Pedagogical Benefits of Participatory GIS for Geographic Education

In this article, participatory GIS (PGIS) is explored and established as a powerful platform for geographic education. PGIS pedagogy can help educators meet diverse learning objectives pertaining to: (1) local knowledge and place-based thinking; (2) community engagement; (3) field mapping with geospatial technologies; (4) mixed-methods research; and (5) fostering of critical reflexivity in students. The discussion is supported with insights from multiple student-facilitated PGIS projects organized in rural Tanzania. There also is a thorough discussion of the challenges and caveats associated with involving students in PGIS projects, and a call for new research for assessing and advancing PGIS pedagogy.     

Analysis of gravity gradients over a thin infinite sheet

Expressions are derived for the horizontal and vertical gradients of the gravity anomaly over a thin dipping sheet of infinite depth extent. The resultant of these two gradients, known as the complex gradient, is also derived and properties of the amplitude and phase responses of the complex gradient are studied. It is shown that the amplitude plot is a symmetric curve whose, shape is independent of the dip (?) of the sheet whereas the phase plot is an antisymmetric curve with an offset value equal to ?-π/2. The depth to top of the sheet is obtained from the amplitude plot. The method is applied on a field example and the results are in good agreement with the results obtained by earlier workers.