Put camera phones to work for M&E
Photo-monitoring is a method of documenting and assessing visual changes in landscapes over time by repeatedly taking photographs from the same location. Aimed at sustainable land management researchers and practitioners, the method presented here uses photographs to track land-use changes in order to evaluate the progress and effectiveness of specific management practices. The user guide includes an overview of ground-based photo-monitoring, its capabilities and limitations and provides suggestions for those interested in adopting the methodology.
Not just How To, When to and Why to, too
In any situation, GBPM offers distinct advantages for assisting SLM initiatives in that:
- it uses readily available equipment and is relatively inexpensive, technically simple, and easily accessible by a wide variety of individuals;
- photographs are easily understood and provide opportunities for interpretation by scientists, practitioners, and local community members of any education level;
- when used with an appropriate analytical framework, changes in visual indicators can be linked to management goals and outcomes;
- photographs offer a visual base for group discussions of management plans and outcomes;
- photographs and their interpretations are easily communicated in public meetings, professional workshops and conferences, scientific publications, project reports, and outreach bulletins; and
- photographs can be integrated easily into existing or future GISs, such as Google Earth or ArcGIS.
The methodology is not without its limitations, however. Aside from the precision constraints presented by different technologies and equipment, GBPM and its resulting assessments may be limited in that:
- only changes that are visible and large enough to be recorded by a camera can be detected;
- changes in operators and equipment may affect results;
- representation of objects may be biased by the photographer or restricted by the image’s frame size or the number of images taken;
- while photographs can measure qualitative changes in an object’s number or size within the frame, they have limited accuracy for quantifying inventories within a landscape;
- external effects, such as season, time of day, and weather may cause photographs to suggest greater changes than have actually occurred; and
- photographs may not provide sufficient evidence of causal relationships in the object or variable of interest.
Examples from Yunnan, China and Tigray, Ethiopia