Maps will typically display one data variable or indicator, often using colour coding to indicate the density, frequency, or percentage in a given region, allowing quick comparison between regions. Colour coding can also be used to show changes over time (e.g. red for regions where an indicator got worse between two specific years, blue for areas where an improvement was seen and so on). Other information can be overlaid on the map, for example specific sites (e.g. hospitals or distribution centers) and text.
Maps can be static or interactive. Technical skills and software programs like Bespoke, Weave, and StatPlanet may be necessary to build interactive maps. However, simpler technology is available such as Microsoft’s MapPoint, which uses wizards to guide you through the customization stages. There are other cheaper low-tech options for static maps including overlaying information on maps in PowerPoint or customizing Google Maps.
GIS mapping is most useful when the data you wish to display has a strong regional or geographic dimension, or when regional patterns have changed over time. It can be a visually compelling way to explain decisions regarding the design and targeting of the program or project, for example in an inception or analytical report, or to display evaluation results. A lot of data can be displayed via a map, be sure that geographic context is meaningful to the use of the map; otherwise you may lead the viewer to unintended conclusions.
EPA Tracked Sites with Non-Grid Connected Wind Energy Generation Potential
This map shows sites with potential for wind energy production mapped atop average wind speed for the country. This map works well because it provides evidence for the potential development of wind-energy around the country.
GIS for disaster recovery
50 percent of the schools in Aceh were damaged or destroyed after the 2004 tsunami. GIS was used to discover where best to build, or not build, new schools based on population analysis and proximity to health facilities. An assessment of damaged facilities was also taken to identify which could be restored more quickly.
Advice for CHOOSING this option (tips and traps)
The following text is drawn from Guijt and Woodhill (2002)
“A GIS can help you collate, analyse and present information. Using GIS technology can generate maps representing a diversity of themes, able to combine quantitative and qualitative information. It can be a powerful communication mechanism for advocacy. It can also be useful for making simulations of possible designs.
However, GIS technology has been criticised for its quantitative, systematic, expert-centred and hi-tech approach, which distances stakeholders from the whole research and decision-making process. Nevertheless, if it is well organised, GIS use can be made more participatory by including stakeholders in the process of obtaining data, by presenting the images for their feedback and discussion, and to help stakeholders make their own management decisions. Various participatory options (e.g., discussion or mapping options) can be used to obtain these data.
Even if a GIS is used in a participatory process, there can be a loss of detail when attempting to enter descriptive information into a GIS programme. A GIS cannot always adequately represent qualitative information such as social, economic and environmental explanations of a problem obtained at the village level.” Guijt and Woodhill (2002)
Advice for USING this option (tips and traps)
Ensure you have the training and expertise to implement this option.
Be clear that the evaluation has need and the budget for this option. GIS is particularly useful and important in particular contexts: for example rebuilding post emergency and planning for land-use. Consider how important it is to involve community in the use of the tool and if so, that the evaluation team factor this into their design.
Classification of Data: for more on when to use different groupings of data for geographic mapping.
More than a Pretty Picture: Using Poverty Maps to Design Better Policies and Interventions: detailed guidance on the use of Small Area Estimation poverty maps in research and policy making.
How to Make a US County Thematic Map Using Free Tools: a fairly technical guide from Flowing Data on how to make choropleth maps for free.
Faster Choropleth Maps with Microsoft Excel: a fairly technical guide on how to make choropleth maps in Excel (requires use of VBA code).
Google Fusion Tables: free online tool for visualising data in map form.
How to use Microsoft MapPoint: these pages demonstrate how to use MapPoint to its full capabilities. Each function and feature is described, along with caveats and potential problems.
StatPlanet: free online mapmaker.
OIC Weave: another free online mapmaker.
Ushahidi Tool: Ushahidi Tool is a "free and open source mapping and content management system which can be used by organizations worldwide in crisis-related situations.
OnTheMap: a US Census Bureau tool to map geographic data.
The risks of using choropleth maps: a good read on the risk of using choropleth maps, written by Patricia Rogers.
ESRI, (2007). GIS for disaster recovery. Retrieved from website: http://www.esri.com/library/brochures/pdfs/gis-for-disaster-recovery.pdf
Guijt, I. and J. Woodhill (2002). Managing for Impact in Rural Development : A guide for project M & E. Rome, Italy: International Fund for Agricultural Development http://www.ifad.org/evaluation/guide/index.htm
Bedi, T., Coudouel, A., & Simler, K., (Eds). The World Bank, (2007). More than a pretty picture : using poverty maps to design better policies and interventions. Retrieved from website: http://siteresources.worldbank.org/INTPGI/Resources/342674-1092157888460/493860-1192739384563/More_Than_a_Pretty_Picture_ebook.pdf