Question: Do map symbols convey hazard or danger clearly when needed? Are hazardous or dangerous areas clearly indicated with a graphic or pictorial icon, warning color, or other symbol that could be interpreted as hazard or danger? If you are unsure how to evaluate the question above, consider the following methods of evaluation:

Method 1: Self evaluation

• Identify current map symbols that represent hazards on your organisation's maps.
• Answer the following question: Does each individual symbol's color/icon imply hazard or danger across all common cultural norms for the intended map audience?

Method 2: Individual map user evaluation

• Show each map symbol to individual map users, either in map context or isolated as the symbol itself.
• Ask each map user what he/she believes each symbol represents, and if (in their opinion) if it adequately conveys danger/hazard (Yes) or not (No).
• Tally results for each symbol that has been assessed as percentage of symbols with "Yes" answers.
• Modify or redesign any symbols with low percentages of "Yes" answers.

Method 3: Group evaluation

• Select a small group of map users (5-8 people) and assemble them into a focus group.
• Show each map symbol to the focus group, either in map context or isolated as the symbol itself.
• Ask the focus group the following question for discussion: Does each individual symbol's color/icon imply hazard or danger across all common cultural norms for the intended map audience?
• Identify common trends in the discussion.
• Modify or redesign any symbols in cases where there is no strong agreement to the question listed above.

Example 1: The map symbols in (C) were developed for humanitarian demining (landmine clearance). The skull and crossbones symbol and red triangle, international standard symbols used in demining to mark the perimeter of a minefield on signs (A and B), are incorporated into the map symbols.

Example 2: Hazard symbols for humanitarian demining in a map context.

Use pictorial or iconic symbols to replicate or represent the hazard to quickly convey to map users that danger is present. Pictorial or iconic symbols are particularly useful for the general public or novice map users, and for maps that may span several language or cultural groups.

Here are some additional resources to help improve your map:

1. The Noun Project is a collection of millions of icons, many of which may be used for mapping purposes and viewed here.
2. The United Nations Office for the Coordination of Humanitarian Affairs (UNOCHA) has developed a set of humanitarian icons with many pictorial symbols for hazards which can be adopted and viewed here.
3. The U.S. Department of Homeland Security (DHS) has developed emergency management symbols with many many pictorial symbols for hazards which can be adopted and viewed here.
4. Detailed instructions for how pictorial symbols were designed for hazards in humanitarian demining (landmine removal) can be viewed here.

Question: Are map symbols intuitive, considering the range of map users (differences in background, culture, education, etc.)? If you are unsure how to evaluate the question above, consider the following methods of evaluation:

Method 1: Self evaluation

• Identify all current map symbols that represent hazards on your organization's maps.
• Answer the following question: Is each symbol intuitive across all common cultural norms for the intended map audience? Could any symbols be interpreted differently by different map audiences?

Method 2: Individual map user evaluation

• Show each map symbol to individual map users, either in map context or isolated as the symbol itself.
• Ask each map user to identify what he/she believes each symbol represents.
• Tally all combinations of results for each symbol. Identify any symbols that have several different responses. These are likely symbols that are not designed clearly or may have multiple meanings to different map audiences.
• Modify or redesign any symbols with low agreement on meaning.

Method 3: Group evaluation

• Select a small group of map users (5-8 people) and assemble them into a focus group.
• Show each map symbol to the focus group, either in map context or isolated as the symbol itself.
• Ask the focus group the following question for discussion: What do you think each symbol respresents? Are there any cultural norms that might result in confusion of a symbol's meaning?
• Identify common trends in the discussion.
• Modify or redesign any symbols in cases where there is no strong agreement for symbol meaning.

Example 1: Iconic or pictorial symbols often can be used to ensure that symbols are intuitive to map users. Examples of iconic or pictorial map symbols for point symbols are displayed below for different types of landmine clearance processes (A, B, D) and a landmine victim (C).

Example 2: The map displayed here by the United Nations Organisation for the Coordination of Humanitarian Affairs (UNOCHA) uses several intuitive, iconic map symbols.

Source: UNOCHA and Relief Web (http://reliefweb.int/map/sudan/sudan-darfur-new-displacement-2015-05-february-2015)

Example 3: Symbols may have specific meanings in some cultures.

The map symbol above is commonly used to represent hospitals on maps in the United States. However, the letter "H" does not convey hospital in every language.

Depending on the culture, symbol color, and context of the map, this cross symbol could mean the presence of a medical facility or a place of worship.

Example 4: Iconic or pictorial symbols may have limitations for distinguishing between related features.

The symbols above are similar in appearance, but have slightly different meanings: storm surge (left) and tsunami (right). Although the general meaning (coastal hazard) may be inferred from both symbols, it may be less clear as to the specific difference between both.

Source: UNOCHA (http://reliefweb.int/report/world/world-humanitarian-and-country-icons-2012)

Use pictorial or iconic symbols as much as possible to ensure that symbols are intuitive and easy to understand for all map users. Pictorial or iconic symbols are particularly useful for the general public or novice map users, and for maps that may span several language or cultural groups. If the map needs to be interpreted by people who do not speak the same language, then try and avoid non-iconic, geometric symbols (e.g., circles, squares, triangles) because the symbol may not make sense if the user is not able to read the legend.

Here are some additional resources to help improve your map:

1. The United Nations Office for the Coordination of Humanitarian Affairs (UNOCHA) has developed a set of humanitarian icons with many pictorial symbols for hazards which can be viewed here.
2. The Noun Project is a collection of millions of icons, many of which may be used for mapping purposes and may be viewed here.
3. The U.S. Department of Homeland Security (DHS) has developed emergency management symbols with many many pictorial symbols for hazards which can be adopted and viewed here.
4. Detailed instructions for how pictorial symbols were designed for hazards in humanitarian demining (landmine removal) may be viewed here.

Question: For hazards, is the extent of the hazard represented accurately according to the scale of the map? Should the hazard be represented as a point, line, or polygon (area)? Do point, line, and polygon (area) symbols for the same feature appear similar to each other?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• First, determine the minimum and maximum scales on the maps that the map symbols should support (e.g., maps ranging from 1:10,000 (minimum scale) to 1:100,000 (maximum scale)).

• Next, evaluate all symbols displayed at each of these minimum and maximum scales. Consider the following:

  • Are symbols legible and readable at both the minimum and maximum scales?
  • Are symbols too crowded and do they overlap too much at the maximum scale?
  • To be more precise, should point symbols appear as areas/polygons as the scale changes from the minimum scale to the maximum scale (see Example 1)?

• Finally, consider designing two or three symbols for each feature for the different ranges in map scale (see example above). Keep in mind that symbols for the minimum scale can be more complex (E.g., point symbols with icons, or area/polygon symbols).

Example 1. A minefield might be represented as a point on one scale, but as a polygon (area) at a larger scale as the map "zooms in." In the example below, minefields are represented as red triangles for the sake of simplicity at a small scale (large geographic area). As the scale becomes larger or "zooms in," an icon is added to the symbol. At the largest scale, the point symbol changes to a polygon symbol to depict the actual perimeter of the minefield.

For maps displayed at a range of scales, design multiple symbols for the same feature, each symbol for a general scale range.

Here are some additional resources to help improve your map:

1. Detailed instructions for how map symbols at different scales were designed for humanitarian demining can be downloaded here.
2. Scale Master is a tool that may be used to develop symbols at multiple scales. Scale Master is available here.

Question: If symbols need to show complex information, do the symbols relate in a logical manner from a simple (general) to more complex (specific) structure?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• First, group related symbols into general categories. (E.g., "Hazards," "Critical Facilities," "Infrastructure," etc.)
• Next, list the name of each feature that requires a symbol on a note card, and then arrange the cards into groups of symbols that are related.
• Finally, once these general categories are developed, evaluate the similarity of the symbols in each category. (For example, do symbols relate to each other graphically? Are graphics such as shapes or colors used to group similar symbols in a logical manner?)

Example 1. Humanitarian demining maps are used for a range of purposes and audiences. Maps are created for the general public, donors, and operations personnel. Depending on the level of information needed for each map, a hierarchical or tiered structure to the symbols can provide flexibility for selecting either general or specific information to show on the map. The example here shows a tiered structure for a minefield symbol, which might be depicted simply as a "Hazard" for general audiences, but also as a "Mined Area" that has an "Active Status" for demining operations personnel. The red triangle is the base graphic for the symbol, and as the level of complexity increases for the symbol as additional graphic attributes for the symbol are added.

Design symbols with a hierarchical or tiered organization.

Here are some additional resources to help improve your map:

1. Example of tiered or hierarchical symbols designed for the U.S. Department of Homeland Security (DHS) can be viewed here.
2. Detailed instructions for how tiered or hierarchical map symbols were designed to display different levels of information complexity for humanitarian demining can be found here.

Question: Is there uncertainty in the data source, and if so, should map symbols display uncertainty of information or data quality when needed? Or, is it not necessary to show uncertainty information to map users?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• Design a focus group with typical map users.
• Ask each map user about different types of uncertainty and inventory the various types of uncertainty that may be present in the data.
• Ask each map user whether or not displaying uncertainty on the map is necessary for accurate interpretation of the map. Does displaying uncertainty convey important information to the map user, or does it cause confusion for map users that hinders interpretation of the map?
• Following the focus group, develop graphical methods for displaying uncertainty, if appropriate.

Example 1: The map displayed here by the United Nations Organization for the Coordination of Humanitarian Affairs (UNOCHA) displays the total number of internally displaced persons (IDPs) that have moved into different IDP camps in Sudan. Note how the color green is used to display the number of IDPs that are verified(more certain) and the color orange is used to display reported by not verified (more uncertain) numbers of IDPs.

Source: UNOCHA and Relief Web (http://reliefweb.int/map/sudan/sudan-darfur-new-displacement-2015-05-february-2015)

Example 2: Uncertainty is especially common in crisis mapping for maps that forecast or predict hazards or risks. The map below displays a projection of future sea level rise (6 meters) in a coastal area of Maine (United States of America). Such predictions for the sea level rise are approximate and not exact due to several factors. The map displays three different approaches: no uncertainty is displayed (A), uncertainty is conveyed through a "fuzzy" border (B), and two other scenarios (5 meters and 7 meters) are displayed to convey to map users the differences between a +/-1 meter scenarios (C).

Determine what type(s) of uncertainty may be present in the map and decide whether it is appropriate to symbolize that uncertainty or not.

Here are some additional resources and examples to help improve your map:

1. NOAA's Sea Level Rise Viewer, which has options for symbolizing confidence levels of sea level rise predictions on an interactive map.
2. See Chapter 23 "Visualizing Uncertainty" in Thematic Cartography and Geovisualization, 2008, 3rd edition, by T.A. Slocum, R.B. McMaster, F. Kessler, and H. Howard, Prentice Hall.

Question: Do symbols adhere to existing standards? Will maps be shared with other organisations, and if so, are common map symbols used by both organisations?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• Identify if any map symbol standards exist in a specific mapping domain.
• Remember that standards may exist within an organisation or across several organisations.
• Determine if your organisation's symbols adhere to these standards or not by comparing the visual appearance of individual symbols.
• Consider adopting standardised symbols, if available and if appropriate.

Example 1: The maps displayed here were created by two different organisations. One map is by ESRI which displays the 2015 earthquake in Nepal. The other map is by the United Nations Organisation for the Coordination of Humanitarian Affairs (UNOCHA) and displays refugee displacements in Sudan. Although created by separate organisations, the symbols used on both maps are similar. A benefit of similar symbols is that that map users can learn the meaning of one symbol set, and the symbols do not need to be changed if both organisations were to share maps or data. Both maps use the Humanitarian and Country Icons 2012 symbol set designed by UNOCHA, also displayed here.

Source: http://story.maps.arcgis.com/apps/MapSeries/?appid=34934c03445649cd9fcb422a2a7279c7

Source: UNOCHA and Relief Web (http://reliefweb.int/map/sudan/sudan-darfur-new-displacement-2015-05-february-2015)

Source: UNOCHA and Relief Web (http://reliefweb.int/report/world/world-humanitarian-and-country-icons-2012)

Adopt standardized symbols as much as possible to increase efficiency. When standardized symbols do not exist, consider proposing a new standard.

Here are some additional resources to help improve your map:

1. Symbol Store, a map symbols sharing tool.
2. Discussion about how standardised map symbols were developed for humanitarian demining can be downloaded here.

Question: Are symbols at the top of the map's visual hierarchy?

If you are unsure how to evaluate the question above, consider the following method of evaluation: * Choose a small number (5 or so) of symbols on the map. Develop a question for each map symbol that will require map users to interpret the meaning of each symbol. For example, this might include the following question for the map example displayed above: "How many malaria outbreaks were reported at location X?" * Tally correct answers for the group of symbols that have been assessed, which will be an accuracy assessment. If the accuracy assessment displays a trend for several incorrect answers, it could be a sign that map users are misinterpreting map symbols, possibly as a result of poor figure/ground. * Consider modifying or redesigning symbols with low accuracy rates.

Example 1: The map displayed here is poorly designed as symbols are obscured by other features on the map and are difficult to decipher. Here the symbols do not emerge prominently as a figure as they should. Other features on the map detract from the data that is displayed for the number of malaria outbreaks.

Example 2: This version of the same map is much improved as symbols are a figure that are easy to find by the map user. The symbols (green circles) contrast nicely with the background (yellow). The design of other map elements (legend, title, scale) is much improved as well, along with the size and positioning of the actual mapped area.

Modify any symbols that do not emerge at the top of the map's visual hierarchy, or where figure/ground is poor or not established correctly.

Here are some examples of resources with suggestions for how to develop an effective visual hierarchy:

1. See Chapter 12 in Thematic Cartography and Geovisualization, 2008, 3rd edition, by T.A. Slocum, R.B. McMaster, F. Kessler, and H. Howard, Prentice Hall.
2. See Cartography., 2018, by Kenneth Field, ESRI Press.
3. See Designing Better Maps: A Sourcebook for GIS Users, 2nd edition, 2016, by C.A. Brewer, ESRI Press.
4. See Designed Maps: A Sourcebook for GIS Users, 2005, by C.A. Brewer, ESRI Press.

Question: Is it easy to tell the difference between different symbols? If using color as a symbol, are colors ordered logically and are the colors easy to distinguish between? If using icons, are icons easy to differentiate? If size is used, is it easy to tell the difference between the size of symbols?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• Choose a small number (5 or so) of symbols on the map. Develop a question for each map symbol that will require map users to interpret the meaning of each symbol. For example, this might include the following question for the map example displayed above: "How many malaria outbreaks were reported at location X?"
• Tally correct answers for the group of symbols that have been assessed, which will be an accuracy assessment. If the accuracy assessment displays a trend for several incorrect answers, it could be a sign that map users are misinterpreting map symbols, possibly as a result of poor figure/ground on the map. Consider modifying or redesigning symbols with low accuracy rates.

Example 1: The maps here show flood risk for a region of interest. The map on the left is poor because the colors are not ordered logically in a way that is easy to understand for map users. The map on the right is an improvement because there is a logical sequence to the blue color scheme (dark blue - high risk; medium blue - moderate risk; light blue - low risk).

Example 2: When using symbols that are sized differently, make sure they are not too similar in size. The two maps here display the same data, but the sizes of the symbols on the map on the left are very similar, making the map difficulty to interpret by map readers. The map on the right is improvement because the sizes of the map symbols contrast with each other. Be sure to always choose symbols that are easy to distinguish from one another.

Develop symbols that are easy to distinguish between as much as possible.

Here are some additional resources to help improve your map:

1. Color Brewer, an online color selection tool for maps, provides excellent examples of color schemes that provide adequate contrast. Color Brewer may be found here.
2. Adobe Color Wheel is an excellent online tool that allows users to generate custom color palettes. Adobe Color Wheel may be found here.

Question: When map symbols are printed or photocopied in black and white, is the meaning of each symbol preserved and do the symbols still contrast with each other?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• Print or photocopy map symbols in black and white and then compare to symbols printed in color.
• Determine any differences in the visible appearance of symbols that are lost without the use of color.
• Redesign any symbols that do not reproduce well in black and white.
• Consider using graphical attributes other than color (patterns, textures, shapes, line styles, etc.) in the redesign process.

Example 1: A map might need to be printed or photocopied in a field office where only black and white printing or photocopying is available. In the example here, the color map (left) is difficult to interpret when printed or photocopied in black and white (right).

Example 2: Although the symbols on the map displayed here use color (left), they are also reproducible in black and white (right) with no loss of information. Icons and borders around the symbol reproduce well in both color and black and white.

Develop symbols that can be distinguished between as much as possible when printed or photocopied in black and white.

Here are some resources that may be helpful for designing symbols that reproduce in black and white:

ColorBrewer is a free online tool that is helpful for selecting color schemes for maps, and has an option to view color schemes that are black and white print friendly. Color Brewer may be found here.

Question: Are map symbols friendly for mobile devices (tablets, phones) if maps are required for display on these devices?

If you are unsure how to evaluate the question above, consider the following method of evaluation:

• View map symbols on a variety of mobile devices (phones, tablets) with various screen resolutions and under various lighting conditions.
• Symbols that are illegible or are hard to see clearly should be considered for redesign to ensure that they meet the minimum requirements of typical mobile devices that are used for map viewing.

Example 1: The map symbols below are sized large enough for easy display on mobile devices as the map zooms in and out. Appropriate colors are selected to contrast with the light gray basemap.

Use map symbols that are easy to read, distinguish between, and contrast with basemaps if maps are developed for mobile devices.

Here are some resources that may be helpful for designing symbols for mobile devices:

1. Guidelines for designing icons for Google Android devices be found here. Additional icon design guidelines may be found here.

2. Guidelines for designing icons for Apple devices be found here. Additional icon design guidelines may be found here.

3. See the extended abstract entitled "Designing Map Symbols for Mobile Devices: Challenges, Best Practices, and the Utilization of Skeuomorphism" by J.E. Stevens, A.C. Robinson, and A.M. MacEachren which is available here.