Choose the Question the Map Can Help Answer
A map can help a team locate an information gap, compare broad planning areas or understand a modeled scenario. It cannot answer every question about next week's weather, a particular household or permission to travel. First write the decision you need to support. Then check whether the map's purpose matches it.
UNDRR's exposure definition concerns people and tangible assets situated in hazard-prone areas. A map may represent only some of them. A flood-hazard layer is not automatically a full assessment of vulnerability, capacity or need.
Read the Map in a Reproducible Order
- Identify the product. Record publisher, title, version, issue date, geographic coverage and the original legend. Establish whether it depicts observed events, modeled hazard, exposure, combined risk or something else. If a screenshot has lost its legend or source, retrieve the original before interpreting its colors.
- Read the scenario and time reference. Find the period of input data and the event, likelihood or assumptions represented. A publication date is not necessarily the date of the underlying measurements. Do not turn a long-term likelihood into a prediction for one day.
- Check scale and resolution. Identify the smallest unit the product meaningfully represents and any boundary or location uncertainty the publisher describes. Zooming into a broad layer does not create new building-level evidence. A fine-looking basemap does not improve the underlying model.
- Ask what is excluded. Look for omitted hazards, missing areas, unrecorded settlements, dated population information, protection assumptions and infrastructure dependencies. “No data” and “low modeled likelihood” are different statements.
- Compare with the decision. Decide which part of your question the map supports and which evidence is still required. Current conditions need current authorized information; individual assistance decisions need their actual criteria and appropriate household evidence.
- Record the bounded conclusion. Keep the map reference, supported observation, major uncertainty, proposed follow-up and responsible role. Share only the detail appropriate for that audience; do not circulate sensitive household locations to make a planning illustration more precise.
Work Through a Complete Fictional Example
All Riverbend records below are invented for practice. None is a real map or forecast.
| Item | Supplied Facts |
|---|---|
| M1 | A district planning map issued in March 2024 using a 2022 river model and 2023 building footprints. |
| Legend | Shading depicts modeled river inundation for the named planning scenario. The product is supplied at 1:50,000 for district planning. It contains no household vulnerability data. |
| Coverage | The legend excludes surface-water drainage flooding. Informal riverside structures added after the footprint survey are not represented. |
| Measure assumption | M1 models the area before a proposed barrier. No model update showing that barrier is supplied. |
| Service question | A clinic coordinator needs to identify which service-access questions to discuss with the district team before the wet season. |
| Current information | The team has no current forecast, inspection, route assessment or household assistance assessment in this packet. |
The clinic and East block appear within M1's shaded area. West block appears outside it, but the road serving West crosses the shaded area. The team proposes: “Use M1 to identify the clinic, East block and the shared road as planning follow-up locations. Ask the mapping owner about the model, missing structures and current available layers. Ask the service and local technical owners about current access and continuity arrangements.”
That conclusion stays within the packet. It does not estimate a number of affected households, say a flood will occur next week, or exclude West residents from support. It also does not claim that West is safe: the map omits a hazard pathway and household conditions, and its road connection raises another question.
Repair the Plausible but Unsupported Conclusion
An initial draft says: “All East households will flood next week; West needs no assistance because it is outside the red area. The new barrier makes the clinic safe.”
Three separate repairs are needed. M1 supplies a planning scenario, not next week's forecast. Its shade is not a household needs assessment or eligibility rule. Its pre-barrier model cannot establish how the proposed measure changes risk. Retain the service-access planning question while removing all three claims.
The revised note could read: “M1 places the clinic, East block and part of West's access road within its modeled river-inundation area. Its older building layer omits some structures, and it does not assess surface-water flooding or household circumstances. The coordinator will seek updated mapping and current technical advice before making service decisions. Household assistance questions require their own assessment.”
Recognize a Different Product
An official service may deliberately answer a narrower question. For example, England's long-term flood-risk service describes area risk and explicitly excludes an individual-property likelihood estimate and some flooding sources. Its separate current flooding service provides warnings, levels and a short-term outlook. These England-specific services illustrate the difference between products; their categories or procedures are not rules for Riverbend or another country.
If you are instead reading a real event map, distinguish observed coverage from places not assessed and record when observations were made. If you are reading a forecast map, preserve its validity period and stated uncertainty. Neither label allows you to infer information the publisher did not provide.
For terminology, use hazard, exposure, vulnerability and capacity. For the separate implications of a measure, use residual risk. Operational and safety decisions remain with the authorized local roles using current information.