Proposal:Surface=laterite/Community

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Supporting subpage for Proposal:Surface=laterite. See also: Proposal:Surface=laterite/Science and Proposal:Surface=laterite/Data.

This page documents the community outreach, mapper responses, and background research history for Proposal:Surface=laterite. All mapper responses quoted below are from direct outreach conducted during the proposal draft process.

Prior work: background on surface=clay

The author of this proposal researched clay-textured tropical road soils and updated the surface=clay documentation to reflect that work.[1] At the time, making a formal proposal was not feasible. The updated surface=clay documentation acknowledged that iron-oxide-rich tropical soils were a distinct category but described them as a sub-case of clay rather than a separate value.

Subsequently, community arguments in favour of a dedicated laterite value prompted a much larger research effort. This included:

  • Full comparative analysis of five tropical road-soil types (documented in Proposal:Surface=laterite/Science)
  • Evaluation of three tagging approaches (Approach A: red-orange soils only; Approach B: all cohesive tropical soils; Approach C: iron-oxide-rich soil family)
  • Analysis of the bot migration history (documented in Proposal:Surface=laterite/Data)
  • Direct outreach to mappers across laterite-region countries

The research concluded that surface=laterite as a dedicated value under Approach C would gain broader support than extending surface=clay.

The working reference page produced by this research, User:Julcnx/Clay_textured_road_soils, is now redirected to Proposal:Surface=laterite/Science.

Outreach methodology

Direct outreach was conducted to 100 active mappers in laterite-region countries. Mappers were selected based on recent editing activity in confirmed laterite-region areas (Africa, Southeast Asia, Latin America, South Asia). The outreach message:

  • Described the proposed tag (surface=laterite) and its field criteria
  • Asked whether the description matched observed conditions in the respondent's mapping area
  • Asked for any regional names in use locally
  • Asked for photo contributions if available
  • Asked for any concerns or objections

41 responses were received at the time of proposal submission; 44 as of the RfC. Responses included positive confirmations, critical engagement, and cases where the respondent could not confirm due to remote-mapping-only workflows.

Community forum threads

Mapper responses

Confirmed field descriptions

Southeast Asia

  • Thailand, Cambodia: Multiple mappers in Southeast Asia confirmed that the field description (red-orange, firm/dusty when dry, plastic/sticky and slow-draining when wet) matches observed conditions.
  • Indonesia: A mapper with frequent on-the-ground experience in Indonesia confirms that tanah merah (literally "red soil") matches the field description: very dusty when dry, highly impassable when wet with adhesion to footwear described locally as "bélok". Notes that the OSM Wiki photo used for surface=dirt is not representative of tanah merah, whereas the Thailand motorcycle-wheel adhesion photo is recognised. Strongly supports the proposal.
  • Philippines: A mapper from the Philippines confirms that the field description matches: the surface is sticky, almost impassable when wet, and slow draining. Found mostly on mountainous and rugged terrain. Local terminology is "mud/clay" regardless of soil colour. The respondent notes that this material is distinct from the clay or mud of farms and rice fields: an intuitive local recognition that laterite-type soils and agricultural clay are different categories, even when the same vernacular label is applied to both.

Senegambia / West Africa

  • Regional name "rahnrahn" (Wolof) confirmed as a local name for laterite roads, alongside "piste" as a generic unpaved-track term.
  • Laterite roads in Senegambia tend to produce potholes rather than ruts; in both cases slow drainage and wet-season difficulty are characteristic.
  • Built-up laterite: in Senegambia and similar contexts, laterite is often imported from a borrow pit and laid on top of sandy or other subgrade soils rather than forming a natural surface. Where the material is natural laterite (not mechanically processed or bound), this is still surface=laterite; the material identity and wet-season behaviour are unchanged.

Colombia / Vichada

  • A mapper in Arauca (Colombia) described roads as yellow with small stones rather than red; Vichada roads matched the red description. The proposal's "usually red to orange-brown" range is correct; red is not a required condition. The term "trocha" was confirmed as a local term in Latin America for this road type.
  • A second independent Colombia confirmation describes beige/orange roads that become very slippery in rain, further supporting the colour range documented in the proposal.

French Guiana

  • A mapper active in French Guiana confirms that laterite surfaces are very common on minor roads and paths; the tag is more precise than surface=ground or surface=dirt. Positive confirmation.

Brazil (Mato Grosso)

  • Wet- and dry-season photos contributed. Positive confirmation.

Cambodia / Siem Reap

  • Positive ground-truth confirmation.

Kenya

  • A Kenya mapper (Nakuru County) confirmed the field description and points to Mapillary tracks and Google Street View as practical verification resources. Notes that rapid road development means some previously laterite roads may now be paved; mapping recency matters for surface tags in fast-developing areas.

South Africa / Kenya

  • A mapper with rural field and mapping experience in both South Africa and Kenya provides the first confirmed South Africa response. In Kenya, red iron-rich clayey soils from decomposed lava are used for informal unimproved roads: high clay content, goes plastic on first wetting, extremely slippery and slow to dry. In South Africa, red clayey soil from decomposed ancient sand dunes behaves similarly on informal roads, also extremely slippery when wet. In both countries, any road formalised by a layer of government involves adding crushed stone or low-clay soil gravel, sometimes lime-stabilised for heavier traffic: these correctly remain surface=compacted. The respondent confirms that in Kenya the local term is "Murram road" as a synonym for laterite, and that "nobody says Laterite". The South Africa local term is simply "dirt road". Photos from both countries offered.

India

  • A mapper with experience in parts of India confirms that the field description matches well: red-orange soil, firm and dusty when dry, sticky or difficult when wet, slow draining, with rutting. Local terms are "red soil road" or "mud road"; current mapping practice falls back to surface=dirt, surface=ground, or surface=clay. The respondent considers a dedicated surface=laterite tag valuable for improving consistency where the material is common. Note: as members of an organised editing team, they would refrain from voting on the proposal.
  • A second confirmation from Auroville (Tamil Nadu): the field description is accurate for the area. Local name is "Red Earth", directly corroborating the scope section entry for Tamil Nadu. Notes that rapid development means these roads are quickly disappearing in the area. Photos forthcoming.

Ghana

  • A mapper from Ghana confirms that "laterite" is the locally used term and that the material is recognisable on the ground. Notes that imagery mapping correctly falls back to surface=unpaved or surface=ground when the material cannot be confirmed. Their current practice of using surface=compacted where laterite has been quarried, imported, and engineered into a road surface is consistent with the proposal's distinction between natural laterite soil (surface=laterite) and processed laterite aggregate (surface=compacted). The respondent raises a valid concern that the proposal's length and number of edge cases may make the tag feel complex to apply; a streamlined version is in progress. Photos from Ghana contributed.

Cameroon

  • A mapper from Cameroon confirms support for the proposal and that "Laterite" is the locally used term. Raises a specific concern about the lead image (Thai laterite track photograph): it could be confused with exposed bare soil rather than a laterite road surface. Photos from Cameroon forthcoming. A photo showing characteristic road features in context (rut walls, a vehicle, cohesive cut banks) would be a stronger recognition anchor.
  • A soil engineer with direct Cameroon field experience confirmed that the description matches observed conditions and provided photos from Cameroon. This is the proposal's only academic field confirmation.

Madagascar (three independent respondents)

  • First respondent: ferralitic soils are the dominant soil type in Madagascar; most roads are unpaved. Local terms are "tany mena" (red earth) or simply "tany" (earth). Current mapping practice falls back to surface=dirt, surface=earth, or surface=unpaved. Photos to share.
  • Second respondent: active in rural areas, confirms red soil, dusty in dry season, muddy and sometimes impassable in the rainy season. "Laterite is a good description." Independent corroboration of the first respondent.
  • Third respondent: worked extensively in Madagascar with CartONG and the local OSM community, confirms surface=laterite as "perfect" for Madagascar roads. Unique field detail: on first wetting, the surface becomes so slippery that barefoot walking is impossible, directly corroborating the near-frictionless phase-1 wet description from a pedestrian angle. Notes surface=clay would also be acceptable as a fallback, but considers laterite more accurate. Flags CartONG and the local OSM Facebook community as contacts for further Malagasy mapper engagement.

Three independent respondents from Madagascar, nicknamed the "Red Island" for its lateritic soils, confirm the same field description.

Argentina (Misiones)

  • A mapper confirmed that the Misiones region has this type of surface and is sharing the proposal with the local mapping community there. Misiones is already represented in the examples gallery (Tierra colorada en Misiones); this response confirms the geographic scope and that local community outreach is in progress.

Bolivia

  • A mapper from OSM Bolivia confirms that the tropical region of Bolivia has reddish (lateritic) roads and considers the proposal very relevant. Consulting geologist colleagues for both scientific names and local vernacular terms.

West/Central Africa (French-speaking)

  • A French-speaking respondent confirmed in French that the field description matches observed conditions on the ground. Positive confirmation.

Germany (in Latin America context)

  • "Lehm-Piste" confirmed as German field usage for this road type.

Talk page observations

  • Visual recognition and routing signal: a community observer notes that laterite is recognisable from street-level imagery (citing GeoGuesser clips as an informal baseline), supporting the position that the material is visually distinct enough to warrant a dedicated tag. The same observer highlights the "impassable when freshly wet" characteristic as a signal that routing software could feasibly act on, independently reinforcing the routing implications section.

Critical and qualified responses

Imagery-first mapping barrier

Several respondents noted that they map primarily from satellite imagery and cannot confidently distinguish laterite from generic dirt without ground-level photos or local contacts. This confirms that surface=dirt must remain the default for remote mapping and that surface=laterite should only be applied with ground-level evidence. The proposal's surface=unpaved fallback for imagery-only mapping is consistent with this constraint.

A mapper who does not map from imagery but lacks technical expertise in road surfaces noted they default to surface=ground for all natural surfaces they cannot identify more specifically, calling the proposal "totally fine". This confirms that the fallback hierarchy already reflects existing mapper practice; surface=laterite adds a precise upper tier for mappers who can confirm the material. The same respondent suggested that a deep-learning-derived dataset estimating laterite extent from street-level imagery (analogous to existing paved/unpaved classifiers) could help mappers apply the tag more confidently.

"Laterite" is not universally known

Multiple respondents were unfamiliar with the term or did not use it locally. This is expected: as the proposal notes, the term is scientific rather than vernacular, and the field identification criteria are designed to make it accessible without geological expertise.

Similar-but-distinct soils (Cuba, civil engineering context)

A respondent in Cuba raised red ferralitic soils that share laterite's mechanical behaviour but are pedologically distinct. A civil engineer specialised in soil works raised a parallel concern: marl, silt, and clay road surfaces in other regions share wet-season plasticity and dry-season hardening. Red-Yellow Podzolic soils (Ultisols), which coexist with Oxisol laterite in regions such as Northern Thailand and cannot be separated without laboratory analysis, are explicitly in scope under the proposal. For other similar-behaviour soils outside the lateritic family, the "when uncertain, use surface=dirt or surface=ground" fallback hierarchy applies.

"Sable" (sand) in DR Congo

A mapper active in the Gungu and Matari areas (Kwilu and Kwango territories) reports that local contacts call laterite-looking road surfaces "sable" (sand), regardless of actual soil composition. This is a direct instance of the terminology gap the proposal addresses: local names diverge from both the scientific term and the observable material. The respondent notes that in data-scarce regions with unmapped roads, surface=dirt is the practical priority fallback; surface=laterite would apply in better-surveyed contexts. Field photos from 2018 Gungu territory available.

Clay/laterite conflation in the Philippines

A Philippines mapper reports that locally the surface is called "clay", and is consulting the DENR (Department of Environment and Natural Resources) for official soil classification. This is a real-world example of the clay/laterite conflation this proposal resolves: the Philippines has extensive lateritic soils, and the local default term "clay" currently maps to surface=clay.

Brown cohesive clay outside tropical context

A respondent confirmed firm-dusty dry and plastic-sticky wet behaviour matching the description, but reported colours between light and dark brown (not red/orange) and identified the material locally as "glina" (Slavic: clay). The non-red colour and non-tropical setting mean this soil does not meet the laterite criteria; surface=clay or surface=dirt is the appropriate tag. This case validates that the red/orange colour criterion is a meaningful differentiator: a plastic cohesive soil lacking iron-oxide colouring and outside the tropical belt belongs to surface=clay or surface=dirt, not surface=laterite.

Geological scope and verifiability (long-term Africa/Qatar mapper)

A mapper with long-term experience in Africa (unpaved roads graded from existing cover material) and Qatar (desert tracks) engages critically with the proposal. Key concerns:

  1. In their Africa experience, laterite was present in the road mix but not dominant, and roads were graded rather than engineered.
  2. The "-ite" suffix implies a mineral or rock, which conflicts with the soil usage the proposal targets.
  3. "Laterite" is used in varying and contested contexts in the geotechnical literature.
  4. Surface tags like surface=mud, surface=clay, and surface=sand are already used inconsistently, and adding a geologically-loaded term compounds that problem.

The respondent consistently uses surface=ground as a deliberately vague catch-all for Qatar desert tracks, because sand, rock, mud, and evaporites all collapse to a single observable fact (natural surface) and material-specific tags require more knowledge than is typically available.

Response: the note on "laterite" vs "lateritic" in the Science subpage addresses the suffix ambiguity. The broader concern that the term is contested in the literature is real and noted; the proposal's position is that OSM needs reproducible field criteria, not laboratory certainty, and that the observable indicators (tropical setting, red/orange colour, wet-season plasticity, cohesive profile) provide a usable proxy even where the pedological boundary is fuzzy. The "when uncertain, use surface=dirt or surface=ground" fallback directly addresses the constraint the respondent describes.

Massapê (Brazil)

One respondent listed both "terra roxa" and "Massapê" as local soil names. Terra roxa is in scope (latosol family). Massapê is a dark clay soil derived from gneiss and limestone, closer to a Vertisol; it belongs to surface=clay (rare edge case) or surface=dirt, not surface=laterite.

Cactolith geological variability concern

One respondent raised a concern about geological variability in regions where the same road surface term covers multiple soil types. This is noted as a valid edge-case concern; the proposal's field identification criteria are designed to be observable rather than geological-taxonomy-dependent.

Crisis and satellite-first mapping contexts

Several respondents confirmed that in crisis mapping or satellite-only workflows, the practical limit is paved vs unpaved, with local mappers filling in surface detail. This is consistent with the proposal: surface=dirt or surface=ground remain valid fallbacks when material cannot be confirmed on the ground, and surface=unpaved is the most accurate choice for imagery-only workflows.

Eurocentric gap

A respondent in the OSM LatAm community forum noted that the absence of a dedicated laterite surface value is an example of OSM's tag vocabulary reflecting European road types and infrastructure, leaving tropical road surfaces without precise representation. This framing is consistent with the broader motivation of the proposal.

Endorsements

  • Map_HeRo (post 40 of the clay discussion thread): explicit community endorsement for Approach C (iron-oxide-rich tropical soil family under surface=laterite).
  • Multiple mappers from Madagascar, Ghana, Cameroon, Kenya, and India with direct field experience: positive confirmation.
  • Soil engineer with Cameroon field experience: academic field confirmation.

See also

References

  1. ↑ OSM Community: surface=clay thread, post 38
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