Tsunami workflows often need different zones for mapped exposure and
for finding a meaningful inland exit.
prepare_tsunami_zones() makes those roles explicit.
Three spatial roles
| Object | Role | Used for | Common mistake avoided |
|---|---|---|---|
| Land-only hazard zone | Origin and mapped-output area | Road origins and final time outputs | Mapping through water or starting origins offshore |
| Water-combined escape zone | Meaningful inland exit context | Avoiding coastline exits | Treating the shoreline as an automatic safety boundary |
| Road-aware escape boundary | Road-preserving exit-detection boundary | Finding candidate safety exits | Dropping bridge, causeway, or walkway connections |
The water-combined escape zone is a processing layer, so it is not shown as a separate planning boundary in this compact map. Its role is to prevent a land-water split from creating artificial coastline exits.
Prepare the zones
zones <- prepare_tsunami_zones(
inundation = inundation,
dem = dem,
target_crs = "EPSG:32748",
inundation_threshold = 0,
dem_sign_multiplier = 1
)
roads_for_escape <- crop_roads_to_inner_extent(
roads = roads,
zone = zones$escape_zone,
inset_x_m = 250,
inset_y_m = 250
)
escape_boundary_zone <- make_road_aware_escape_zone(
escape_zone = zones$escape_zone,
roads = roads_for_escape,
road_buffer_m = 2,
crop_buffer_m = 3
)Model travel to safety
result <- run_evacpath(
hazard_zone = zones$hazard_zone,
escape_zone = zones$escape_zone,
roads = roads,
roads_for_escape = roads_for_escape,
dem = zones$dem,
target_crs = "EPSG:32748",
road_aware_escape_zone = TRUE,
escape_zone_road_buffer_m = 2,
escape_zone_crop_buffer_m = 3
)
| Modeled output | Example value |
|---|---|
| Minimum modeled time (minutes) | 0.31 |
| Median modeled time (minutes) | 10.09 |
| Mean modeled time (minutes) | 9.65 |
| Maximum modeled time (minutes) | 22.84 |
| Origins | 40.00 |
| Destinations | 12.00 |
| Walking speed (m/s) | 1.22 |
Inspect the local hazard boundary, road network, elevation sign convention, and projected CRS before relying on candidate escape points or modeled times.