US terrain screening with native USGS elevation.

USGS 3DEP project-level 1 m data

The pilot reads bounded windows from verified USGS 3DEP project-level 1 m GeoTIFFs. It does not download entire regional rasters or process raw point clouds. The source project, dates, horizontal CRS, NAVD88 height reference and raster alignment are recorded.

Native 1 m grid spacing is not a promise of 1 m survey accuracy, nationwide availability, current ground conditions or a 25 cm product. Newer candidate files may contain NoData; usable project selection and its dates are disclosed.

Draw the area you intend to study

Find a general location with Census address search or navigate the map, then draw and confirm an area. Feet/acres and metric display are available; calculations and CSV columns retain explicit metric units.

The default study buffer is 250 m. The four-million-cell, one-worker, 120-second and memory limits apply. Large or uncovered requests fail explicitly.

Optional soil information is a separate source

USDA SSURGO soil information is off by default. If you enable it, the drawn polygon is sent to USDA Soil Data Access. Regional map units and source component proportions do not establish site infiltration or foundation conditions.

FEMA flood information is separate from terrain screening. No verified live flood adapter or flood-depth prediction is offered.

What terrain screening cannot determine

Terrain screening does not simulate rainfall, infiltration, sewer capacity or the hydraulic effects of walls and culverts. It cannot predict flood depth, size a drainage system or confirm that a property is safe to build on.

A local catchment is limited to the analysed area. Contributions from beyond its boundary can be unknown. A modelled boundary crossing is not evidence of a real drain or drainage outlet.

Common questions