---
title: "Calculate Tia Topographic Factors"
method: POST
path: "/v1/site/tia/topographic-factors/calculate"
tags: ["site/tia"]
---

# Calculate Tia Topographic Factors

`POST /v1/site/tia/topographic-factors/calculate`

## Request

- Base URL: `https://api.shapemaker.io` (the document declares no server; this is the origin it was published from)
- URL: `https://api.shapemaker.io/v1/site/tia/topographic-factors/calculate`
- Auth: OAuth 2
  - Password
  - Token URL: `/v1/auth`

Calculate topographic factors K_zt for multiple wind directions.

This is a standalone calculation endpoint that doesn't require a structure.
Takes directional data (exposure category and optional topography per direction)
and returns the topographic factor for each direction.

## Request body

- TiaTopographicFactorsInput
  - `elevationM` number, required: Elevation above ground in meters
  - `directionalData` TiaDirectionalDataInput[], required: List of directional data (exposure category and topography per direction)
    - `globalWindDirection` number, required: Global wind direction in degrees
    - `exposureCategory` 'B' | 'C' | 'D', required
    - `topographyData` SiteOrographyInput
      - `feature` 'flat' | 'ft_hill' | 'hill' | 'ft_ridge' | 'ridge' | 'rolling_ridge' | 'rolling_hill' | 'escarpment' | 'na', required
      - `H` number, required
      - `X` number, required
      - `L_up` number, required
      - `L_down` number, nullable, required
      - `construction_points` ConstructionPointsEntityInput
        - `upwind_slope` SlopeConstructionPointsEntity
          - `point_A` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_B` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_C` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_D` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_E` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
        - `downwind_slope` SlopeConstructionPointsEntity
          - `point_A` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_B` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_C` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_D` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required
          - `point_E` TerrainProfilePointEntity
            - `point_index` integer, nullable
            - `distance_from_start_m` number, required
            - `altitude_m` number, required

## Response `200`

Successful Response

- TopographicFactorOnElevationView[]
  - `elevationM` number, required: Elevation above ground in meters
  - `globalWindDirection` number, required: Global wind direction in degrees
  - `topographicFactor` number, required: Topographic factor (Kzt) at the given elevation

## Other responses

- `422`: Validation Error

---

[API](https://skmtc.dev/shapemaker/apis/shapemaker-api.md) - [All operations](https://skmtc.dev/shapemaker/apis/shapemaker-api/llms.txt) - [OpenAPI document](https://skmtc.dev/shapemaker/apis/shapemaker-api/revisions/b8461cf1236c?raw)