> ## Documentation Index
> Fetch the complete documentation index at: https://calcs.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# GIS Solvers

> Overview of Geographic Information System solvers available in Calcs.com

GIS (Geographic Information System) solvers integrate external geographic and geospatial data sources to provide location-specific engineering parameters for calculations.

## Available GIS Solvers

<CardGroup cols={2}>
  <Card title="Orography Solver" href="/calcs_builder/solvers/orography_solver" icon="mountain">
    Analyzes topographic features around a site for wind loading calculations
  </Card>

  <Card title="Roughness Point Solver" href="/calcs_builder/solvers/roughness_point_solver" icon="map-pin">
    Determines terrain roughness characteristics for wind analysis
  </Card>

  <Card title="USGS API Solver" href="/calcs_builder/solvers/usgs_api_solver" icon="house-crack">
    Retrieves seismic design parameters from USGS web services
  </Card>
</CardGroup>

## Common Features

All GIS solvers share these characteristics:

* **Location-based**: Use latitude and longitude coordinates to fetch location-specific data
* **External APIs**: Connect to third-party services for authoritative data
* **Error handling**: Gracefully handle API failures with fallback values
* **Unit awareness**: Return properly formatted engineering units

## Integration with Templates

GIS solvers are typically implemented as remote widgets in templates:

<CodeBlock title="Basic GIS Solver Implementation">
  ```json theme={null}
  {
      "type": "sheetTemplateWidgets",
      "attributes": {
          "type": "remote",
          "solver": "gisOrography",
          "equation": [
              {
                  "condition": "@default",
                  "result": "{
                      latitude: projectDefault(\"latitude\", 40.7128) deg,
                      longitude: projectDefault(\"longitude\", -74.0060) deg,
                      z: building_height,
                      numSectors: 12
                  }"
              }
          ],
          "referenceId": "orography_data"
      }
  }
  ```
</CodeBlock>

<Note>
  GIS solvers require internet connectivity and may experience temporary outages from external services. Always implement appropriate fallback mechanisms in your templates.
</Note>