- The primary purpose of this module is to generate and manipulate transects (lines orthogonal to a given polygon) using geospatial data. It provides functionality to create these transects and expand them horizontally.
#### Critical Functions
1.**offsetMapper(extent, origin, theta)**
- Creates a function that maps offsets to transects based on the given extent, origin, and angle (theta).
2.**transectAccumulator(step, extent)**
- Accumulates transects by iterating over a list of coordinates, computing the necessary transects at each step.
- Generates transects orthogonal to a specified polygon based on the provided coordinates, step size, and extent.
4.**expandHorizontally(transects, amount)**
- Expands the generated transects horizontally by a specified amount.
#### Key Variables
-**extent**: The width of the transect.
-**origin**: The starting point for computing displacements.
-**theta**: The angle used for computing the direction of the transect.
-**step**: The distance between consecutive transects.
-**coordinates**: The list of coordinates defining the polygon.
-**amount**: The amount by which to expand the transects horizontally.
#### Interdependencies
-**Earth Engine (ee)**: The module heavily relies on Google Earth Engine (GEE) for geospatial computations and data structures.
-**Geodesy Module**: Functions like `computeBearing` and `computeDisplacement` are imported from the geodesy module to perform geospatial calculations.
-**Metadata Module**: Uses `INTERNALS` from the metadata module to store additional information in the generated features.
#### Core vs. Auxiliary Operations
-**Core Operations**:
-`generateOrthogonalTransects`: Main function to generate transects.
-`transectAccumulator`: Core logic for accumulating transects.
-**Auxiliary Operations**:
-`offsetMapper`: Helper function for mapping offsets to transects.
-`expandHorizontally`: Function to expand transects horizontally.
#### Operational Sequence
1.**Initialization**: Import necessary modules and define helper functions.
2.**Transect Generation**:
- Use `generateOrthogonalTransects` to create transects based on input coordinates.
- Internally, `transectAccumulator` and `offsetMapper` are used to compute and accumulate transects.
3.**Expansion**:
- Optionally, use `expandHorizontally` to expand the generated transects.
#### Performance Aspects
-**Efficiency**: The use of Earth Engine's efficient data structures and algorithms ensures that the module can handle large geospatial datasets.
-**Scalability**: Designed to work with GEE, which is optimized for large-scale geospatial analysis.
#### Reusability
-**Modular Design**: Functions are designed to be reusable and can be easily integrated into other geospatial analysis workflows.
-**Parameterization**: Functions accept parameters like `coordinates`, `step`, and `extent`, making them adaptable to different use cases.
#### Usage
-**Geospatial Analysis**: Used in applications requiring the generation of transects for environmental monitoring, land use analysis, and other geospatial studies.
-**Integration**: Can be integrated into larger geospatial analysis pipelines within the GEE environment.
#### Assumptions
-**Coordinate System**: Assumes that the input coordinates are in a format compatible with GEE.
-**Earth Engine Availability**: Assumes that the Google Earth Engine service is available and accessible.
-**Geodesy Functions**: Assumes that `computeBearing` and `computeDisplacement` functions are correctly implemented and available.
This analysis provides a detailed overview of the `transects.js` module, highlighting its purpose, key components, and usage within geospatial analysis workflows.
B -->|Coordinates, Step, Extent| C[transectAccumulator]
C -->|Extent, Origin, Theta| D[offsetMapper]
B -->|Transects| E[expandHorizontally]
E -->|Amount| F[computeBearing]
E -->|Amount| G[computeDisplacement]
B -->|Transects| H[Output Transects]
E -->|Expanded Transects| H
```
## Module: transects.js
### Comprehensive Analysis of `transects.js`
#### Module Name
-**transects.js**
#### Primary Objectives
- The primary purpose of this module is to generate and manipulate transects (lines orthogonal to a given polygon) using geospatial data. It provides functionality to create these transects and expand them horizontally.
#### Critical Functions
1.**offsetMapper(extent, origin, theta)**
-**Role**: Creates a function that maps offsets to transects based on the given extent, origin, and angle (theta).
2.**transectAccumulator(step, extent)**
-**Role**: Accumulates transects along a path defined by a series of coordinates, using a specified step size and extent.
-**Role**: Generates transects orthogonal to a specified polygon based on given coordinates, step size, and extent.
4.**expandHorizontally(transects, amount)**
-**Role**: Expands the generated transects horizontally by a specified amount.
#### Key Variables
-**extent**: Represents the extent of the transect.
-**origin**: The starting point for displacement calculations.
-**theta**: The angle used for calculating bearings and displacements.
-**step**: The step size for generating transects.
-**coordinates**: List of coordinates defining the polygon.
-**amount**: The amount by which to expand the transects horizontally.
#### Interdependencies
-**Earth Engine (ee)**: The module heavily relies on Google Earth Engine (GEE) for geospatial computations and data structures.
-**Geodesy Module**: Functions like `computeBearing` and `computeDisplacement` are imported from the geodesy module for geospatial calculations.
-**Metadata Module**: Uses `INTERNALS` from the metadata module to store additional information in features.
#### Core vs. Auxiliary Operations
-**Core Operations**:
-`generateOrthogonalTransects`: Main function for generating transects.
-`transectAccumulator`: Core logic for accumulating transects.
-**Auxiliary Operations**:
-`offsetMapper`: Helper function for mapping offsets to transects.
-`expandHorizontally`: Utility function for expanding transects.
#### Operational Sequence
1.**Initialization**: Import necessary modules and define helper functions.
2.**Transect Generation**:
- Use `generateOrthogonalTransects` to create transects based on input coordinates.
- Internally, `transectAccumulator` and `offsetMapper` are used to compute and accumulate transects.
3.**Expansion**:
- Optionally, use `expandHorizontally` to expand the generated transects.
#### Performance Aspects
-**Efficiency**: The use of Earth Engine's efficient data structures and algorithms ensures that the module can handle large geospatial datasets.
-**Scalability**: Designed to work with large-scale geospatial data, leveraging GEE's cloud-based processing capabilities.
#### Reusability
-**Modular Design**: Functions are designed to be reusable and can be easily integrated into other geospatial analysis workflows.
-**Parameterization**: Functions accept parameters like `coordinates`, `step`, and `extent`, making them adaptable to different use cases.
#### Usage
-**Geospatial Analysis**: Used in applications requiring the generation of transects for environmental monitoring, land use analysis, and other geospatial studies.
-**Integration**: Can be integrated into larger geospatial data processing pipelines using Google Earth Engine.
#### Assumptions
-**Coordinate System**: Assumes input coordinates are in a format compatible with Earth Engine.
-**Earth Engine Availability**: Assumes that the Google Earth Engine service is available and accessible.
-**Geodesy Functions**: Assumes that `computeBearing` and `computeDisplacement` functions are correctly implemented and available.
This analysis provides a detailed overview of the `transects.js` module, highlighting its purpose, key components, and usage within geospatial data processing workflows.
