Changes

Page history
Update Google Earth Engine Code Documentation authored by Ramicés dos Santos Silva's avatar Ramicés dos Santos Silva
Show whitespace changes
Inline Side-by-side
Google-Earth-Engine-Code-Documentation.md
View page @ 710ece28
Aqui
\ No newline at end of file
<details>
<summary>
# Summary
</summary>
[[_TOC_]]
</details>
The code performs the following steps:
1. Defines an array of baseline coordinates and another set of
coordinates for a different region.
2. Creates a baseline geometry using the baseline coordinates and adds
it as a layer to the map.
3. Generates orthogonal transects based on the baseline coordinates and
adds them as a layer to the map.
4. Filters an image collection based on a geometry and a date range.
5. Retrieves the number of images in the image collection and converts
it to a list.
6. Iterates over each image in the list and performs several
operations:
1. Adds the image as a layer to the map.
2. Retrieves the green and near-infrared bands of the image.
3. Identifies water features in the image using a threshold value.
4. If water features are found, it performs the following steps:
1. Calculates the shoreline by intersecting the water features
with a buffered geometry.
2. Removes noise from the shoreline.
3. Applies a Gaussian filter to smoothen the shoreline.
4. Creates a feature for the shoreline and adds it as a layer
to the map.
5. Appends the shoreline feature to an evaluated array.
7. Calculates the statistics of the evaluated shorelines along the
transects.
8. Generates visualizations of the transects and shoreline statistics.
9. Calculates the intersections between the first transect and each
shoreline feature.
10. Prints the results of the intersections.
11. Centers the map on the baseline geometry.
Overall, the code processes a collection of satellite images to identify
and analyze shorelines using transects and calculates statistics related
to the shorelines.
<hr>
#### **applyScaleFactors**
`Applies scale factors to the input image.`
``` javascript
function applyScaleFactors(image) {
var opticalBands = image.select('SR_B.').multiply(0.0000275).add(-0.2);
var thermalBands = image.select('ST_B.*').multiply(0.00341802).add(149.0);
return image.addBands(opticalBands, null, true).addBands(thermalBands, null, true);
}
```
##### **Inputs:**
\- image: The input image to apply scale factors. Must be an Earth
Engine image.
##### **Output:**
\- The output image with scale factors applied.
##### **Use**
\- Call the function as follows:
``` javascript
applyScaleFactors(image);
```
<hr>
#### **centerMapOnGeometry**
Centers the map on a specified geometry.
``` javascript
function centerMapOnGeometry(){
//center in the first point defined in geometry
var list = geometry.coordinates();
var point = list.getInfo();
Map.setCenter(point[0][0][0],point[0][0][1],13);
}
```
##### **Inputs:**
\- No input parameters for this function.
##### **Output:**
\- No output for this function.
##### **Use**
\- Call the function as follows:
``` javascript
centerMapOnGeometry();
```
<hr>
#### **gaussianKernel**
Calculates a Gaussian kernel with a specified size, mean, and sigma.
``` javascript
var gaussianKernel = function (size, mean, sigma) {
var gaussianCurve = function (x, mean, sigma) {
var divider = ee
.Number(sigma)
.multiply(ee.Number(2).multiply(Math.PI).sqrt());
var exponent = ee.Number(-1).multiply(
ee
.Number(x)
.subtract(mean)
.pow(2)
.divide(ee.Number(2).multiply(ee.Number(sigma).pow(2)))
);
return ee.Number(1).divide(divider).multiply(exponent.exp());
};
var half = ee.Number(size).divide(2).floor();
var begin = ee.Number(0).subtract(half),
end = ee.Number(0).add(half);
// Get the normal distribution Y value for each X
// in the interval
var kernel = ee.List.sequence(begin, end).map(function (i) { return gaussianCurve(i, mean, sigma)});
var sum = kernel.reduce(ee.Reducer.sum());
// Normalize each value, so that the sum of the list
// will be equal to one
var normalizedKernel = kernel.map(function (val) { return ee.Number(val).divide(sum)});
return normalizedKernel;
};
```
##### **Inputs:**
\- size: The size of the kernel. Must be a positive integer. - mean: The
mean of the Gaussian distribution. - sigma: The standard deviation of
the Gaussian distribution.
##### **Output:**
\- normalizedKernel: A list of values representing the normalized
Gaussian kernel.
##### **Use**
\- Call the function as follows:
``` javascript
var kernel = gaussianKernel(5, 0, 1);
```
<hr>
#### **linearGaussianFilter**
Calculates a linear Gaussian filter using a given set of coordinates.
``` javascript
var linearGaussianFilter = function (
coordinates
) {
var samples = 3;
var mean = 0;
var sd = 1;
var coordinateList = ee.List(coordinates);
// Setup gauss distribution kernel parameters
var kernelSize = ee.Number(samples);
var kernelMean = ee.Number(mean);
var kernelSd = ee.Number(sd);
var kernel = gaussianKernel(kernelSize, kernelMean, kernelSd);
var first = coordinateList.reduce(ee.Reducer.first()),
last = coordinateList.reduce(ee.Reducer.last());
var sequence = ee.List.sequence(
ee.Number(0),
coordinateList.length().subtract(kernelSize)
);
var path = sequence.map(function (index) {
// Take interval of the kernel size to apply the smoothing
// and zip it to the kernel, so each element in the new list
// will be a pair of a 2d point and its weight
var interval = coordinateList
.slice(ee.Number(index), ee.Number(index).add(kernelSize))
.zip(kernel);
// Map the elements, multiplying their axis values by their weight
var gaussian = interval.map(function (element) {
// Each element contains a 2d point (0) and a kernel weight (1)
var asList = ee.List(element);
var point = ee.List(asList.get(0));
var weight = ee.Number(asList.get(1));
// Now we map the two values (each point dimention), multiplying to the weight
return point.map( function (value) { return ee.Number(value).multiply(weight)});
});
// Sum longitude and latitude separately
var smoothenLong = gaussian
.map(function (point){ return ee.List(point).get(0)})
.reduce(ee.Reducer.sum());
var smoothenLat = gaussian
.map(function (point) { return ee.List(point).get(1)})
.reduce(ee.Reducer.sum());
// Return final smoothen point
return ee.List([smoothenLong, smoothenLat]);
});
var smoothen = ee.List([]).add(first).cat(path).add(last);
// return original coordinates if the kernelSize is less than or equal to the length
// of the given coordinates, otherwise return smoothen coordinates.
return ee.Algorithms.If(
coordinateList.size().lte(kernelSize),
coordinateList,
smoothen
);
};
```
##### **Inputs:**
\- coordinates: A list of coordinates to be filtered.
##### **Output:**
\- If the length of the given coordinates is less than or equal to the
kernel size, the function returns the original coordinates. Otherwise,
it returns the smoothened coordinates.
##### **Use**
\- Call the function as follows:
``` javascript
var filteredCoordinates = linearGaussianFilter(coordinates);
```
<hr>
#### **removeShorelineNoise**
`This function removes noise from shorelines by calculating the intersection between the shorelines and transects, and returning the geometry with the highest weight.`
``` javascript
var removeShorelineNoise = function (shorelines, transects) {
var coordinates = ee.Geometry(shorelines).coordinates();
var guard = ee.List(
ee.Algorithms.If(
ee.Geometry(shorelines).type().compareTo("MultiLineString").eq(0),
coordinates,
[coordinates]
)
);
```
##### **Inputs:**
\- shorelines: a geometry representing the shorelines to remove noise
from. - transects: a geometry representing the transects to calculate
the intersection with the shorelines.
``` javascript
var shorelines = ee.Geometry.LineString([[0, 0], [1, 1], [1, 2]]);
var transects = ee.Geometry.LineString([[0, 1], [1, 1]]);
var noiselessShoreline = removeShorelineNoise(shorelines, transects);
```
##### **Output:**
\- a geometry representing the noiseless shoreline.
``` javascript
var noiselessShoreline = removeShorelineNoise(shorelines, transects);
print(noiselessShoreline);
```
##### **Use**
To use this function, follow these steps: - Define the shorelines and
transects geometries. - Call the removeShorelineNoise function with the
shorelines and transects geometries as inputs. - The function will
return a geometry representing the noiseless shoreline.
``` javascript
var shorelines = ee.Geometry.LineString([[0, 0], [1, 1], [1, 2]]);
var transects = ee.Geometry.LineString([[0, 1], [1, 1]]);
var noiselessShoreline = removeShorelineNoise(shorelines, transects);
Map.addLayer(shorelines, {}, "Shorelines");
Map.addLayer(transects, {}, "Transects");
Map.addLayer(noiselessShoreline, {}, "Noiseless shoreline");
```
<hr>
#### **toDegrees**
This function converts longitude and latitude values from radians to
degrees.
``` javascript
var toDegrees = function (lng, lat) {
lat = lat.multiply(180 / Math.PI);
lng = lng.multiply(180 / Math.PI);
return [lng.add(540).mod(360).subtract(180), lat];
};
```
##### **Inputs:**
\- lng: a number representing the longitude value in radians. - lat: a
number representing the latitude value in radians.
``` javascript
var lng = ee.Number(0.7853981634); // 45 degrees in radians
var lat = ee.Number(0.5235987756); // 30 degrees in radians
var degrees = toDegrees(lng, lat);
```
##### **Output:**
\- an array containing the converted longitude and latitude values in
degrees.
``` javascript
var degrees = toDegrees(lng, lat);
print(degrees);
```
##### **Use**
To use this function, follow these steps: - Define the longitude and
latitude values in radians. - Call the toDegrees function with the
longitude and latitude values as inputs. - The function will return an
array containing the converted longitude and latitude values in degrees.
``` javascript
var lng = ee.Number(0.7853981634); // 45 degrees in radians
var lat = ee.Number(0.5235987756); // 30 degrees in radians
var degrees = toDegrees(lng, lat);
print(degrees);
```
<hr>
#### **computeDisplacement**
This function computes the new longitude and latitude coordinates based
on the input longitude, latitude, angle (theta), and distance.
``` javascript
var computeDisplacement = function (lng, lat, theta, distance) {
...
};
```
##### **Inputs:**
\- lng: a number representing the longitude value in degrees. - lat: a
number representing the latitude value in degrees. - theta: a number
representing the angle in degrees. - distance: a number representing the
distance in meters.
``` javascript
var lng = ee.Number(-122.4194); // San Francisco longitude
var lat = ee.Number(37.7749); // San Francisco latitude
var theta = ee.Number(45); // 45 degrees angle
var distance = ee.Number(1000); // 1000 meters distance
var newCoordinates = computeDisplacement(lng, lat, theta, distance);
```
##### **Output:**
\- an array containing the new longitude and latitude coordinates.
``` javascript
var newCoordinates = computeDisplacement(lng, lat, theta, distance);
print(newCoordinates);
```
##### **Use**
To use this function, follow these steps: - Define the longitude,
latitude, angle (theta), and distance values. - Call the
computeDisplacement function with the longitude, latitude, angle, and
distance values as inputs. - The function will return an array
containing the new longitude and latitude coordinates.
``` javascript
var lng = ee.Number(-122.4194); // San Francisco longitude
var lat = ee.Number(37.7749); // San Francisco latitude
var theta = ee.Number(45); // 45 degrees angle
var distance = ee.Number(1000); // 1000 meters distance
var newCoordinates = computeDisplacement(lng, lat, theta, distance);
print(newCoordinates);
```
<hr>
#### **offsetMapper**
This function creates a mapping function that takes an offset value and
returns a feature representing a line segment.
``` javascript
var offsetMapper = function (extent, origin, theta) {
...
};
```
##### **Inputs:**
\- extent: a number representing the extent value. - origin: an array
containing the origin coordinates. - theta: a number representing the
angle in degrees.
``` javascript
var extent = ee.Number(1000); // extent value
var origin = [ee.Number(-122.4194), ee.Number(37.7749)]; // origin coordinates
var theta = ee.Number(45); // 45 degrees angle
var mappingFunction = offsetMapper(extent, origin, theta);
```
##### **Output:**
\- a feature representing a line segment.
``` javascript
var mappingFunction = offsetMapper(extent, origin, theta);
print(mappingFunction);
```
##### **Use**
To use this function, follow these steps: - Define the extent, origin
coordinates, and angle (theta) values. - Call the offsetMapper function
with the extent, origin, and theta values as inputs. - The function will
return a mapping function that takes an offset value and returns a
feature representing a line segment.
``` javascript
var extent = ee.Number(1000); // extent value
var origin = [ee.Number(-122.4194), ee.Number(37.7749)]; // origin coordinates
var theta = ee.Number(45); // 45 degrees angle
var mappingFunction = offsetMapper(extent, origin, theta);
print(mappingFunction);
```
<hr>
#### **toRadians**
This function converts a value from degrees to radians.
``` javascript
var toRadians = function (value) {
...
};
```
##### **Inputs:**
\- value: a number representing the value in degrees.
``` javascript
var value = 45; // 45 degrees
var radians = toRadians(value);
```
##### **Output:**
\- a number representing the value in radians.
``` javascript
var value = 45; // 45 degrees
var radians = toRadians(value);
print(radians);
```
##### **Use**
To use this function, follow these steps: - Define the value in degrees
that you want to convert to radians. - Call the toRadians function with
the value as an input. - The function will return the value converted to
radians.
``` javascript
var value = 45; // 45 degrees
var radians = toRadians(value);
print(radians);
```
<hr>
#### **computeBearing**
This function calculates the bearing between two points on the Earth's
surface using their longitude and latitude coordinates.
``` javascript
var computeBearing = function (lng1, lat1, lng2, lat2) {
...
};
```
##### **Inputs:**
\- lng1: a number representing the longitude of the first point. - lat1:
a number representing the latitude of the first point. - lng2: a number
representing the longitude of the second point. - lat2: a number
representing the latitude of the second point.
``` javascript
var lng1 = -122.4194; // longitude of the first point
var lat1 = 37.7749; // latitude of the first point
var lng2 = -122.4313; // longitude of the second point
var lat2 = 37.7675; // latitude of the second point
var bearing = computeBearing(lng1, lat1, lng2, lat2);
```
##### **Output:**
\- a number representing the bearing between the two points.
``` javascript
var lng1 = -122.4194; // longitude of the first point
var lat1 = 37.7749; // latitude of the first point
var lng2 = -122.4313; // longitude of the second point
var lat2 = 37.7675; // latitude of the second point
var bearing = computeBearing(lng1, lat1, lng2, lat2);
print(bearing);
```
##### **Use**
To use this function, follow these steps: - Define the longitude and
latitude coordinates of the two points. - Call the computeBearing
function with the longitude and latitude values as inputs. - The
function will return the bearing between the two points.
``` javascript
var lng1 = -122.4194; // longitude of the first point
var lat1 = 37.7749; // latitude of the first point
var lng2 = -122.4313; // longitude of the second point
var lat2 = 37.7675; // latitude of the second point
var bearing = computeBearing(lng1, lat1, lng2, lat2);
print(bearing);
```
<hr>
#### **transectAccumulator**
This function is a higher-order function that returns another function.
The returned function is used to accumulate and process data for
generating transects along a line segment.
``` javascript
var transectAccumulator = function (step, extent) {
...
};
```
##### **Inputs:**
\- step: a number representing the distance between each transect. -
extent: a number representing the total distance of the line segment.
``` javascript
var step = 10; // distance between each transect
var extent = 100; // total distance of the line segment
var accumulator = transectAccumulator(step, extent);
```
##### **Output:**
\- a function that accumulates and processes data for generating
transects along a line segment.
``` javascript
var step = 10; // distance between each transect
var extent = 100; // total distance of the line segment
var accumulator = transectAccumulator(step, extent);
var result = accumulator(data);
```
##### **Use**
To use this function, follow these steps: - Define the distance between
each transect and the total distance of the line segment. - Call the
transectAccumulator function with the step and extent values as
inputs. - The function will return another function that can be used to
accumulate and process data for generating transects along a line
segment.
``` javascript
var step = 10; // distance between each transect
var extent = 100; // total distance of the line segment
var accumulator = transectAccumulator(step, extent);
var result = accumulator(data);
```
<hr>
#### **generateOrthogonalTransects**
This function generates orthogonal transects along a line segment.
``` javascript
var generateOrthogonalTransects = function (coordinates, step, extent) {
...
};
```
##### **Inputs:**
\- coordinates: a list of coordinates representing the line segment. -
step: a number representing the distance between each transect. -
extent: a number representing the total distance of the line segment.
``` javascript
var coordinates = [[0,0], [0,10], [10,10], [10,0]]; // list of coordinates representing the line segment
var step = 10; // distance between each transect
var extent = 100; // total distance of the line segment
var transects = generateOrthogonalTransects(coordinates, step, extent);
```
##### **Output:**
\- a list of orthogonal transects along the line segment.
``` javascript
var coordinates = [[0,0], [0,10], [10,10], [10,0]]; // list of coordinates representing the line segment
var step = 10; // distance between each transect
var extent = 100; // total distance of the line segment
var transects = generateOrthogonalTransects(coordinates, step, extent);
print(transects);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a list of coordinates
representing the line segment. - Define the distance between each
transect and the total distance of the line segment. - Call the
generateOrthogonalTransects function with the coordinates, step, and
extent values as inputs. - The function will return a list of orthogonal
transects along the line segment.
``` javascript
var coordinates = [[0,0], [0,10], [10,10], [10,0]]; // list of coordinates representing the line segment
var step = 10; // distance between each transect
var extent = 100; // total distance of the line segment
var transects = generateOrthogonalTransects(coordinates, step, extent);
print(transects);
```
<hr>
#### **thresholdingAlgorithm**
*`This`` ``function`` ``calculates`` ``the`` ``threshold`` ``value`` ``for`` ``image`` ``segmentation`` ``using`` ``the`` ``thresholding`` ``algorithm.`*
``` javascript
var thresholdingAlgorithm = function (histogram, count) {
...
};
```
##### **Inputs:**
\- histogram: a dictionary representing the histogram of pixel values in
an image. - count: the total count of pixels in the image.
``` javascript
var histogram = { "bucketMeans": [0, 1, 2, 3], "histogram": [10, 20, 30, 40] }; // example histogram
var count = 1000; // example count
var threshold = thresholdingAlgorithm(histogram, count);
```
##### **Output:**
\- the threshold value for image segmentation.
``` javascript
var histogram = { "bucketMeans": [0, 1, 2, 3], "histogram": [10, 20, 30, 40] }; // example histogram
var count = 1000; // example count
var threshold = thresholdingAlgorithm(histogram, count);
print(threshold);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a histogram
dictionary representing the histogram of pixel values in an image. -
Define the total count of pixels in the image. - Call the
thresholdingAlgorithm function with the histogram and count values as
inputs. - The function will return the threshold value for image
segmentation.
``` javascript
var histogram = { "bucketMeans": [0, 1, 2, 3], "histogram": [10, 20, 30, 40] }; // example histogram
var count = 1000; // example count
var threshold = thresholdingAlgorithm(histogram, count);
print(threshold);
```
<hr>
<hr>
#### **selectThreshold**
*This function selects a threshold value based on the given parameter.*
``` javascript
var selectThreshold = function (threshold) {
...
};
```
##### **Inputs:**
\- threshold: a numeric value representing the threshold to be selected.
``` javascript
var threshold = 0.0; // example threshold
var thresholdFunction = selectThreshold(threshold);
```
##### **Output:**
\- a function that takes image, band, \_, and scale as inputs and
returns a threshold value.
``` javascript
var threshold = 0.0; // example threshold
var thresholdFunction = selectThreshold(threshold);
var image = ee.Image("example_image"); // example image
var band = "example_band"; // example band
var scale = 30; // example scale
var selectedThreshold = thresholdFunction(image, band, _, scale);
print(selectedThreshold);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a threshold value. -
Call the selectThreshold function with the threshold value as input. -
The function will return a threshold function. - Call the threshold
function with image, band, \_, and scale values as inputs. - The
threshold function will return a selected threshold value.
``` javascript
var threshold = 0.0; // example threshold
var thresholdFunction = selectThreshold(threshold);
var image = ee.Image("example_image"); // example image
var band = "example_band"; // example band
var scale = 30; // example scale
var selectedThreshold = thresholdFunction(image, band, _, scale);
print(selectedThreshold);
```
<hr>
<hr>
#### **identifyWaterFeature**
*This function identifies water features in an image based on a given
threshold and returns the geometry of the water feature.*
``` javascript
var identifyWaterFeature = function (
image,
geometry,
scale,
band,
thresholdFn
){
...
};
```
##### **Inputs:**
\- image: an image representing the area of interest. - geometry: a
geometry object representing the region of interest. - scale: a numeric
value representing the scale at which to perform the analysis. - band: a
string representing the band to use for the analysis. - thresholdFn: a
function that calculates the threshold value for identifying water
features.
``` javascript
var image = ee.Image("example_image"); // example image
var geometry = ee.Geometry.Point(0, 0); // example geometry
var scale = 30; // example scale
var band = "example_band"; // example band
var thresholdFn = function (ndwi, band, geometry, scale) {
// example threshold function
var threshold = ee.Number(0.01);
return threshold;
};
var waterGeometry = identifyWaterFeature(image, geometry, scale, band, thresholdFn);
print(waterGeometry);
```
<hr>
##### **Output:**
\- a geometry object representing the water feature.
``` javascript
var image = ee.Image("example_image"); // example image
var geometry = ee.Geometry.Point(0, 0); // example geometry
var scale = 30; // example scale
var band = "example_band"; // example band
var thresholdFn = function (ndwi, band, geometry, scale) {
// example threshold function
var threshold = ee.Number(0.01);
return threshold;
};
var waterGeometry = identifyWaterFeature(image, geometry, scale, band, thresholdFn);
print(waterGeometry);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define an image, geometry,
scale, band, and threshold function. - Call the identifyWaterFeature
function with the defined inputs. - The function will return the
geometry of the identified water feature. - Print or use the
waterGeometry variable to access the geometry.
``` javascript
var image = ee.Image("example_image"); // example image
var geometry = ee.Geometry.Point(0, 0); // example geometry
var scale = 30; // example scale
var band = "example_band"; // example band
var thresholdFn = function (ndwi, band, geometry, scale) {
// example threshold function
var threshold = ee.Number(0.01);
return threshold;
};
var waterGeometry = identifyWaterFeature(image, geometry, scale, band, thresholdFn);
print(waterGeometry);
```
<hr>
<hr>
#### **generateTransectsStatistics**
*This function generates statistics for transects based on a given
baseline and shorelines, and returns the modified transects with
additional properties.*
``` javascript
var generateTransectsStatistics = function (
transects,
baseline,
shorelines,
keepProps
) {
...
};
```
##### **Inputs:**
\- transects: a feature collection representing the transects. -
baseline: a feature representing the baseline for distance
calculations. - shorelines: a feature collection representing the
shorelines for distance calculations. - keepProps: an array of property
names to keep from the original transects.
``` javascript
var transects = ee.FeatureCollection("example_transects"); // example transects
var baseline = ee.Feature("example_baseline"); // example baseline
var shorelines = ee.FeatureCollection("example_shorelines"); // example shorelines
var keepProps = ["prop1", "prop2"]; // example property names
var transectsStats = generateTransectsStatistics(transects, baseline, shorelines, keepProps);
print(transectsStats);
```
<hr>
##### **Output:**
\- a feature collection representing the modified transects with
additional properties.
``` javascript
var transects = ee.FeatureCollection("example_transects"); // example transects
var baseline = ee.Feature("example_baseline"); // example baseline
var shorelines = ee.FeatureCollection("example_shorelines"); // example shorelines
var keepProps = ["prop1", "prop2"]; // example property names
var transectsStats = generateTransectsStatistics(transects, baseline, shorelines, keepProps);
print(transectsStats);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define the transects,
baseline, shorelines, and keepProps. - Call the
generateTransectsStatistics function with the defined inputs. - The
function will return the modified transects with additional
properties. - Print or use the transectsStats variable to access the
modified transects.
``` javascript
var transects = ee.FeatureCollection("example_transects"); // example transects
var baseline = ee.Feature("example_baseline"); // example baseline
var shorelines = ee.FeatureCollection("example_shorelines"); // example shorelines
var keepProps = ["prop1", "prop2"]; // example property names
var transectsStats = generateTransectsStatistics(transects, baseline, shorelines, keepProps);
print(transectsStats);
```
<hr>
<hr>
#### **calculateDistances**
*This function calculates the distances between a transect and a
baseline, as well as the distances between the transect and multiple
shorelines. It returns a dictionary with the calculated distances and
additional metadata.*
``` javascript
var calculateDistances = function (transect, baseline, shorelines) {
...
};
```
##### **Inputs:**
\- transect: a feature representing the transect. - baseline: a feature
representing the baseline. - shorelines: a feature collection
representing the shorelines.
``` javascript
var transect = ee.Feature("example_transect"); // example transect
var baseline = ee.Feature("example_baseline"); // example baseline
var shorelines = ee.FeatureCollection("example_shorelines"); // example shorelines
var distances = calculateDistances(transect, baseline, shorelines);
print(distances);
```
<hr>
##### **Output:**
\- a dictionary containing the calculated distances and additional
metadata.
``` javascript
var transect = ee.Feature("example_transect"); // example transect
var baseline = ee.Feature("example_baseline"); // example baseline
var shorelines = ee.FeatureCollection("example_shorelines"); // example shorelines
var distances = calculateDistances(transect, baseline, shorelines);
print(distances);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define the transect,
baseline, and shorelines. - Call the calculateDistances function with
the defined inputs. - The function will return a dictionary with the
calculated distances and additional metadata. - Print or use the
distances variable to access the calculated distances.
``` javascript
var transect = ee.Feature("example_transect"); // example transect
var baseline = ee.Feature("example_baseline"); // example baseline
var shorelines = ee.FeatureCollection("example_shorelines"); // example shorelines
var distances = calculateDistances(transect, baseline, shorelines);
print(distances);
```
<hr>
<hr>
#### **withPrefix**
*This function takes a string as input and adds the prefix "cassie:" to
it. It returns the modified string.*
``` javascript
var withPrefix = function (str) { return "cassie:" + str};
```
##### **Inputs:**
\- str: a string that needs to be modified.
``` javascript
var str = "example string"; // example input string
var modifiedStr = withPrefix(str);
print(modifiedStr);
```
<hr>
##### **Output:**
\- a string with the prefix "cassie:" added to it.
``` javascript
var str = "example string"; // example input string
var modifiedStr = withPrefix(str);
print(modifiedStr);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a string that needs
to be modified. - Call the withPrefix function with the defined string
as the input. - The function will return the modified string. - Print or
use the modifiedStr variable to access the modified string.
``` javascript
var str = "example string"; // example input string
var modifiedStr = withPrefix(str);
print(modifiedStr);
```
<hr>
<hr>
#### **calculateStatistics**
*`This`` ``JavaScript`` ``function`` ``calculates`` ``various`` ``statistics`` ``from`` ``a`` ``given`` ``measurement.`` ``The`` ``measurement`` ``is`` ``expected`` ``to`` ``be`` ``a`` ``dictionary`` ``with`` ``distance`` ``and`` ``date`` ``values.`` ``The`` ``function`` ``calculates`` ``the`` ``earliest,`` ``latest,`` ``closest,`` ``and`` ``farthest`` ``measurements,`` ``as`` ``well`` ``as`` ``SCE`` ``(Shoreline`` ``Change`` ``Envelope),`` ``NSM`` ``(Net`` ``Shoreline`` ``Movement),`` ``EPR`` ``(End`` ``Point`` ``Rate),`` ``LRR`` ``(Linear`` ``Regression`` ``Rate),`` ``correlation,`` ``and`` ``R-squared`` ``values.`` ``Additionally,`` ``it`` ``labels`` ``the`` ``data`` ``using`` ``the`` ``Esteves`` ``method`` ``and`` ``formats`` ``the`` ``first`` ``and`` ``last`` ``dates`` ``to`` ``ISO`` ``standard`` ``format`` ``in`` ``UTC.`*
``` javascript
var calculateStatistics = function (measurement) {
...
};
```
##### **Inputs:**
\- measurement: a dictionary containing distance and date values for
each measurement.
``` javascript
var measurement = {distance: 100, date: new Date()}; // example input
var stats = calculateStatistics(measurement);
console.log(stats);
```
<hr>
##### **Output:**
\- A dictionary containing the calculated statistics: SCE, NSM, EPR,
LRR, correlation, R-squared values, Esteves label, first and last dates,
and internal data such as count, trend, and regression.
``` javascript
var measurement = {distance: 100, date: new Date()}; // example input
var stats = calculateStatistics(measurement);
console.log(stats);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a measurement
dictionary with distance and date values. - Call the calculateStatistics
function with the defined measurement as the input. - The function will
return a dictionary with the calculated statistics. - Use console.log or
similar to view the returned statistics.
``` javascript
var measurement = {distance: 100, date: new Date()}; // example input
var stats = calculateStatistics(measurement);
console.log(stats);
```
<hr>
<hr>
#### **estevesLabelling**
`This function is used to classify land cover based on a given Land Ruggedness Index (LRR) value.`
``` javascript
var estevesLabelling = function (lrr) {
var classification = ee.Algorithms.If(
lrr.lt(-1.0),
ESTEVES_LABELS["Critically Eroded"].class,
ee.Algorithms.If(
lrr.lt(-0.5),
ESTEVES_LABELS["Eroded"].class,
ee.Algorithms.If(
lrr.lt(0.5),
ESTEVES_LABELS["Stable"].class,
ESTEVES_LABELS["Accreted"].class
)
)
);
return ee.String(classification);
};
```
##### **Inputs:**
\- lrr: The Land Ruggedness Index (LRR) value used for classification.
##### **Output:**
\- Classification: The land cover classification based on the given LRR
value.
##### **Use**
1\. Define the Land Ruggedness Index (LRR) value. 2. Call the function
"estevesLabelling" with the LRR value as the input. 3. The function will
classify the land cover based on the LRR value and return the
classification.
``` javascript
<Given a code example for the call function>;
```
<hr>
#### **complementaryProperties**
*This function takes a transect, a measurement, and a list of properties
to keep as input. It generates complementary properties based on the
input and returns a summary with the combined properties.*
``` javascript
var complementaryProperties = function (transect, measurement, keepProps) {
var props = ee.Dictionary(
ee.Algorithms.If(keepProps, transect.toDictionary(keepProps), {})
);
/* Distances properties */
var distanceInfo = measurement.values();
var dates = serializeList(
distanceInfo.map( function (item) {
// Format Data as ISO standart formating and and UTC
return ee.Date(ee.Dictionary(item).get("date")).format(null, 'UTC')
})
);
var distances = serializeList(
distanceInfo.map(function (item) { return ee.Dictionary(item).getNumber("distance")})
);
/* Coordinates properties */
var coordinates = transect.geometry().coordinates();
var start = ee.List(coordinates.get(0)),
end = ee.List(coordinates.get(1));
var longStart = start.getNumber(0),
longEnd = end.getNumber(0);
var latStart = start.getNumber(1),
latEnd = end.getNumber(1);
/* Summary */
var summary = ee.Dictionary({
longStart: longStart,
longEnd: longEnd,
latStart: latStart,
latEnd: latEnd,
dates: dates,
distances: distances,
});
return summary.combine(props);
};
```
##### **Inputs:**
\- transect: The transect object. - measurement: The measurement
object. - keepProps: A list of properties to keep.
##### **Output:**
\- summary: A summary object containing the combined properties.
##### **Use**
To use this function, follow these steps: - Define a transect object. -
Define a measurement object. - Define a list of properties to keep
(optional). - Call the complementaryProperties function with the defined
transect, measurement, and keepProps as inputs. - The function will
generate complementary properties based on the input and return a
summary object with the combined properties.
``` javascript
var transect = ...; // define transect object
var measurement = ...; // define measurement object
var keepProps = ...; // define list of properties to keep (optional)
var summary = complementaryProperties(transect, measurement, keepProps);
print(summary);
```
<hr>
<hr>
#### **serializeList**
*This function takes a subject as input and serializes it into a string
format. It converts a list into a string representation enclosed in
square brackets.*
``` javascript
var serializeList = function (subject) {
return ee.String('"[').cat(ee.List(subject).join(",")).cat(']"');
};
```
##### **Inputs:**
\- subject: The list to be serialized.
``` javascript
var myList = [1, 2, 3]; // example input list
var serializedString = serializeList(myList);
print(serializedString);
```
<hr>
##### **Output:**
\- serializedString: A string representation of the input list, enclosed
in square brackets.
``` javascript
var myList = [1, 2, 3]; // example input list
var serializedString = serializeList(myList);
print(serializedString);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a list that needs to
be serialized. - Call the serializeList function with the defined list
as the input. - The function will return a string representation of the
input list, enclosed in square brackets. - Print or use the
serializedString variable to access the serialized list.
``` javascript
var myList = [1, 2, 3]; // example input list
var serializedString = serializeList(myList);
print(serializedString);
```
<hr>
<hr>
#### **combineReducers**
*This function takes two reducers as input and combines them into a
single reducer. It returns the combined reducer.*
``` javascript
var combineReducers = function (reducer01, reducer02) {
return reducer01.combine(reducer02, "", true);
};
```
##### **Inputs:**
\- reducer01: The first reducer to be combined. - reducer02: The second
reducer to be combined.
``` javascript
var reducer1 = ...; // example input reducer 1
var reducer2 = ...; // example input reducer 2
var combinedReducer = combineReducers(reducer1, reducer2);
print(combinedReducer);
```
<hr>
##### **Output:**
\- combinedReducer: The combined reducer.
``` javascript
var reducer1 = ...; // example input reducer 1
var reducer2 = ...; // example input reducer 2
var combinedReducer = combineReducers(reducer1, reducer2);
print(combinedReducer);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define two reducers that
need to be combined. - Call the combineReducers function with the
defined reducers as inputs. - The function will return the combined
reducer. - Print or use the combinedReducer variable to access the
combined reducer.
``` javascript
var reducer1 = ...; // example input reducer 1
var reducer2 = ...; // example input reducer 2
var combinedReducer = combineReducers(reducer1, reducer2);
print(combinedReducer);
```
<hr>
<hr>
#### **expandHorizontally**
*This function takes a list of transects and an amount as input. It
expands each transect horizontally by the specified amount and returns
the expanded transects.*
``` javascript
var expandHorizontally = function (transects, amount) {
amount = ee.Number(amount).divide(2);
var mapper = function (transect) {
transect = ee.Feature(transect);
var coords = transect.geometry().coordinates();
var a = ee.List(coords.get(0));
var b = ee.List(coords.get(1));
var theta = computeBearing(a.get(0), a.get(1), b.get(0), b.get(1)).add(
Math.PI
);
var alpha = theta.add(Math.PI * 0.5);
var beta = theta.subtract(Math.PI * 0.5);
var a1 = computeDisplacement(a.get(0), a.get(1), alpha, amount);
var a2 = computeDisplacement(a.get(0), a.get(1), beta, amount);
var b1 = computeDisplacement(b.get(0), b.get(1), alpha, amount);
var b2 = computeDisplacement(b.get(0), b.get(1), beta, amount);
var rectangle = ee.Feature(ee.Geometry.Polygon([[a1, a2, b2, b1]]));
return rectangle.copyProperties(transect);
};
return transects.map(mapper);
};
```
##### **Inputs:**
\- transects: A list of transects to be expanded. - amount: The amount
by which the transects should be expanded horizontally.
``` javascript
var transects = ...; // example input transects
var amount = 100; // example input amount
var expandedTransects = expandHorizontally(transects, amount);
print(expandedTransects);
```
<hr>
##### **Output:**
\- expandedTransects: The expanded transects.
``` javascript
var transects = ...; // example input transects
var amount = 100; // example input amount
var expandedTransects = expandHorizontally(transects, amount);
print(expandedTransects);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a list of transects
that need to be expanded. - Specify the amount by which the transects
should be expanded horizontally. - Call the expandHorizontally function
with the defined transects and amount as inputs. - The function will
return the expanded transects. - Print or use the expandedTransects
variable to access the expanded transects.
``` javascript
var transects = ...; // example input transects
var amount = 100; // example input amount
var expandedTransects = expandHorizontally(transects, amount);
print(expandedTransects);
```
<hr>
<hr>
#### **summaryShorelineStatistics**
`This function calculates summary statistics for shoreline distances.`
``` javascript
var summaryShorelineStatistics = function (transects, shorelines) {
// Code explanation goes here
};
```
##### **Inputs:**
\- transects: A list of transects. - shorelines: A feature collection of
shorelines.
##### **Output:**
\- A feature collection with summary statistics for each shoreline.
##### **Use**
`To use the summaryShorelineStatistics function, follow these steps:`
`1. Call the function and provide the transects and shorelines as inputs.`
2\. Retrieve the output feature collection.
``` javascript
var result = summaryShorelineStatistics(transects, shorelines);
```
<hr>
#### **sequence**
*This function generates a sequence of numbers starting from 0 up to a
given number n-1.*
``` javascript
var sequence = function (n) {
var start = 0;
return Array.from(Array(n).keys()).map(function (val) {return val + start});
};
```
##### **Inputs:**
\- n: a number indicating the length of the sequence.
``` javascript
var n = 5; // example input number
var result = sequence(n);
console.log(result);
```
<hr>
##### **Output:**
\- An array of numbers representing the sequence from 0 to n-1.
``` javascript
var n = 5; // example input number
var result = sequence(n);
console.log(result);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define a number n indicating
the length of the desired sequence. - Call the sequence function with n
as the input. - The function will return an array of numbers
representing the sequence. - Print or use the result variable to access
the generated sequence.
``` javascript
var n = 5; // example input number
var result = sequence(n);
console.log(result);
```
<hr>
<hr>
#### **generateColors**
*This function generates a specified number of colors based on the
amount and lightness parameters. It uses the ColorConverter library to
convert the colors from HSL to hexadecimal format.*
``` javascript
var generateColors = function (amount, lightness) {
var slice = amount=== 1 ? 0 : 240.0 / (amount - 1);
return sequence(amount).map(function (i) {
return "#" + ColorConverter.hsl.hex(slice * i, 100, lightness);
});
}
```
##### **Inputs:**
\- amount: a number indicating the desired number of colors to
generate. - lightness: a number indicating the lightness value for the
generated colors.
``` javascript
var amount = 5; // example input number
var lightness = 50; // example input number
var colors = generateColors(amount, lightness);
console.log(colors);
```
<hr>
##### **Output:**
\- An array of colors represented in hexadecimal format.
``` javascript
var amount = 5; // example input number
var lightness = 50; // example input number
var colors = generateColors(amount, lightness);
console.log(colors);
```
<hr>
##### **Use**
To use this function, follow these steps: - Define the amount of colors
to generate and the desired lightness value. - Call the generateColors
function with the defined parameters. - The function will return an
array of colors represented in hexadecimal format. - Print or use the
colors variable to access the generated colors.
``` javascript
var amount = 5; // example input number
var lightness = 50; // example input number
var colors = generateColors(amount, lightness);
console.log(colors);
```
<hr>
<hr>