Convert API code snippets from JS to Py

PiperOrigin-RevId: 571372709

samples/python/apidocs/ee_image_pixelarea.py

@@ -0,0 +1,75 @@
+# Copyright 2023 The Google Earth Engine Community Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# [START earthengine__apidocs__ee_image_pixelarea]
+# Create a pixel area image. Pixel values are square meters based on
+# a given CRS and scale (or CRS transform).
+pixel_area = ee.Image.pixelArea()
+
+# The default projection is WGS84 with 1-degree scale.
+display('Pixel area default projection', pixel_area.projection())
+
+# When inspecting the output in the Code Editor map, the scale of analysis is
+# determined by the zoom level. As you zoom in and out, you'll notice that the
+# area of the clicked pixel changes. To set a specific pixel scale when
+# performing a computation, provide an argument to the `scale` or
+# `crsTransform` parameters whenever a function gives you the option.
+m = geemap.Map()
+m.add_ee_layer(pixel_area, None, 'Pixel area for inspection', False)
+
+# The "area" band produced by the `pixel_area` function can be useful for
+# calculating the area of a certain condition of another image. For example,
+# here we use the sum reducer to determine the area above 2250m in the North
+# Cascades ecoregion, according to a 30m digital elevation model.
+
+# Import a DEM and subset the "elevation" band.
+elev = ee.Image('NASA/NASADEM_HGT/001').select('elevation')
+
+# Define a high elevation mask where pixels with elevation greater than 2250m
+# are set to 1, otherwise 0.
+high_elev_mask = elev.gt(2250)
+
+# Apply the high elevation mask to the pixel area image.
+high_elev_area = pixel_area.updateMask(high_elev_mask)
+
+# Import an ecoregion feature collection and filter it by ecoregion name.
+ecoregion = ee.FeatureCollection('RESOLVE/ECOREGIONS/2017').filter(
+    'ECO_NAME == "North Cascades conifer forests"'
+)
+
+# Display the ecoregion and high elevation area.
+m.set_center(-121.127, 48.389, 7)
+m.add_ee_layer(ecoregion, None, 'North Cascades ecoregion')
+m.add_ee_layer(
+    high_elev_area.clip(ecoregion), {'palette': 'yellow'}, 'High elevation area'
+)
+display(m)
+
+# Sum the area of high elevation pixels in the North Cascades ecoregion.
+area = high_elev_area.reduceRegion(
+    reducer=ee.Reducer.sum(),
+    geometry=ecoregion,
+    crs=elev.projection(),  # DEM coordinate reference system
+    crsTransform=elev.projection().getInfo()['transform'],  # DEM grid alignment
+    maxPixels=1e8,
+)
+
+# Fetch the summed area property from the resulting dictionary and convert
+# square meters to square kilometers.
+square_meters = area.getNumber('area')
+square_kilometers = square_meters.divide(1e6)
+
+display('Square meters above 2250m elevation', square_meters)
+display('Square kilometers above 2250m elevation', square_kilometers)
+# [END earthengine__apidocs__ee_image_pixelarea]

samples/python/apidocs/ee_image_sample.py

@@ -0,0 +1,82 @@
+# Copyright 2023 The Google Earth Engine Community Authors
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#    https://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+# [START earthengine__apidocs__ee_image_sample]
+# Demonstrate extracting pixels from an image as features with
+# ee.Image.sample(), and show how the features are aligned with the pixels.
+
+# An image with one band of elevation data.
+image = ee.Image('CGIAR/SRTM90_V4')
+vis_min = 1620
+vis_max = 1650
+m = geemap.Map()
+m.add_ee_layer(image, {'min': vis_min, 'max': vis_max}, 'SRTM')
+
+# Region to sample.
+region = ee.Geometry.Polygon(
+    [[
+        [-110.006, 40.002],
+        [-110.006, 39.999],
+        [-109.995, 39.999],
+        [-109.995, 40.002],
+    ]],
+    None,
+    False,
+)
+# Show region on the map.
+m.set_center(-110, 40, 16)
+
+m.add_ee_layer(ee.FeatureCollection([region]).style(color='00FF0022'))
+
+# Perform sampling convert image pixels to features.
+samples = image.sample(
+    region=region,
+    # Default (False) is no geometries in the output.
+    # When set to True, each feature has a Point geometry at the center of the
+    # image pixel.
+    geometries=True,
+    # The scale is not specified, so the resolution of the image will be used,
+    # and there is a feature for every pixel. If we give a scale parameter, the
+    # image will be resampled and there will be more or fewer features.
+    #
+    # scale=200,
+)
+
+
+def scale_point_size(feature):
+  elevation = feature.getNumber('elevation')
+  point_size = elevation.unitScale(vis_min, vis_max).multiply(15)
+  feature.set('style', {'pointSize': point_size})
+  return feature
+
+
+# Visualize sample data using ee.FeatureCollection.style().
+styled = samples.map(scale_point_size).style(
+    color='000000FF',
+    fillColor='00000000',
+    styleProperty='style',
+    neighborhood=6,  # increase to correctly draw large points
+)
+m.add_ee_layer(styled)
+display(m)
+
+# Each sample feature has a point geometry and a property named 'elevation'
+# corresponding to the band named 'elevation' of the image. If there are
+# multiple bands they will become multiple properties. This will print:
+#
+# geometry: Point (-110.01, 40.00)
+# properties:
+#   elevation: 1639
+display(samples.first())
+# [END earthengine__apidocs__ee_image_sample]