因为这次要用到点的数据，所以首先看要用到的工具：
一座山从底下到山顶的一个爬坡变化情况
ui.Chart.image.byRegion(image, regions, reducer, scale, xProperty)
Generates a Chart from an image. Extracts and plots band values in one or more regions in the image, with each band in a separate series.
- X-axis = Region labeled by xProperty (default: 'system:index')
- Y-axis = Reducer output.
- Series = Band name.//这里明确给出了用byRegion就是返回一个序列
Returns a chart.
Arguments:
image (Image):
Image to extract band values from.
regions (Feature|FeatureCollection|Geometry|List<Feature>|List<Geometry>, optional):
Regions to reduce. Defaults to the image's footprint.
reducer (Reducer, optional):
Reducer that generates the value(s) for the y-axis. Must return a single value per band. Defaults to ee.Reducer.mean().
scale (Number, optional):
Scale to use with the reducer in meters.
xProperty (String, optional):
Property to be used as the label for each Region on the x-axis. Defaults to 'system:index'.
Returns: ui.Chart
var elevation = ee.Image('CGIAR/SRTM90_V4'); //这个就是你要测量的点的位置信息并且可以命名名字 var waypoints = [ ee.Feature( ee.Geometry.Point([-121.7353, 46.78622]), {'name': 'Paradise Ranger Station'}), ee.Feature( ee.Geometry.Point([-121.72529, 46.8093]), {'name': 'Pebble Creek'}), ee.Feature( ee.Geometry.Point([-121.72585, 46.8102899]), {'name': 'Start of Glacier'}), ee.Feature( ee.Geometry.Point([-121.7252699, 46.81202]), {'name': 'Glacier Point 1'}), ee.Feature( ee.Geometry.Point([-121.72453, 46.81661]), {'name': 'Glacier Point 2'}), ee.Feature( ee.Geometry.Point([-121.72508, 46.82262]), {'name': 'Little Africa'}), ee.Feature( ee.Geometry.Point([-121.7278699, 46.82648]), {'name': 'Moon Rocks'}), ee.Feature(ee.Geometry.Point([-121.73281, 46.8354]), {'name': 'Camp Muir'}), ee.Feature(ee.Geometry.Point([-121.75976, 46.85257]), {'name': 'Summit'}) ]; //把这些点的集合弄成一个矢量集合，就是点要素 var rainierWaypoints = ee.FeatureCollection(waypoints); //绘图用通过地图元素的形式进行绘制 var chart = ui.Chart.image.byRegion({ image: elevation, regions: rainierWaypoints, //设置你要统计分辨率，越小越精确 scale: 200, xProperty: 'name' }); chart.setOptions({ title: 'Mt. Rainier Summit Trail Elevation', width:1000, height:500, vAxis: { title: 'Elevation (meters)' }, //图例的设置 legend: 'none', lineWidth: 1, pointSize: 4 }); print(chart); Map.addLayer(elevation, {min: 500, max: 4500}); Map.addLayer(rainierWaypoints, {color: 'FF0000'}); Map.setCenter(-121.75976, 46.85257, 11);
这是修改参数后的图形，设置了图形的长宽看起来更加合理
