Exercise 01: Load National Elevation Dataset for the entire United States. Compute slope and aspect. Display elevation, slope and aspect.

Transcription

1 Exercise 01: Load National Elevation Dataset for the entire United States. Compute slope and aspect. Display elevation, slope and aspect. 1 Clear script/ Click down arrow to the right of Reset button and then Clear script create new script 2 Load NED var elevation = ee.image('usgs/ned'); 3 Add comment to script // /**/ Ctrl-/ 4 Save script Click Save button Enter path and file name: 00Workshop/Exercise01 5 Print elevation object and check printed object 6 Add elevation to map // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // add NED to map Map.addLayer(elevation); 7 Use inspect panel to inspect elevation values 8 Adding elevation to map, including visualization parameters Inspect Layer Manager 9 Calculate and present slope Use Inspector panel to inspect elevation values (click at different locations and see how elevation values change). Use layer manager to inspect visualization parameters for elevation. // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // add NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // add NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); var slope = ee.terrain.slope(elevation); Sergio Bernardes, PhD 1

2 print(slope); Map.addLayer(slope,{min:0,max:45},'Slope'); 10 Calculate and present aspect // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // add NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); var slope = ee.terrain.slope(elevation); print(slope); Map.addLayer(slope,{min:0,max:45},'Slope'); var aspect = ee.terrain.aspect(elevation); print(aspect); Map.addLayer(aspect,{min:0,max:360},'Aspect'); 11 Centering the map around coordinates -83 longitude and 36 latitude // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // adds NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); var slope = ee.terrain.slope(elevation); print(slope); Map.addLayer(slope,{min:0,max:45},'Slope'); var aspect = ee.terrain.aspect(elevation); print(aspect); Map.addLayer(aspect,{min:0,max:360},'Aspect'); // centers map using long/lat coordinates and scale Map.setCenter(-83,36,14); 12 Adding a palette to 'slope' Show explanation on hexadecimal colors // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // adds NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); var slope = ee.terrain.slope(elevation); print(slope); Map.addLayer(slope,{min:0,max:45, Sergio Bernardes, PhD 2

3 palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'slope'); var aspect = ee.terrain.aspect(elevation); print(aspect); Map.addLayer(aspect,{min:0,max:360},'Aspect'); // centers map using long/lat coordinates and scale Map.setCenter(-83,36,14); 13 Select areas with high slope and mask out everything else // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // adds NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); var slope = ee.terrain.slope(elevation); print(slope); Map.addLayer(slope,{min:0,max:45, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'slope'); var aspect = ee.terrain.aspect(elevation); print(aspect); Map.addLayer(aspect,{min:0,max:360},'Aspect'); // centers map using long/lat coordinates and scale Map.setCenter(-83,36,14); // masks out slope below 25 var maskedslope25 = slope.updatemask(slope.gte(25)); Map.addLayer(maskedSlope25,{min:0,max:45, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'slope >= 25'); 14 Select a slope range and mask out everything else // Loads National Elevation Dataset var elevation = ee.image('usgs/ned'); print(elevation); // adds NED to map Map.addLayer(elevation, {min:0, max:4000},'ned'); var slope = ee.terrain.slope(elevation); print(slope); Map.addLayer(slope,{min:0,max:45, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'slope'); var aspect = ee.terrain.aspect(elevation); Sergio Bernardes, PhD 3

4 15 Save script Click Save button University of Georgia print(aspect); Map.addLayer(aspect,{min:0,max:360},'Aspect'); // centers map using long/lat coordinates and scale Map.setCenter(-83,36,14); // masks out slope below 25 var maskedslope25 = slope.updatemask(slope.gte(25)); Map.addLayer(maskedSlope25,{min:0,max:45, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'slope >= 25'); // masks out slope below 25 and above 30 var maskedslope2530 = slope.updatemask(slope.gte(25).and(slope.lte(30))); Map.addLayer(maskedSlope2530,{min:0,max:45, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'slope 25-30'); Sergio Bernardes, PhD 4

5 Exercise 02: Load Daymet for the entire domain. Filter the dataset and compute maximum temperature for Display layer of maximum temperature. Compute maximum temperature for Georgia in Clear script/ create new script (make sure you saved your previous script first) Click down arrow to the right of Reset button and then Clear script 2 Search for Daymet Use Search field to search for Daymet. Under RASTERS click on Daymet V3. Inspect Daymet characteristics: daily data, time interval ( ), bands, Copy Daymet ImageCollection ID to clipboard 3 Import Daymet var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing print(daymetcollection); 4 Search for Daymet and import collection to Imports section Comment the code above. We will use a different way to import Daymet //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); Use search field to search for Daymet. Under RASTERS click on Daymet V3. Click Import button to import Daymet into Imports section Slow double click the collection name to rename the collection to daymetcollection 5 We need to filter the dataset Filter by date (final date is outside interval) Check Console for "bands" 6 We need to filter the dataset by date and variable //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); // filters Daymet based on date (all images for 2015) var filtereddaymetcollection = daymetcollection.filterdate(' ',' '); print(filtereddaymetcollection); //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); Sergio Bernardes, PhD 5

6 Check the console for "bands" // filters Daymet based on date (all images for 2015) and variable var filtereddaymetcollection = daymetcollection.filterdate(' ',' ').select(['tmax']); print(filtereddaymetcollection); 7 Using reducers: Temporal NO FOR LOOPS Use Console to compare original (365 bands) with reduced (1 band) //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); // filters Daymet based on date (all images for 2015) and variable var filtereddaymetcollection = daymetcollection.filterdate(' ',' ').select(['tmax']); print(filtereddaymetcollection); // calculates maximum temperature for each pixel for 2015 var maxtemperature = filtereddaymetcollection.reduce(ee.reducer.max()); print(maxtemperature); 8 Display maxtemperature and center the map //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); // filters Daymet based on date (all images for 2015) and variable var filtereddaymetcollection = daymetcollection.filterdate(' ',' ').select(['tmax']); print(filtereddaymetcollection); // calculates maximum temperature for each pixel for the 2015 var maxtemperature = filtereddaymetcollection.reduce(ee.reducer.max()); print(maxtemperature); Map.addLayer(maxTemperature,{min:25,max:40, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'max temp'); Map.setCenter(-83,36,8); 9 Using reducers: Temporal Looking for rare //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); Sergio Bernardes, PhD 6

7 events: Percentile NO FOR LOOPS Present list of Reducers // filters Daymet based on date (all images for 2015) and variable var filtereddaymetcollection = daymetcollection.filterdate(' ',' ').select(['tmax']); print(filtereddaymetcollection); // calculates maximum temperature for each pixel for 2015 var maxtemperature = filtereddaymetcollection.reduce(ee.reducer.max()); print(maxtemperature); Map.addLayer(maxTemperature,{min:25,max:40, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'max temp'); Map.setCenter(-83,36,8); // looking for rare events: calculates 99 percentile for each pixel for 2015 var percent99 = filtereddaymetcollection.reduce(ee.reducer.percentile([99])); print(percent99); Map.addLayer(percent99, {min:25,max:40, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'99 percentile'); 10 Create geometry Using the Geometry Tools, click "Draw a shape". Using the Layer Manager, turn the visibility of layers off. Draw a shape that includes Georgia (6-7 vertices should be enough). Create vertices by left-clicking at different locations. Double left-click to close shape To leave the Geometry Tools, click the Exit button (right side of Geometry Tools) The geometry is added to the Imports section. Slow double click the geometry name to rename the geometry to georgia 11 Using reducers: by region NO FOR LOOPS //var daymetcollection = ee.imagecollection('nasa/ornl/daymet_v3'); // this won't work can't accumulate more than 5000 elements for printing //print(daymetcollection); // filters Daymet based on date (all images for 2015) and variable var filtereddaymetcollection = daymetcollection.filterdate(' ',' ').select(['tmax']); Sergio Bernardes, PhD 7

8 print(filtereddaymetcollection); // calculates maximum temperature for each pixel for 2015 var maxtemperature = filtereddaymetcollection.reduce(ee.reducer.max()); print(maxtemperature); Map.addLayer(maxTemperature,{min:25,max:40, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'max temp'); Map.setCenter(-83,36,8); // looking for rare events: calculates 99 percentile for each pixel for 2015 var percent99 = filtereddaymetcollection.reduce(ee.reducer.percentile([99])); print(percent99); Map.addLayer(percent99, {min:25,max:40, palette:['0000ff','00ffff','00ff00','ffff00','ff00ff','ff0000']},'99 percentile'); // calculates the maximum temperature for Georgia var maxtemp = maxtemperature.reduceregion({ reducer: ee.reducer.max(), geometry: georgia, scale: 1000, maxpixels: 1e9 }); print(maxtemp); 12 Save script Click Save button Enter path and file name: 00Workshop/Exercise02 Sergio Bernardes, PhD 8

9 Exercise 03: Load and process Landsat. Calculate NDVI and compute change analysis. Export results to Assets. 1 Clear script/ create new script 2 Add Marker (point) to Happy Valley, TN 3 Create geometry (point) (make sure you saved your previous script first) Click down arrow to the right of Reset button and then Clear script Use Search field to search for Happy Valley, TN. From the list of Places, click Happy Valley, TN to zoom into Happy Valley Using the Geometry Tools, click "Add a marker". Click anywhere to create a marker To leave the Geometry Tools, click the Exit button (right side of Geometry Tools) The geometry is added to the Imports section. Slow double click the geometry name to rename the geometry to happyvalley 4 Import Image Collection for Landsat 5 Surface Reflectance Use Search field to search for "landsat 5 surface" (no quotes) Select USGS Landsat 5 Surface Reflectance and inspect information (notice that bands include a cloud mask) Press import 5 Rename landsat collection 6 Try to print collection 7 We need to filter Filter using the geometry Check how many features are printed Slow double click the collection name to rename the collection to landsat5srcollection print(landsat5srcollection); // won't work (more than 5000 elements) //print(landsat5srcollection); // won't work (more than 5000 elements) // locate all Landsat 5 images that include happyvalley var filteredlandsat = landsat5srcollection ; print(filteredlandsat); Note: Geometry can be points, Sergio Bernardes, PhD 9

10 polygons or lines 8 We need to filter Filter using dates Check how many features are printed Dates can be single dates, months, years, or date ranges //print(landsat5srcollection); // won't work (more than 5000 elements) // locate all Landsat 5 images that include happyvalley var filteredbounds = landsat5srcollection ; print(filteredbounds); // locate all Landsat 5 images for a given date range var filtereddate = landsat5srcollection.filterdate(' ',' '); print(filtereddate); 9 Combining filters //print(landsat5srcollection); // won't work (more than 5000 elements) // locate all Landsat 5 images that include happyvalley var filteredbounds = landsat5srcollection ; print(filteredbounds); // locate all Landsat 5 images for a given date range var filtereddate = landsat5srcollection.filterdate(' ',' '); print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2011); 10 Cast collection into ee.image //print(landsat5srcollection); // won't work (more than 5000 elements) // locate all Landsat 5 images that include happyvalley var filteredbounds = landsat5srcollection ; Sergio Bernardes, PhD 10

11 print(filteredbounds); // locate all Landsat 5 images for a given date range var filtereddate = landsat5srcollection.filterdate(' ',' '); print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2011); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2011 = ee.image(filteredgeom2011); 11 Repeat the steps above for 2010 and comment previous code Display images without visualization parameters Use Layer Manager to explore what bands can be displayed and what min and max values can be. //print(landsat5srcollection); // won't work (more than 5000 elements) // // locate all Landsat 5 images that include happyvalley // var filteredbounds = landsat5srcollection // ; // print(filteredbounds); // // locate all Landsat 5 images for a given date range // var filtereddate = landsat5srcollection //.filterdate(' ',' '); // print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2011); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2011 = ee.image(filteredgeom2011); Sergio Bernardes, PhD 11

12 var filteredgeom2010 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2010); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2010 = ee.image(filteredgeom2010); Map.addLayer(imgFilteredGeom2010); Map.addLayer(imgFilteredGeom2011); 12 Add visualization parameters //print(landsat5srcollection); // won't work (more than 5000 elements) // // locate all Landsat 5 images that include happyvalley // var filteredbounds = landsat5srcollection // ; // print(filteredbounds); // // locate all Landsat 5 images for a given date range // var filtereddate = landsat5srcollection //.filterdate(' ',' '); // print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2011); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2011 = ee.image(filteredgeom2011); var filteredgeom2010 = landsat5srcollection.filterdate(' ',' ') Sergio Bernardes, PhD 12

13 print(filteredgeom2010); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2010 = ee.image(filteredgeom2010); // Map.addLayer(imgFilteredGeom2010); // Map.addLayer(imgFilteredGeom2011); // add visualization parameters and display images Map.addLayer(imgFilteredGeom2010, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2010'); Map.addLayer(imgFilteredGeom2011, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2011'); 13 Experiment modifying bands that are being displayed: use your code and Layer Manager 14 [Optional] Add ways for centering the map 15 Compute NDVI for 2010 Print image Inspect range for NDVI 'B4', 'B5', 'B3' 'B5', 'B4', 'B3' // options for centering map Map.centerObject(happyvalley, 12); Map.centerObject(filteredLandsat2010,12); //print(landsat5srcollection); // won't work (more than 5000 elements) // // locate all Landsat 5 images that include happyvalley // var filteredbounds = landsat5srcollection // ; // print(filteredbounds); // // locate all Landsat 5 images for a given date range // var filtereddate = landsat5srcollection //.filterdate(' ',' '); // print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') Sergio Bernardes, PhD 13

14 print(filteredgeom2011); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2011 = ee.image(filteredgeom2011); var filteredgeom2010 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2010); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2010 = ee.image(filteredgeom2010); // Map.addLayer(imgFilteredGeom2010); // Map.addLayer(imgFilteredGeom2011); // add visualization parameters and display images Map.addLayer(imgFilteredGeom2010, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2010'); Map.addLayer(imgFilteredGeom2011, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2011'); // Compute Normalized Difference Vegetation Index for 2010 var ndvi2010 = imgfilteredgeom2010.normalizeddifference(['b4','b3']); Map.addLayer(ndvi2010,{min:0,max:1},'ndvi2010'); print(ndvi2010); 16 Go ahead and compute NDVI also for 2011 //print(landsat5srcollection); // won't work (more than 5000 elements) // // locate all Landsat 5 images that include happyvalley // var filteredbounds = landsat5srcollection // ; // print(filteredbounds); // // locate all Landsat 5 images for a given date range // var filtereddate = landsat5srcollection //.filterdate(' ',' '); Sergio Bernardes, PhD 14

15 // print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2011); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2011 = ee.image(filteredgeom2011); var filteredgeom2010 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2010); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2010 = ee.image(filteredgeom2010); // Map.addLayer(imgFilteredGeom2010); // Map.addLayer(imgFilteredGeom2011); // add visualization parameters and display images Map.addLayer(imgFilteredGeom2010, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2010'); Map.addLayer(imgFilteredGeom2011, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2011'); // Compute Normalized Difference Vegetation Index for 2010 var ndvi2010 = imgfilteredgeom2010.normalizeddifference(['b4','b3']); Map.addLayer(ndvi2010,{min:0,max:1},'ndvi2010'); print(ndvi2010); // Compute Normalized Difference Vegetation Index for 2011 var ndvi2011 = imgfilteredgeom2011.normalizeddifference(['b4','b3']); Map.addLayer(ndvi2011,{min:0,max:1},'ndvi2011'); 17 [Optional] What if we wanted // Compute Normalized Difference Soil Index var ndsi2010 = imgfilteredgeom2010.normalizeddifference(['b5','b4']); Map.addLayer(ndsi2010,{min:0,max:1},'ndsi2010'); Sergio Bernardes, PhD 15

16 to compute NDSI as well? 18 Calculate and display change in NDVI from 2010 to 2011 print(ndsi2010); //print(landsat5srcollection); // won't work (more than 5000 elements) // // locate all Landsat 5 images that include happyvalley // var filteredbounds = landsat5srcollection // ; // print(filteredbounds); // // locate all Landsat 5 images for a given date range // var filtereddate = landsat5srcollection //.filterdate(' ',' '); // print(filtereddate); var filteredgeom2011 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2011); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2011 = ee.image(filteredgeom2011); var filteredgeom2010 = landsat5srcollection.filterdate(' ',' ') print(filteredgeom2010); // to make sure GEE sees this as an image we will cast var imgfilteredgeom2010 = ee.image(filteredgeom2010); // Map.addLayer(imgFilteredGeom2010); // Map.addLayer(imgFilteredGeom2011); // add visualization parameters and display images Map.addLayer(imgFilteredGeom2010, {'bands': ['B5', 'B4', 'B3'], 'min': 0, Sergio Bernardes, PhD 16

17 'max': 5000},'Landsat 2010'); Map.addLayer(imgFilteredGeom2011, {'bands': ['B5', 'B4', 'B3'], 'min': 0, 'max': 5000},'Landsat 2011'); // Compute Normalized Difference Vegetation Index for 2010 var ndvi2010 = imgfilteredgeom2010.normalizeddifference(['b4','b3']); Map.addLayer(ndvi2010,{min:0,max:1},'ndvi2010'); print(ndvi2010); // Compute Normalized Difference Vegetation Index for 2011 var ndvi2011 = imgfilteredgeom2011.normalizeddifference(['b4','b3']); Map.addLayer(ndvi2011,{min:0,max:1},'ndvi2011'); var ndvidifference = ndvi2011.subtract(ndvi2010); Map.addLayer(ndviDifference,{min: -0.3, max: 0.3, palette: ['FF0000','000000','00FF00']},'ndvi difference'); 19 [Optional] Cleaning results The code to the right can be added to the bottom of the script to clean results. // Let's clean results a bit by using cloud masks // get cloud masks from 2010 and 2011 var cfmask2010 = imgfilteredgeom2010.select('cfmask'); var cfmask2011 = imgfilteredgeom2011.select('cfmask'); // apply 2010 and 2011 masks to ndvidifference var maskedndvidifference = ndvidifference.updatemask(cfmask2010.lt(1)); var maskedndvidifference = maskedndvidifference.updatemask(cfmask2011.lt(1)); // also remove some residual values var maskedndvidifference = maskedndvidifference.updatemask(maskedndvidifference.lt(-0.10)); Map.addLayer(maskedNdviDifference,{min: -0.33, max: -0.1, palette: ['FF0000', 'FFFF00', '00FF00','00FFFF', '0000FF']},'ndviMasked difference'); print(maskedndvidifference); 20 [Optional] The code to the right can be added to the bottom of the script after cleaning results, to save results to Assets. // Export results to Assets Export.image.toAsset({ image: maskedndvidifference, description: 'deltandvi', assetid: 'users/sbernard/deltandvi', scale: 30 }); Sergio Bernardes, PhD 17

18 This may take a while to complete. 21 Save script Click Save button Enter path and file name: 00Workshop/Exercise03 Sergio Bernardes, PhD 18

19 Exercise 04: Load asset. Create geometry and buffer. Clip asset. 1 Clear script/ create new script 2 Load asset and rename it (make sure you saved your previous script first) Click down arrow to the right of Reset button and then Clear script Select the Assets tab and left-click the arrow to the right of deltandvi ("import into script") Slow double click the asset name to rename the asset to deltandvi 3 Display asset // display deltandvi Map.addLayer(deltaNDVI,{min: -0.33, max: -0.1, palette: ['FF0000', 'FFFF00', '00FF00','00FFFF', '0000FF']},'ndviMasked difference'); 4 Create line geometry Using the Geometry Tools, click "Draw a line". Create a line following the entire path of the tornado (two vertices should be enough) To leave the Geometry Tools, click the Exit button (right side of Geometry Tools) The geometry is added to the Imports section. Slow double click the geometry name to rename the geometry to "path" (no quotes) 5 Create a buffer of 4 km around path and display buffer // display deltandvi Map.addLayer(deltaNDVI,{min: -0.33, max: -0.1, palette: ['FF0000', 'FFFF00', '00FF00','00FFFF', '0000FF']},'ndviMasked difference'); var buffer = path.buffer(4000); Map.addLayer(buffer); 6 Centers map on buffer // display deltandvi Map.addLayer(deltaNDVI,{min: -0.33, max: -0.1, palette: ['FF0000', 'FFFF00', '00FF00','00FFFF', '0000FF']},'ndviMasked difference'); var buffer = path.buffer(4000); Map.addLayer(buffer); Map.centerObject(buffer); 7 Clip deltandvi using buffer and // display deltandvi Map.addLayer(deltaNDVI,{min: -0.33, max: -0.1, palette: ['FF0000', 'FFFF00', Sergio Bernardes, PhD 19

20 add result to map '00FF00','00FFFF', '0000FF']},'ndviMasked difference'); var buffer = path.buffer(4000); Map.addLayer(buffer); Map.centerObject(buffer); 8 Save script Click Save button var clippeddeltandvi = deltandvi.clip(buffer); Map.addLayer(clippedDeltaNDVI,{min: -0.33, max: -0.1, palette: ['FF0000', 'FFFF00', '00FF00','00FFFF', '0000FF']},'clipped'); Enter path and file name: 00Workshop/Exercise04 Sergio Bernardes, PhD 20

21 Some useful links: Google Earth Engine playground: Google Earth Engine developer's guide: GEE vector datasets: Tiles: Zoom levels: Julian day calendar: Sergio Bernardes, PhD 21

22 Examples of palettes: palette: ['FFFFFF', 'CE7E45', 'FCD163', '66A000', '207401'] palette: ['F4F0CB', 'BAA378', 'B3A580', 'FFF000', '00FF00'] palette: ['0000FF', '00FFFF', '00FF00', 'FFFF00', 'FF00FF', 'FF0000'] palette: ['FF0000', 'FF00FF', 'FFFF00', '00FF00','00FFFF', '0000FF'] palette: ['FF0000', '000000', '0000FF'] blue, cyan, green, yellow, magenta, red red, magenta, yellow, green, cyan, blue red, black, green Sergio Bernardes, PhD 22