Questions tagged [ndvi]
Normalized Difference Vegetation Index is used to quickly identify vegetation and its condition in remotely-sensed data.
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14 views
How to retrieve GIS data in Multiple Orthophoto at point level
I have been using a python script that can read Data from Orthophoto(*.tiff) of size 300Mb-2Gb. But this is taking 32s per request of lat-long, which is not ok.
I have different Orthophotos with ...
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1answer
19 views
Centroid value extraction of Landsat image collection in Google Earth Engine
I have an NDVI collection wich I have created from the combination of different collections Landsat5 and 7.
How can I exctract the NDVI values of the centroids of each pixel, of each image from my ...
2
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1answer
41 views
Calculate mean values for all bands and date to a dataframe
I have 5 rasters, each having 10 bands, where each band corresponds to a specific date.
How do I calculate mean values for all 10 bands and save them?
I need to save the mean values in a dataframe ...
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0answers
15 views
NDVI from SRGB image
I have a SRGB image from which I need to get the NDVI value.
I know how to calculate the NDVI, but it does not work with this SRGB image.
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1answer
15 views
How to determine the average NDVI value of a selected area?
I'm new to ArcMap 10.2 and trying to get NDVI data of city centers.
So my problem is, after I'm calculating the NDVI and getting the result raster, I would like to get a mean (average) value of ...
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1answer
30 views
Use Google Earth Engine to stack NDVI timeseries layers into one image and export
I would like to export the NDVI with the date in the filename in one image. Now I can only export them respectively.
And when I export the NDVI image, it shows the error "Error: Exported bands must ...
3
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1answer
46 views
Treatment of Landsat 7 SLC error in Google Earth Engine?
Google Earth Engine distributes Landsat 7 image composites of indeces such as NDWI and NDVI that, when averaged on a shapefile, give back a coherent value.
But how is SLC failure treated by it https:/...
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0answers
34 views
Nonlinear regression in Google Earth Engine on each pixel in an image collection using GEE's servers
I am attempting to optimize the parameters for a double-logistic function on an annual MODIS NDVI time series in Google Earth Engine. I have previously looked at Non Linear Regression in Google Earth ...
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1answer
55 views
Why does the raster calculator only give out 1 and 0 values
I have a problem with the raster calculator of ArcMap 10.5.1 because it only gives out a raster with 0 an 1 values. I'd like to calculate the Leaf Area Index out of a NDVI-Raster by using this ...
0
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1answer
47 views
Google Earth Engine equation
I want to write an equation for fractional vegetation in Google Earth Engine usisng NDVI.
My code is;
var ndviClip = ndvi.clip(table);
Map.addLayer(ndviClip, {min: -1, max: 1, palette: ['FF0000', ...
-1
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0answers
34 views
Classifying/extracting land cover types and getting percentages from raster image?
I have a rather large raster image and I want to classify land cover types in the image. Land cover types such as: developed land, Planted/cultivated, barren, forest, shrubland, and water. I am not ...
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1answer
44 views
r.mapcalculator
I am using QGIS 2.18.25. I'm struggling to use r.mapcalc to calculate the ndvi for a workbook project. R.mapcalculator is shown on the workbook I'm using and seems simpler to use. Is there a plug-in ...
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2answers
38 views
Faulty Landsat 5 and 7 NDVI/ EVI archives in Google Earth Engine
For my research, I need to use NDVI or EVI datasets in Google Earth Engine. I found Landsat 5 and 7 datasets (8 day, 32 day, anual) for both. However, no matter which combination of datasets and dates ...
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0answers
37 views
NDVI Python image showing inverse
I am trying to calculate NDVI using python and landsat imagery. I am able to calculate ndvi using the following equation:
def ndvi(sat, fp):
raster = rasterio.open(fp)
if sat.lower() == 'l8':
...
2
votes
1answer
102 views
Data smoothing of Sentinel-2 NDVI time series chart in Google Earth Engine?
I am exploring Sentinel-2 time-series NDVI with Google Earth Engine. In another post I learned how to plot a NDVI time series chart.
I know that there are many smoothing methods for reducing NDVI ...
0
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1answer
60 views
Setting values for palette in Google Earth Engine
I am very new to GEE. I have been trying to figure out how to assign different colours to different NDVI values. Let's say, in following code, I want to assign 'red' for NDVI value of 0.2-0.4, 'orange'...
3
votes
1answer
119 views
NDVI Scaling in Google Earth Engine?
I am trying to download NDVI data from the Google Earth Engine MODIS satellite. I used the following dataset:
img = ee.ImageCollection("MODIS/006/MOD13A2")
To actually download it, I ran img....
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0answers
19 views
What subset of bands would be most suitable for crop yield prediction?
I am working on a project to predict crop yield at district level from MODIS satellite data for India.
For that purpose I am choosing MODIS product MOD13A1 which provides vegetation indices at 500 m ...
0
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1answer
89 views
How do I convert Digital Number (DN) to reflectance in order to analyze NDVI
I'm working with a mapir nir + red camera meaning that its blue band captures nir light and its red captures red normally. I understand that NDVI is calculated using reflectance values. My question ...
1
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0answers
19 views
Error in smoothing NDVI (BISE) using SPIRITS
I want to minimize the spikes caused by cloud cover (smooth) NDVI timeseries data before applying Savitzky–Golay filter in Timesat. My previous post was also related to timeseries (Interpreting NDVI ...
0
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1answer
47 views
Image Collection minimum and maximum Extraction in Google Earth Engine?
I've wrote this code but it makes error about min and max image?
var modis = ee.ImageCollection("MODIS/006/MOD13Q1")
.filterBounds(geometry)
.filterDate("2000-01-01","2001-01-01")
.select("NDVI");
...
2
votes
1answer
288 views
Creating Sentinel-2 NDVI time series chart in Google Earth Engine?
I am exploring Sentinel-2 time-series NDVI with Google Earth Engine.
In another post (here) I calculated and exported NDVI values from Sentinel-2.
Now I would like to create a NDVI time series chart, ...
0
votes
1answer
28 views
How do I visualize NDVI values?
Currently, I have the NDVI values, and I transformed it from [-1, 1] to [0, 255]. Now my question is how do I visualize either of these value? My first thought is to make a color map similar to the ...
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1answer
171 views
Calculating NDVI per region, month & year with Google Earth Engine?
I want to calculate the mean NDVI per region (admin level 3, also called woreda), month and year. So my end result would look something like this:
regions year month NDVI
------------------...
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0answers
21 views
How to Write VCI index in Google Earth Engine? [duplicate]
How can I write this equation (NDVI - NDVImin) / (NDVImax - NDVImin) for modis ndvi image collection, could everyone help me please? I don't know, how can I extract min and max for each NDVI in image ...
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0answers
12 views
How extract image collection statistics with image image.reduceRegion in Google Earth Engine? [duplicate]
I am gonna to know that, how can I extract min and max of each image in this code? could everyone help me, please?
var modis = ee.ImageCollection("MODIS/006/MOD13Q1")
.filterBounds(geometry)
....
1
vote
1answer
51 views
Image Collection Statistics in Google Earth Engine?
How can I extarct mean of each image collection in google earth engine?
for example for this code:
var modis = ee.ImageCollection("MODIS/006/MOD13Q1")
.filterBounds(geometry)
.filterDate("2000-01-01",...
1
vote
2answers
94 views
Making stack from many images in Google Earth Engine?
Using the code below, I've computed 20 ndvi images for modis data.
How can I stack and save them in a single file?
var mod13 = ee.ImageCollection("MODIS/006/MOD13Q1")
.filterBounds(geometry)
....
0
votes
0answers
35 views
Monthly analysis of agri land with NDVI values using earth engine using UI. chart function in earth engine
I have tried to obtain monthly UI charts for NDVI values for a small field to understand the phenology of the crop. I am unable to generate the UI charts.
Link for the code in Earth Engine:
https://...
1
vote
0answers
9 views
Does Modis offer MultiYear statistics?
I'm trying to calculate the VCI data for my entire State.
I'm using MODIS's 16 day NDVI Average. From this post, I see that I would need to calculate the Min & Max NDVI values for each pixel ...
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1answer
37 views
EVI2 value calculated from MODIS MOD09Q1 not bounded by -1 to 1
I'm trying to derive from MODIS 8 day composite MOD09Q1.006 product
My formula follows the standard interpretation:
EVI2 = 2.5(NIR-Red)/(NIR + 2.4*Red+1)
I already know that MODIS bands for NIR ...
2
votes
1answer
121 views
GEE Export.image.toDrive output not matching bounding box?
I am new to GEE and javascript. Copy-pasting here and there, I managed to put together this code that extracts NDVI from cloud-free Sentinel-2 images on GEE. I created a fusion table from a KML with ...
0
votes
1answer
40 views
Classification based on NDVI values of two images
I want to find the areas where the NDVI value were higher then 0.4 at the end of April and NDVI values were lower then 0.3 at the end of June. I have tried to make it using below demonstrated script, ...
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0answers
12 views
USGS Landsat image: About pretreatment
According to USGS-Landsat T1 : All Tier 1 Landsat data can be considered radiometrically calibrated and geolocated consistently across the full collection for all the sensors.
So my question is, if ...
0
votes
1answer
43 views
Making subset of Sentinel-2 with rasterio?
I am looking for a solution to my problem with rasterio. I want to download just a specific part of the image from AWS based on lat lon coordinates. Rasterio offers a great tool (window) although it ...
0
votes
1answer
43 views
Is the resolution of MYD13A2/MOD13A2 ( MODIS 16 day 1km Global Vegetation Indices) erroneous in Google Earth Engine?
The MODIS vegetation indices collection shows a resolution of 111319.4 metres in Google Earth Engine when, in fact, it should be 1000 metres.
Below is my code:
var Veg = ee.ImageCollection("MODIS/...
0
votes
1answer
56 views
Incorporating NDVI and texture metrics in OBIA-Supervised Image Classification
Anyone knows step-by-step tutorials for incorporating NDVI and texture metrics in land cover classification with ArcMap?
I've been doing supervised classification of Sentinel-2 with the assistance ...
2
votes
0answers
68 views
Calculating indices such as NDVI or NDSI on Landsat 8 imagery whose pixel type is 16 bit signed integer?
I am trying to calculate an NDSI (Normalized Difference Snow Index) using Landsat 8 OLI level 1 imagery atmospherically corrected in ERDAS ATCOR using raster calculator in ArcMap. NDSI is used to to ...
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0answers
75 views
Interpreting NDVI curve in Timesat?
I am using 3 years of Modis(MOD13Q1) NDVI data in Timesat, I have selected a small portion of the forest area (fig.2) using processing window in TSM_GUI. As you can see that NDVI graph (blue_line) is ...
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0answers
212 views
Writing numpy array to rasterio raster file generates empty file
I'm using Rasterio to read GeoTIFF from Sentinel 2 and calculating NDVI, but when I try to save as a new TIF file, the file turns to transparent and empty file. What am I missing?
That's the code:
...
0
votes
1answer
128 views
Exporting an image of NDVI layers
I have calculated the NDVI for my study area. However, I am having challenges to export the NDVI images.
I want to export a single image with several NDVI layers. I have tried the mosaic function but ...
0
votes
1answer
37 views
Mosaic Landsat Scenes for NDVI Generation
I would Like to generate an NDVI map for my study region, which is positioned between three Landsat scenes.
Which method suits:
1) compute NDVI for each Landsat scenes and then mosaic or
2) Mosaic ...
0
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2answers
245 views
Google Earth Engine API: How to select an image from an image collection based on NDVI value?
I want to select the image with lowest median NDVI to represent bare ground cover from Sentinel-2 image collection for my region of interest (<5% cloud).
I have a boundary file pre-loaded on ...
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2answers
58 views
Distance measurement
I have calculated NDVI, now I would like to measure the distance from the places which have more vegetation concentration to low to bare concentration areas. which tool in ArcGIS 10.2 will be suitable ...
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votes
0answers
71 views
Dimensions of images given their latitude and longitude for Google Earth Engine
From the point
long: 16.499050771335575, lat: -30.882
I want to find the corresponding latitude and longitude values that would result in a 200 km by 200 km square in which the aforementioned ...
3
votes
1answer
99 views
Why vegetation index, NDVI or SAVI is not working in the desert?
Could anyone explain why the vegetation indices are not working in the desert region?
I used Landsat 8 image which has been already radiometric/atmospheric corrected.
I want to see the fractional ...
0
votes
0answers
33 views
Creating a Yearly Mean NDVI Layer with MOD13A2 Products
I would like to create a raster layer in ArcMap to show yearly (2011) mean NDVI values for the state of California, US with MOD13A2 products.
Should I consider the Day of year VI pixel layer when ...
1
vote
1answer
36 views
NDVI values to image conversion
I have a column of NDVI values of several centroid of pixels and relevant longitude/latitude associated with it.
I want to convert this table to a raster image in ArcGIS 10.4.1. I know the conversion ...
1
vote
0answers
66 views
Choosing statistical method for determining different crop types? [closed]
Task: Determining different crop types from satellite imagery.
Tools at hand
Training data set which includes RGB, longitude and latitude, NDVI
and crop type for each pixel (10m by 10m)
Test data ...
1
vote
1answer
220 views
Analyze time series NDVI using bfast
I would like to study a trend of NDVI data for a specific time interval using bfast package.
For this final aim, I read about the necessity to convert my data frame into a time series object in R. ...
