All Questions
22 questions
-1
votes
1
answer
1k
views
Interpreting Green Chlorophyll Index vs NDVI
I am attempting to research the relationship between agricultural yields and household well-being, and I am using remote sensed vegetation indices calculated from LANDSAT images to do this. Whereas ...
- 93
4
votes
2
answers
909
views
Landsat 8 appears to be "greener" than Landsat 5?
I noticed something strange in my NDVI time series. Here I plotted NDVI for some geometries of interest in European countries between 1985 and 2020.
You will see there is a noticeable jump in NDVI ...
- 87
3
votes
3
answers
2k
views
Issue with scaling factors for Landsat Collection 2 Level 2 data when calculating NDVI
I'm trying to calculate the NDVI for a scene, and I've downloaded Landsat 8 OLI/TIRS Collection 2 Level 2 data, which means it has already been processed to surface reflectance.
The scaling factors ...
- 31
2
votes
1
answer
493
views
Exporting EVI image on Google Earth Engine with visual parameters between -1 and 1?
I am having an issue with exporting an EVI image with the visual parameters between -1 and 1. On Google Earth Engine (GEE), using the inspector tool, the values are between -1 and 1, but when I export ...
- 21
1
vote
0
answers
48
views
The emissivity of snow
I try to use the NDVI Based Emissivity Method to calculate the LSE. But the function almost applied over surfaces composed by soil and vegetation. Over surfaces like water, ice, or snow did not ...
- 31
0
votes
1
answer
184
views
Produce NDVI on Landsat1 satellite images?
Does someone have any experience to produce NDVI on the Landsat1 satellite image? What kind of atmospherical correction (on Landsat 1) technique is necessary to perform before producing indices? Is it ...
1
vote
1
answer
730
views
Landsat level-2 NDVI valid range with saturation
I have Landsat level-2 NDVI tiles I am using in ArcMap 10.4.1.; however, the level-2 NDVI data in ArcMap ranges from -5,189 to +20,000.
The spectral image product guide (which I've linked) says that ...
- 425
2
votes
1
answer
450
views
Landsat Collection 1 Level-1 or Landsat Collection 1 Higher Level?
I want to use NDWI and NDVI index in my study for a time-series analysis using all products available (Landsat 5,7 and 8).
Can I use the product Landsat Collection 1 Level 1 for my analysis or
...
- 41
1
vote
1
answer
1k
views
calculate NDVI for several images
I want to calculate NDVI for 50 Landsat 7-TM images . I have done a stack layer for each band of 50 images using envi software and then calculate NDVI for the stack of two bands demanded in NDVI ...
- 19
10
votes
1
answer
1k
views
Landsat level-2 data comparison
I'm doing a temporal analysis of NDVI and temperature over 17 years, necessitating data from Landsat 5,7, & 8. I'm interested in using level-2 Landsat data available from https://espa.cr.usgs.gov/...
- 425
3
votes
1
answer
869
views
Better NDVI for Landsat 8?
I'm looking at NDVI changes for an area over 20 years. There seems to be a slight downward trend, however, upon switching from Landsat 5 in 2011 to Landsat 8 in 2013 I'm getting NDVI values that are ...
- 147
1
vote
2
answers
1k
views
Using ArcGIS Raster Calculator to calculate MSAVI2 based on Landsat 8 OLI bands 4 and 5
I would like to calculate a Modified Soil-Adjusted Vegetation Index 2 on the basis of Landsat 8 OLI imagery, bands 5 (NIR) and 4 (RED), using the Raster Calculator. The formula should be:
I have ...
- 11
2
votes
2
answers
451
views
Comparability of Landsats
I have collected data (spectral bands) from Landsat 4-5 and Landsat 8. I was calculating NDVI when I noticed that the two Landsats have different band numbers designated as Red and Near Infra Red (...
- 736
7
votes
1
answer
5k
views
Difference between Landsat 7 and Landsat 8 TOA reflectance computation
In section 3.1 of this article it is explained how the Top of Atmosphere Reflectance for Landsat 7 and Landsat 8 are computed. The equation for Landsat 8 is not mentioned explicitly, but can be found ...
- 901
4
votes
2
answers
2k
views
Classify forest with NDVI from Landsat 8 and 7
I'd like to calculate the NDVI for multi-date satellite images of Landsat (7,8) to perform a change detection on the deforestation of the Amazon rainforest. I already acquired surface reflectance ...
- 55
3
votes
2
answers
4k
views
Tutorial Vegetation Condition Index
Anybody here can help me regarding calculating Vegetation Condition Index (Kogan,2004) for Landsat?. Specially facing problem in NDVI_max and NDVI_min; which should be maximum and minimum value?
- 105
5
votes
1
answer
454
views
Determining the best month for discriminating between different vegetation types?
I ordered and downloaded several (Surface Reflectance) Landsat 5-8 images from USGS Earth Explorer with the purpose of choosing a few of them to calculate some Vegetation Indices for each (NDVI, SAVI, ...
- 313
3
votes
1
answer
2k
views
Is atmospheric correction necessary when working with multi-spectral indexes?
When you are working with Landsat Level 1 data and calculate indexes, e.g. NDVI, NDBI, SAVI ..., do you calculate them using raw data (pixel DN value), or atmospherically corrected data (surface ...
- 423
2
votes
1
answer
1k
views
How to interpret Tasseled Cap Greenness for Landsat 5?
I have amassed a few promising literature articles, and looked at the help files for ENVI, ArcMap and PCI, and no one really goes into great depth on how to interpret spectral values for Tasseled Cap ...
- 89
4
votes
2
answers
1k
views
Classification, Change detection and NDVI Using (landsat2 MSS), (landsat5 TM), (Landsat7 ETM+) and (Landsat8 OLI)
I have 5 Landsat images for the same study area. One of them in 1975 (Landsat 2 MSS), two in 1985 and 1995 (Landsat 5 TM) and one in 2005 (Landsat 7 ETM+) and the last one in 2014 (Landsat8 OLI). I ...
- 69
3
votes
2
answers
2k
views
Calculating NDVI using Landsat ETM+ band values
I have sample points (shape file converted from a .xls file which contains XY coordinates,nnx,nny and canopy density) and a landsat etm+ image. First I applied 'SpatialAnalyst Tools>Extraction >Sample'...
- 197
2
votes
0
answers
365
views
Change Detection ArcGIS with multiple dates
I'll explain my aim first: I am trying to create a single raster to represent vegetation resilience, I am doing this via change detection.
So far I have created 5 Change detection images, where 2000 ...