calculating the NDVI with landsat data... manually

this is a long introduction into ndvi calculation. it´s also covering radiance and reflectance conversion as a preprocessing for ndvi calculation.

Category:

Science & Technology

Tags:

• NDVI
• Landsat
• remote sensing
• ETM
• TM
• reflectance
• radiance
• how-to
• tutorial

[MrAsabust]

I know that all information in the files *. mlt, but I can not find data BASIN and OFFSET. In my file *. mlt BASIN information is given except as "CPF" and not by the numerical information

[ricckli]

@MrAsabust would you mind to send me this file? riccardoklinger@gmail.com ....

[MrAsabust]

how to read the information needed to correct for the TM (Lλ = gain * QCAL + offset) , GAIN & OFFSET ??

[ricckli]

@MrAsabust normally each provider provides metadata for the scene. as for etm+ it is a so called met-file.

for TM you can find a MTL file.

this one serves as example: ftp://ftp.glcf.umd.edu/glcf/La­ndsat/WRS2/p134/r027/L5134027_­02720060810.TM-GLS2005/L513402­7_02720060810_MTL.txt

[nadi87s]

I was trying to calculate the NDVI of Evergreen forest patches of tropical region, but its showing only 0.4 to 0.6 for very good evergreen forest. slightly less for deciduous forest. But grasslands are having negative values. Once I did the atmospheric correction, Evergreen patch is having values between 0.72 and0.85. now some part of grasslands are still negative.. could you tell me why this happens?

[ricckli]

@nadi87s evergreen forest should be around 1 in nomral cases (there is some literature about the fact that the NDVI is not very good for evergreen forest: you normally get som saturation so it isn´t differentiating any more...). but unfortunately I don´t have any idea, which data you have used, probably you have used ERDAS to compute, have you used the inbuild function?

send me your answer on my gmail adress which you can find on google

[nadi87s]

I have mailed u the details. I used the Erdas Model builder.