Apparent reflectance function in ArcGIS does not generate surface reflectance. It generates top-of-atmosphere reflectance using gain/bias coefficients, earth-sun distance, and solar irradiance. Surface reflectance must be derived from a radiative transfer model, ground collected spectra, or scene based technique such DOS or empirical model like QUAC.
@GEO2004
7 жыл бұрын
whatever dude. there are two ways of how we deal with atmospheric effects in radiometric correction, physical based or empirical based, what are you saying is physical,and sometimes the perquisites data are hard to obtain, what I post here is empirical based, just like dark object substraction or any similar techniques, and yes it can be considered as atmospheric correction too,
@AlcantaraEH
6 жыл бұрын
No, what you've done is not a atm correction, such as the DOS. As Sean wrote, what you've got is the apparent reflectance. You just apply the reflectance conversion equation using pi, d2, L, etc..Please, be so kind and rename you video.
@ArianaGrandeFan
5 жыл бұрын
How to rescale the image after reflectance Bcz when I try to classified it give not correct result as compare to raw data.
@GEO2004
5 жыл бұрын
Usually, reflectance product is dedicated as input for soft classification like spectral unmixing or spectral angle mapper. If you think rescale is your preferable option, you can use reclase tool available in arcgis or qgis, for arcgis the tool can be found in spatial analyst toolbox
@SohaAhmed-tx6sz
7 жыл бұрын
Incredible
@fredisatya8747
5 жыл бұрын
TOA Reflectance sepertinya Mas Juk. Anyway, thanks for the tutorials. Salut aku njenengan isih nduwe wektu nggo nggawekke tutorial sing membutuhkan.
@GEO2004
5 жыл бұрын
Seperti yang tak jelasin ke berbagai orang, yang mengklaim surface reflectance adalah softwarenya, masalah apakah benar TOA atau surface, pertimbangan parameternya bisa banyak banget. Full surface reflectance kayak modtran, flaash, atau 5S/6S parameternya susah (sebagian cuma asumsi malah), Beberapa bule ngeyeli tetep itu masuk TOA, ya silahkan saja. Dark object substraction tidak bisa diterima sebagai koreksi atmosfer juga silahkan.
@fredisatya8747
5 жыл бұрын
@@GEO2004 Apparent Reflectance Function di ArcMap itu ada 2 function yang dipakai: 1. DN to TOA Radiance 2. TOA Radiance to Apparent Reflectance, based on sun elevation and acquisition date. Nah, fungsi ke dua itu baru merubah radian at sensor ke Reflectance at sensor, kemudian disusul dengan koreksi posisi dan sudut matahari. Jadi hasilnya adalah koreksi Top Of Atmosphere Reflectance Mas. Setelah itu, langkahnya baru koreksi atmosphere salah satunya bisa dark of subs, atau dengan lain2nya. Dark of subs memang hanya salah satu pendekatan saja, tidak benar juga. Namun, karena paling mudah dilakukan jadi pada pakai DOS itu.
@@fredisatya8747 dilihat saja deskripsi raster functionnya, disitu disebut apparent surface reflectance
@debaleenamajumdar6473
5 жыл бұрын
Can anyone please tell me how to generate bottom reflectance of sea water from LANDSAT image
@GEO2004
5 жыл бұрын
Will do that when I have the spare time
@azkas4564
7 жыл бұрын
hi.. can i ask why my metadata cnnot be read by GIS..
@GEO2004
7 жыл бұрын
azka S which version you are using? landsat 8 metadata can be opened properly since arcgis version 10.3, the previous version wont read it well, so consider to upgrade your arcgis to newest release
@alexandercarles5121
3 жыл бұрын
Sepurane mas , untuk landsat 7 bisa dengan metode ini kah mas? Terimakasik
@GEO2004
3 жыл бұрын
Bisa,
@alexandercarles5121
3 жыл бұрын
Makaasih mas 🙏
@kevinb.8279
7 жыл бұрын
Audio!!!
@GEO2004
7 жыл бұрын
aww hell, no,
@Bastuun
7 жыл бұрын
I have to ask to what degree this is a credible method for estimating surface reflectance? seems like too easy of a switch-a-roo for it to be scientifically credible. push two buttons and voila! surface reflectance galore!
@GEO2004
7 жыл бұрын
This is just a method, besides any other methods, which is ranging from simple to complicated one. there is theoretical explanation behind this method, I suggest you to read them to know does it scientifically credible or not. Unless you are the kind of "more complex better results" guy. I just cant help it.
@Bastuun
7 жыл бұрын
I'm a total fan and user of the happy go lucky attitude in general, but when doing things, from which effects follow, the consequences of which affect a whole lot of other people, I would argue that being "a more complex, better results type of guy" is the only way out. But you certainly have my attention, I will read up on this method.
@GEO2004
7 жыл бұрын
hahaha no hard feelings dude, then lets just try it and perform an assessment by yourself, compare it to more sophisticated or more rigorous one, Personally, I dont believe a better or more complex method will guarantee better result in remote sensing. Its all depend on accuracy assessment. Imagine if we dont have anciliary data to perform proper atmospheric correction (visibility, water vapour, etc, you name it), where will we go ?
@AlcantaraEH
6 жыл бұрын
Whatever, calling this "surface reflectance" is an offense to science. Please, rename your video to apparent reflectance! Some students may think that you're correct! Dude.
@GEO2004
5 жыл бұрын
I just read your comment, guess you are right, going to rename it. Esri has changed the raster function name at recent version, thx
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