Error in calcAnchors(image = image.TOAr, Ts = Ts, LAI = LAI, plots = T, : Not enough pixels with the conditions for anchor pixels. I found 0 cold pixels and 0 hot pixels.

[Omar87senjar]

I have challenges with the Energy Balance calculation of the water package, following the example code found on: https://cran.rproject.org/web/packages/water/vignettes/Landsat8.html. Using my own data, I read my original landsat image and the surface reflectance image with my area of interests (aoi). But, I get the following error when I use this code.

Energy.Balance <- METRIC.EB(image.DN = image_band, image.SR = image_SR_band,
plain = TRUE, aoi = aoi, n = 5,
WeatherStation = WeatherStation, ETp.coef = 1.2, sat = "L8",
alb.coeff = "Olmedo", LST.method = "SW",
LAI.method = "metric2010", thermalband=image.DN$thermal.low,
Z.om.ws = 0.03, anchors.method = "flexible", MTL = MTLfile)

Error in calcAnchors(image = image.TOAr, Ts = Ts, LAI = LAI, plots = T, :
Not enough pixels with the conditions for anchor pixels. I
found 0 cold pixels and 0 hot pixels.
In addition: Warning messages:
1: PROJ support is provided by the sf and terra packages among others
2: In calcAnchors(image = image.TOAr, Ts = Ts, LAI = LAI, plots = T, :
anchor method names has changed. Old names (CITRA-MCBx) are
deprecated. Options now include 'best', 'random' and 'flexible'
3: In max(Ts[albedo >= 0.13 & albedo <= 0.15 & NDVI >= 0.1 & NDVI <= :
no non-missing arguments to max; returning -Inf

[raushal1]

I also ran into a similar problem. Mine says, "found 0 cold pixels and 14 hot pixels". Please let me know if you figured it out somehow.

[raushal1]

@midraed Can you please take a look at this, sir? What do you think might have caused this error?

[Omar87senjar]

if i solve the problem, i will inform you.

[raushal1]

Thanks a lot.
Also, sir, is there a way to get in touch with you? Maybe your linkedin? I would like to discuss some issues that I am facing with the code and see if you are facing similar issues?

[Omar87senjar]

Ok no problem. https://www.linkedin.com/in/omar-alsenjar-6431aaa0/. You can send me message to my account.
With all respect

[ishwar97]

Hey @Omar87senjar and @raushal1,
I also faced similar issue when I was working with water package. It is necessary for algorithm to find at least one hot and cold pixel per scene to run successfully. Sometimes, it is not possible to find one pixel each for hot and cold conditions as per the criteria cited in https://journal.r-project.org/archive/2016/RJ-2016-051/RJ-2016-051.pdf.
I found a work around to it by changing the script of function calcAnchors and manipulating the flexibility limits to find at least one hot and cold pixel.
Hope this helps!