diff --git a/R/SAPA.R b/R/SAPA.R
index 755eed8..760900b 100644
--- a/R/SAPA.R
+++ b/R/SAPA.R
@@ -119,7 +119,7 @@ SAPA<- function(r=NULL, w = 1, slope_correction=TRUE, na.rm=FALSE, include_scale
   } # Sum up surface area in focal window (or scale mean to number of cells)
   
   if(is.null(slope_layer) & slope_correction){
-    if (all(w==1)){
+    if (all(w==1) & (!na.rm)){
       slope_layer<- terra::terrain(r, v="slope", unit="radians", neighbors=8, wopt=wopt)
       } else{
         slope_layer<- SlpAsp(r, w=w+2, unit="radians", method="queen", metrics= "slope", na.rm=na.rm, include_scale=FALSE, wopt=wopt)
diff --git a/README.md b/README.md
index 0ac1ec1..87176a8 100644
--- a/README.md
+++ b/README.md
@@ -1,7 +1,7 @@
 README
 ================
 Alexander Ilich
-September 12, 2023
+December 30, 2023
 
 # MultiscaleDTM
 
@@ -279,7 +279,7 @@ vrm<- VRM(r, w=c(5,5), na.rm = TRUE)
 ![](man/figures/README-VRM-1.png)<!-- -->
 
 ``` r
-sapa<- SAPA(r, w=c(5,5), slope_correction = TRUE)
+sapa<- SAPA(r, w=c(5,5), slope_correction = TRUE, na.rm=TRUE)
 ```
 
 ![](man/figures/README-SAPA-1.png)<!-- -->
diff --git a/man/fragments/README_Frag.Rmd b/man/fragments/README_Frag.Rmd
index d75dc1b..4337f27 100644
--- a/man/fragments/README_Frag.Rmd
+++ b/man/fragments/README_Frag.Rmd
@@ -248,7 +248,7 @@ tm_shape(vrm, raster.downsample = FALSE)+
 ```
 
 ```{r}
-sapa<- SAPA(r, w=c(5,5), slope_correction = TRUE)
+sapa<- SAPA(r, w=c(5,5), slope_correction = TRUE, na.rm=TRUE)
 ```
 
 ```{r SAPA, echo=FALSE}