diff --git a/src/FACT_elevation.jl b/src/FACT_elevation.jl
index c5f7942341b204f11e8c33e334e3dd2525e54b10..1f115a961e2badd99fc423a909c18d74860e4355 100644
--- a/src/FACT_elevation.jl
+++ b/src/FACT_elevation.jl
@@ -34,12 +34,12 @@ function elevation_data_full(ws_host_port::String, selection::Dict)
     
     for (id, shape) in zip(geo_id, shape_obj)
         # setting starting values to nothing
-        min_elevation = nothing
-        max_elevation = nothing
-        mean_elevation = nothing
-        std_elevation = nothing
-        median_elevation = nothing
-        entropy_elevation = nothing
+        min_elevation = -9999 #sentinel value
+        max_elevation = -9999 #sentinel value
+        mean_elevation = -9999 #sentinel value
+        std_elevation = -9999 #sentinel value
+        median_elevation = -9999 #sentinel value
+        entropy_elevation = -9999 #sentinel value
 
 
         # Construct the JSON payload
diff --git a/src/FACT_road.jl b/src/FACT_road.jl
index 88819f30cd7b353a7778a9fec5499edcbeb2342d..200bc3d9dce0761fb232257b85c12dc7020ea37f 100644
--- a/src/FACT_road.jl
+++ b/src/FACT_road.jl
@@ -49,7 +49,7 @@ function travel_time_in_minutes(ws_host_port::String, selection::Dict)
             # Construct the request URL
             url = "$ws_host_port/route/v1/driving/$(start_longitude),$(start_latitude);$(end_longitude),$(end_latitude)?overview=false"
 
-            travel_time = nothing  # Use `nothing` to represent null in Julia
+            travel_time = -9999 #sentinel value
 
             try
                 # Make the request