feat: read necessary grid prop from file

src/Fvcom.fs

@@ -344,6 +344,14 @@ let readBathymetry (ds: DataSet) =
         Log.Error e.Message
         Array.empty
 
+let tryReadBathymetry (ds: DataSet) =
+    if ds.Variables.Contains "h" then
+        ds[ "h" ].GetData()
+        :?> single []
+        |> Some
+    else
+        None
+
 let readBathymetryAtCenters (ds: DataSet) =
     let h = readBathymetry ds
     let lc = ds.Dimensions["nele"].Length
@@ -375,6 +383,14 @@ let readSiglev (ds: DataSet) n =
         Log.Error $"{err}"
         Array.empty
 
+let tryReadSiglev (ds: DataSet) n =
+    if ds.Variables.Contains "siglev" then
+        let l = ds.Dimensions["siglev"].Length
+        let siglev = ds[ "siglev" ].GetData([| 0; n |], [| l; 1 |]) :?> single [,]
+        Some siglev[*, 0]
+    else
+        None
+
 let readSiglay (ds: DataSet) n =
     try
         let l = ds.Dimensions["siglay"].Length
@@ -385,6 +401,14 @@ let readSiglay (ds: DataSet) n =
         Log.Error $"{err}"
         Array.empty
 
+let tryReadSiglay (ds: DataSet) n =
+    if ds.Variables.Contains "siglay" then
+        let l = ds.Dimensions["siglay"].Length
+        let siglay = ds[ "siglay" ].GetData([| 0; n |], [| l; 1 |]) :?> single [,]
+        Some siglay[*, 0]
+    else
+        None
+
 let readSiglevAtCenter (ds: DataSet) e =
     try
         let nv = ds[ "nv" ].GetData() :?> int [,] |> Array2D.map (fun n -> n - 1)
@@ -411,6 +435,18 @@ let readSiglayAtCenter (ds: DataSet) e =
         Log.Error $"{e}"
         Array.empty
 
+let tryReadSiglayAtCenter (ds: DataSet) e =
+    if ds.Variables.Contains "siglay" then
+        let nv = ds[ "nv" ].GetData() :?> int [,] |> Array2D.map (fun n -> n - 1)
+        let s1 = readSiglay ds nv[0, e]
+        let s2 = readSiglay ds nv[1, e]
+        let s3 = readSiglay ds nv[2, e]
+        [| 0 .. s1.Length - 1 |]
+        |> Array.map ( fun i -> (s1[i] + s2[i] + s3[i]) / 3.0f)
+        |> Some
+    else
+        None
+
 // deprecated
 let readSiglayCenter = readSiglayAtCenter
 
@@ -423,6 +459,14 @@ module Siglay =
             Log.Error $"{err}"
             Array2D.zeroCreate 0 0
 
+    let tryReadSiglay (ds: DataSet) =
+        if ds.Variables.Contains "siglay" then
+            ds[ "siglay" ].GetData()
+            :?> single [,]
+            |> Some
+        else
+            None
+
     let readSiglayAtCenter (ds: DataSet) =
         let siglay = readSiglay ds
         try
@@ -437,6 +481,13 @@ module Siglay =
             Log.Error $"{e}"
             Array2D.zeroCreate 0 0
 
+    let tryReadSiglayAtCenter (ds: DataSet) =
+        if ds.Variables.Contains "siglay" then
+            readSiglayAtCenter ds
+            |> Some
+        else
+            None
+
     let readUv (ds: DataSet) e t =
         try
             let l = ds.Dimensions["siglay"].Length
@@ -523,6 +574,7 @@ let getBBox (ds: DataSet) : BBox =
         BBox.empty
 
 let getGrid (ds: DataSet) : FvcomGrid =
+    printfn "getGrid"
     try
         let x =
             ds[ "x" ].GetData() :?> single []
@@ -538,10 +590,23 @@ let getGrid (ds: DataSet) : FvcomGrid =
             |> Array.map float
         let nv = ds[ "nv" ].GetData() :?> int [,]
 
-        let h = readBathymetry ds
-        let siglay = Siglay.readSiglay ds
-        let siglay_c = Siglay.readSiglayAtCenter ds
-        let siglev = ds[ "siglev" ].GetData() :?> single [,]
+        let h =
+            match tryReadBathymetry ds with
+            | Some b -> b
+            | None -> Array.empty
+        let siglay =
+            match Siglay.tryReadSiglay ds with
+            | Some s -> s
+            | None -> Array2D.zeroCreate 0 0
+        let siglay_c =
+            match Siglay.tryReadSiglayAtCenter ds with
+            | Some s -> s
+            | None -> Array2D.zeroCreate 0 0
+        let siglev =
+            if ds.Variables.Contains "siglev" then
+                ds[ "siglev" ].GetData() :?> single [,]
+            else
+                Array2D.zeroCreate 0 0
         let elem =
             Array.zip3 nv[0, *] nv[1, *] nv[2, *]
             |> Array.map (fun (a, b, c) -> a - 1, b - 1, c - 1)