F# and ArcObjects, Part 3

Today i played a little bit with IFeature-sequences and piping data. The result was a calculator of the bounding box around all features in a feature class.
Maybe a little bit dirty, but for learning was it OK. ;-)
open System;;



#I "C:\Program Files\ArcGIS\DotNet";;

#r "ESRI.ArcGIS.System.dll";;

#r "ESRI.ArcGIS.DataSourcesGDB.dll";;

#r "ESRI.ArcGIS.Geodatabase.dll";;

#r "ESRI.ArcGIS.Geometry.dll";;

open ESRI.ArcGIS.esriSystem;;

open ESRI.ArcGIS.DataSourcesGDB;;

open ESRI.ArcGIS.Geodatabase;;

open ESRI.ArcGIS.Geometry;



let aoInitialize = new AoInitializeClass();;



let status = aoInitialize.Initialize(esriLicenseProductCode.esriLicenseProductCodeArcEditor);;



let workspacefactory = new SdeWorkspaceFactoryClass();;



let connection = "SERVER=okul;DATABASE=p*;VERSION=sde.default;INSTANCE=sde:sqlserver:okul;USER=s*;PASSWORD=g*";;



let workspace = workspacefactory.OpenFromString(connection, 0);;



let featureWorkspace = (box workspace) :?> IFeatureWorkspace;;



let featureCursorSeq (featureCursor : IFeatureCursor) = 

  let actualFeature = ref (featureCursor.NextFeature())

  seq {

    while (!actualFeature) <> null do
      yield actualFeature

      do actualFeature := featureCursor.NextFeature()

   };;



let min x y =

    if x < y then
        x

    else
        y;;



let max x y =

    if x > y then
        x

    else
        y;;



let info s (x : IEnvelope) =

    match x with
    | null -> printfn "%s is null" s

    | _ ->
        printfn "%s xMin:{%f} xMax: {%f} yMin:{%f} yMax: {%f}" s x.XMin x.XMax x.YMin x.YMax;;



let con (env1 : IEnvelope) (env2 : IEnvelope) =

    match env1 with
    | null -> env2

    | _ ->
        let env = (new EnvelopeClass()) :> IEnvelope

        env.XMin <- min env1.XMin env2.XMin

        env.XMax <- max env1.XMax env2.XMax

        env.YMin <- min env1.YMin env2.YMin

        env.YMax <- max env1.YMax env2.YMax

        info "Intermediate" env

        env

;;



let BoundingBox featureClassName = 

    let featureClass = featureWorkspace.OpenFeatureClass(featureClassName)



    let queryFilter = new QueryFilterClass()



    let featureCursor = featureClass.Search(queryFilter, true)



    let featureCursorSeq (featureCursor : IFeatureCursor) = 

      let actualFeature = ref (featureCursor.NextFeature())

      seq {

        while (!actualFeature) <> null do
          yield actualFeature

          do actualFeature := featureCursor.NextFeature()

       }



    featureCursorSeq featureCursor

    |> Seq.map (fun feature -> (!feature).Extent)

    |> Seq.fold (fun (acc : IEnvelope) a ->
        info "Intermediate" acc

        (con acc a)) null
;;



let boundingBox = BoundingBox "Praxair.SFG.BP_L_ROHR";;

info "Ende-Info:" boundingBox;;