F# and ArcObjects, Part 3
- by Marko Apfel
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 featureClass = featureWorkspace.OpenFeatureClass("Praxair.SFG.BP_L_ROHR");;
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()
};;
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) =
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) =
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 feature = featureClass.GetFeature(100);;
let ext = feature.Extent;;
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)) ext
;;
let boundingBox = BoundingBox "Praxair.SFG.BP_L_ROHR";;
info "Ende-Info:" boundingBox;;
