Wednesday, May 31, 2017

Prevent WPF Global Keyboard Hook from stops working after hitting keys a while C# .NET

Be The First To Comment
The article written by Dylan Currier, Low Level Global Keyboard Hook / Sink in C# .NET is one the simple, easily understandable, and and working post on Global Keyboard hook out there in internet. It worked in my WPF application and I added following line in the WPF app to refresh hook after each key press- IDK  if it is write or wrong, more likely to be a wrong practice to hook/unhook every time but it gets the job done. The primary reason to refresh hook is to prevent app hanging (not responding to the key press) after few clicks on the WPF button.

void _listener_OnKeyPressed(object sender, KeyPressedArgs e)

Following is the video from Dylan Currier  on Low Level Keyboard Hook in C# / .NET"

Wednesday, May 24, 2017

When to use ArcGIS Online to publish geospatial data: CASE STUDY EUROPEAN ENVIRONMENT AGENCY

Be The First To Comment
ArcGIS Online is a workspace and a web platform for creating and sharing maps. It is possible to upload your data, create a layer or a map, define the extent, set some visualization options, assign permissions to your layer or map, share, and create web mapping applications or story maps. For information about the other capabilities please visit

The ArcGIS online platform is designed to host small datasets, for example demographic datasets. The datasets uploaded to ArcGIS online are relatively small in size, and should not exceed 1-2MB, or around 5000 records. This is to keep the agencies costs down and keep in line with our ArcGIS online pricing plan. It is for this reason that ArcGIS online should not be used to host large datasets, and tiled image services must NOT be uploaded to ArcGIS online. To publish bigger datasets and image services, please refer to the ArcGIS Server.


Wednesday, May 17, 2017

Code snippet: Identify to which polygon a point belong to?

Be The First To Comment
Code sample to find point inside a polygon in shape file using GDAL/OGR 2.x and C#.

using OSGeo.OGR;
using OSGeo.OSR;
using OSGeo.GDAL;
1:  public void FindPolygonBelongsToPoint()   
2:      {  
3:        try   
4:        {  
5:          var shapePath = @"C:\Locations_WGS84.shp";  
6:          Ogr.RegisterAll();  
7:          OSGeo.OGR.Driver shapeDriver = Ogr.GetDriverByName("ESRI Shapefile");  
8:          DataSource shape = shapeDriver.Open(shapePath, 0);  
9:          Layer layer = shape.GetLayerByIndex(0);  
11:          Feature polygonFeature = layer.GetNextFeature();  
13:          long featureCountInLayer = layer.GetFeatureCount(1);  
14:          for (int i = 1; i <= featureCountInLayer; i++) {  
16:            Geometry polygonGeom = polygonFeature.GetGeometryRef();  
18:            string coordinates = "POINT (-100.726 38.995)";  
20:            SpatialReference spatialRef = layer.GetSpatialRef();  
21:            Geometry point = Ogr.CreateGeometryFromWkt(ref coordinates, spatialRef);  
23:            bool isInside = point.Within(polygonGeom);  
25:            if (isInside)  
26:            {  
27:              var val = polygonFeature.GetFieldAsString(4);  
28:              Console.WriteLine("Found one");  
29:            }  
31:            polygonFeature = layer.GetNextFeature();            
32:          }         
34:        }  
35:        catch (Exception ex)   
36:        {  
38:          Console.WriteLine(ex.Message);  
39:        }          
41:      }  

Tuesday, May 2, 2017

Code snippet: To highlight selected feature in ArcMap programmatically using ArcObjects

Be The First To Comment
Code snippet to highlight selected feature in ArcMap programmatically using ArcObjects and return the STGeomFromWKB   string of selected feature.

To return the geometry you should import Microsoft.SqlServer.Types  from Nuget and SqlServerSpatial140.dll  from C:\Windows\System32

 using System;  
 using System.Collections.Generic;  
 using System.Data.SqlTypes;  
 using System.Linq;  
 using System.Runtime.InteropServices;  
 using System.Text;  
 using System.Windows;  
 using ESRI.ArcGIS.ArcMapUI;  
 using ESRI.ArcGIS.Carto;  
 using ESRI.ArcGIS.Catalog;  
 using ESRI.ArcGIS.CatalogUI;  
 using ESRI.ArcGIS.Desktop.AddIns;  
 using ESRI.ArcGIS.Display;  
 using ESRI.ArcGIS.esriSystem;  
 using ESRI.ArcGIS.Framework;  
 using ESRI.ArcGIS.Geodatabase;  
 using ESRI.ArcGIS.Geometry;  
 using Microsoft.SqlServer.Types;  
 namespace Test.Addin.ArcCommands  
   class SelectFeatureTool : ESRI.ArcGIS.Desktop.AddIns.Tool  
     protected override void OnMouseDown(MouseEventArgs arg)  
       IMxDocument mxDocument = ArcMap.Application.Document as IMxDocument;  
       IActiveView activeView = mxDocument.ActiveView;  
       IMap map = mxDocument.FocusMap;  
       ILayer layer = map.get_Layer(0); //Get 1st Layer  
       IFeatureLayer featureLayer = (IFeatureLayer) layer;  
       IPoint identifyPoint = activeView.ScreenDisplay.DisplayTransformation.ToMapPoint(arg.X, arg.Y);  
       ESRI.ArcGIS.Carto.IIdentify identifyLayer = (IIdentify)layer;  
       IArray array = identifyLayer.Identify(identifyPoint);  
       int oid = -1;  
       if (array != null)  
         object obj = array.get_Element(0);  
         IFeatureIdentifyObj fobj = obj as IFeatureIdentifyObj;  
         IRowIdentifyObject irow = fobj as IRowIdentifyObject;  
         IFeature feature = irow.Row as IFeature;  
         oid = feature.OID;  
       HighlightClickedFeature(featureLayer, oid, activeView);  

Python code snippet : Merge multiple CSVs (Column Wise) into a large CSV file using ID

Be The First To Comment
Following is the python code snippet to merge multiple CSVs into a large CSV (column wise) using CSV's unique ID field. All input CSV's must have same length.

 import csv
 import itertools
 outCombinedStatTxtName ="FormattedTxtResults.csv"  
 tempCsvFiles = glob.glob(str(TempFolderPath)+'\*.csv')  
 openedFileList = [open(fn, 'rb') for fn in tempCsvFiles]  
 readers = [csv.reader(fn) for fn in openedFileList]  
 result = open(outCombinedStatTxtName, 'wb')  
 writer = csv.writer(result,delimiter=',')  
 multipleIndices = False  
 for row_chunks in itertools.izip(*readers):  
   tempFormattedRow = list(itertools.chain.from_iterable(row_chunks))  
   fidIndices = [i for i, x in enumerate(tempFormattedRow) if x == "ID"]  
   if(len(fidIndices) > 1):  
     redundantIndices = tuple(fidIndices)  
     multipleIndices = True  
     tempFormattedRow = [ tempFormattedRow[i] for i in xrange(len(tempFormattedRow)) if i not in set(redundantIndices) ]      
 [fn.close() for fn in openedFileList]  


© 2011 GIS and Remote Sensing Tools, Tips and more .. ToS | Privacy Policy | Sitemap

About Me