Compute zonal statistics on area of interest polygon on fly

Draft to compute zonal statistics on area of interest polygon or shape draw on leaflet using PostgreSql and Java -

Geometry extracted from leaflet as GeoJson.

Polygon-
{"type":"Feature","properties":{"desc":null,"image":null},"geometry":{"type":"Polygon","coordinates":[[[-117.103271484375,34.264026473152875],[-117.1142578125,34.14818102254435],[-117.03186035156251,34.10498222546687],[-116.91925048828124,34.14363482031264],[-116.94946289062499,34.25494631082515],[-117.0867919921875,34.252676117101515],[-117.103271484375,34.264026473152875]]]}}


{"type":"Feature","properties":{"desc":null,"image":null},"geometry":{"type":"Polygon","coordinates":[[[-116.86981201171875,34.11407854333859],[-116.86981201171875,34.24132422972854],[-116.71874999999999,34.24132422972854],[-116.71874999999999,34.11407854333859],[-116.86981201171875,34.11407854333859]]]}}

Point-
{"type":"Feature","properties":{"desc":null,"image":null},"geometry":{"type":"Point","coordinates":[-116.9879150390625,34.048108084909835]}}

Area of GeoJson

Select (ST_Area(ST_GeomFromText

('POLYGON ((-117.16918945312501 34.27083595165,-117.1307373046875 34.166363384737892,-117.00988769531251 34.161818161230386,-116.93298339843751 34.239053668516412,-116.98516845703126 34.27083595165,-117.16918945312501 34.27083595165))',4326)))

Zonal statistics for each raster tile -

SELECT rid, (ST_SummaryStats (ST_Clip(rast,ST_GeomFromText('POLYGON ((-117.16918945312501 34.27083595165,-117.1307373046875 34.166363384737892,-117.00988769531251 34.161818161230386,-116.93298339843751 34.239053668516412,-116.98516845703126 34.27083595165,-117.16918945312501 34.27083595165))',4326),true))).*
FROM public.biodiv_ssolnw_wgs84
WHERE ST_Intersects
(rast,ST_GeomFromText
('POLYGON ((-117.16918945312501 34.27083595165,-117.1307373046875 34.166363384737892,-117.00988769531251 34.161818161230386,-116.93298339843751 34.239053668516412,-116.98516845703126 34.27083595165,-117.16918945312501 34.27083595165))',4326))
Group By rid

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Quick cheat-sheet on Angular/cli

Quick cheat-sheet on Angular/cli to generate boiler plate codes.

Install Angular/cli
npm install –g @angular/cli

Check Agnular/cli version
ng –v
        or
npm list –g  @angular/cli --depth=0

Generate  files without installing it
ng new ng2CliApp --skip-install

Create new project with out writing the files in but report them commandline console
ng new ng2CliApp --dry-run

Create new project with app prefix
ng new ng2CliApp --prefix coolapp --dry-run

Create new project without test files
ng new ng2CliApp  --skip-tests --prefix cool_ng2CliApp --dry-run

Create new project with style-sheets
ng new ng2CliApp --skip-tests --prefix cool_ng2CliApp --style scss 

Create new project with Routing
ng new ng2CliApp --routing --skip-tests --prefix cool_ng2CliApp --style scss --skip-install

Create new Component
ng g component my-new-component

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Solved: Cannot connect Postgre in VM from host

Used vagrant for setting up the VM, so set private network and port forward in vagrant file as below -
               
                 migration.vm.network "private_network", ip: "192.168.33.10"
                 migration.vm.network "forwarded_port",guest:5432 , host:15432 


1. Use telnet localhost 15432 to see if the port is open (Host)


Still can not connect to PostgresSql running in VM  :(

Then

2. Edit postgresql.conf (Guest)
#------------------------------------------------------------------------------
# CONNECTIONS AND AUTHENTICATION
#------------------------------------------------------------------------------

# - Connection Settings -

           listen_addresses = '*'


3.  Add following in pg_hba.conf

# IPv4 local connections:
host    all             all             127.0.0.1/32            md5
host    all              all            0.0.0.0/0               md5


4. Finally, able to connect to Postgres via localhost:15432

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Getting started with Raster and PostGIS - I

Steps for loading a raster in PostGIS (PgSql 9.4/ PostGIS 2.2) and pull it from database to view in QGIS 2.14.17.

1. Generate SQL for raster [NOTE: Do not create PostGIS table name starts with underscore, it creates problem while adding raster to QGIS from PostGIS database using DB Manager]

        raster2pgsql -s 4326 -I -C -M -F -t 50x50 -N nan biodiv_ssolnw.tif > biodiv_ssolnw.sql

2. Import generated raster into PostGIS database [Make sure to enable postgis extension in db]

         psql -h localhost -U postgres -d ecolservicedb -f biodiv_ssolnw.sql

the output is:
Processing 1/1: ags_473038164.tif
BEGIN
CREATE TABLE

INSERT 0 1
INSERT 0 1
INSERT 0 1
INSERT 0 1
…
…
….
CREATE INDEX
ANALYZE
NOTICE:  Adding SRID constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding scale-X constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding scale-Y constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding blocksize-X constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding blocksize-Y constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding alignment constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding number of bands constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding pixel type constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding nodata value constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding out-of-database constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
NOTICE:  Adding maximum extent constraint
CONTEXT:  PL/pgSQL function addrasterconstraints(name,name,name,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean,boolean) line 53 at RETURN
 addrasterconstraints
----------------------

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Setup Jenkins Bit-bucket environment in Windows Server 2008

Steps for setting Jenkins/Bitbucket CI environment in Windows - little trickier than Linux

1) Download and Install Jenkins-2.60.1(current as of the day written)

2) Once installed changed the port from C:\Program Files (x86)\Jenkins\jenkins.xml to ‘9090’ and
restart jenkins

3) Set security options to “false” from config.xml

4) Then open localhost:8090 and see if you can see Jenkins Interface

5) Install all default plugins plus following plugins to work Jenkins correctly with Bitbucket and
dev requirements for my workflow
        a. Bitbucket pull request builder plugin
        b. Maven integration plugin
        c. MS build plugin
       d. Next build number plugin
       e. NodeJS plugin
       f. SSH Agent Plugin      
       g. SSh plugin
       h. Self-organizing swarm plugin
       i. Categorized view plugin
       j. Publish-over ssh
       k. Schedule build
       l. Nugget
       m. Vagrant

6) Install git bash in the machine

7) From git bash, generate ssh-keys , ssh-keygen

8) Add the public key(id_rsa.pub) in BitBucket under group account

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

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)
        {
           
          _listener.UnHookKeyboard();
          _listener.HookKeyboard();
        }

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

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

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 http://doc.arcgis.com/en/arcgis-online/.

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.

Source: http://discomap.eea.europa.eu/map/giseionet/Publishing_data_to_the_web_with_ArcGIS_Online.pdf

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

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);  
10:    
11:          Feature polygonFeature = layer.GetNextFeature();  
12:    
13:          long featureCountInLayer = layer.GetFeatureCount(1);  
14:          for (int i = 1; i <= featureCountInLayer; i++) {  
15:    
16:            Geometry polygonGeom = polygonFeature.GetGeometryRef();  
17:    
18:            string coordinates = "POINT (-100.726 38.995)";  
19:    
20:            SpatialReference spatialRef = layer.GetSpatialRef();  
21:            Geometry point = Ogr.CreateGeometryFromWkt(ref coordinates, spatialRef);  
22:    
23:            bool isInside = point.Within(polygonGeom);  
24:    
25:            if (isInside)  
26:            {  
27:              var val = polygonFeature.GetFieldAsString(4);  
28:              Console.WriteLine("Found one");  
29:            }  
30:    
31:            polygonFeature = layer.GetNextFeature();            
32:          }         
33:            
34:        }  
35:        catch (Exception ex)   
36:        {  
37:    
38:          Console.WriteLine(ex.Message);  
39:        }          
40:        
41:      }  

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

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);  
     }  
   

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

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):  
     fidIndices.pop(0)  
     redundantIndices = tuple(fidIndices)  
     multipleIndices = True  
       
   if(multipleIndices):  
     tempFormattedRow = [ tempFormattedRow[i] for i in xrange(len(tempFormattedRow)) if i not in set(redundantIndices) ]      
     writer.writerow(tempFormattedRow)  
   else:  
     writer.writerow(tempFormattedRow)  
 result.close()     
 [fn.close() for fn in openedFileList]  

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