CodeSnippets: KML_Driver_examples.pl

#!/usr/bin/perl
##
##      KML Driver Test, using Perl and OGR
##  written for GDAL/OGR v1.5
##
##      09Dec07  -bh
##

## -- If you want to use development libraries, add the path here
#use lib '/Users/Shared/srcs/gdal_trunk/swig/perl/blib/lib';
#use lib '/Users/Shared/srcs/gdal_trunk/swig/perl/blib/arch';
use Geo::Ogr;

##==========================================================
## main program

my $dstFilename = 'tmp/tKML' . rand(100) . '.kml';

my $driver = Geo::OGR::GetDriverByName( 'KML' )
        or die( "Cant open driver KML $! $@" );
my $datasource = $driver->CreateDataSource( "/Users/Shared/srcs/ogrTutorial/$dstFilename" ) 
        or die( "Cant open file $! $@" );

##---------------------------
## Now, make a few new layers
        newGeom_Point();
        newGeom_Polygon();
        newGeom_Point25D();
        newGeom_LineString();
        newGeom_Unknown();


exit(0);

##==========================================================
##-- Supported Layer Types --
        #Point
        #Polygon
        #LineString
        #Unknown
        
## -- Unsupported Layer Types --
        #MultiPoint             MultiPolygon            MultiLineString
        #Point25D               Polygon25D                      LineString25D
        #MultiPoint25D  MultiPolygon25D         MultiLineString25D
        
##==========================================================
sub newGeom_Point {
        my ($tPt, $tStr, $type, $feature); 

        ## Create a Layer.. 
        ##  the first param shows up as the Folder Name in KML
        $type = 'Point';
        my $layer = $datasource->CreateLayer( ($type . '_layer'), undef, $type );
        $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        #my $dRef = $feature->GetDefnRef();
        #print $dRef->GetGeomType();

        ##---------------------------------------------------------
        ## SetField(0,x) will set the KML Name of this feature
        $feature->SetField( 'Name', "Remarkably Remote Rest Stop" );    
        ## SetField(1,x) will set the KML Description of this feature
        ## the description will generally accept minimal HTML, 
        ##  if escaped with CDATA. XML special chars will be escaped for you
        ##  but this seems buggy right now.. see below for another example
        $feature->SetField( 'Description', "top doggy" );
        # this had problems for me
        #$feature->SetField( 1, "top <doggy>" );        
        
        ## now create a new geometry from WKT
        $tStr = 'POINT(' . (rand() - 122.0) . ' ' . (rand() + 35.0) . ')';
        $tPt = Geo::OGR::CreateGeometryFromWkt( $tStr );
        #print $tPt->ExportToWkt( );

        # associate the geometry with the Feature
        $feature->SetGeometry( $tPt );
        # add the feature to the layer
        $layer->CreateFeature( $feature);
        #write to disk
        $layer->SyncToDisk;
        
        # done with this Feature now
        $feature->DESTROY();
        
        ##---------------------------------------------------------
        # Make another feature
        $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        $feature->SetField( 'Name', "Purposefull Point" );      
        $feature->SetField( 'Description', "how can this be a useful description?" );   
        
        my $tPt2 =  Geo::OGR::Geometry->new( $Geo::OGR::wkbPoint );
        # Make a new Geometry as an object, then AddPoint()
        $tPt2->AddPoint( rand() - 122.0, rand() + 35.0  );
        #write it to the Layer
        writeGeom( $tPt2, $feature, $layer );

        # Now use the same feature, but make a new geometry via create()
        my $tPt3 =  Geo::OGR::Geometry->create( $type );
        # AddPoint again
        $tPt3->AddPoint( rand() - 122.0, rand() + 35.0  );
        #write it to the layer, notice the Name and Decription are repeated
        writeGeom( $tPt3, $feature, $layer );
        
        # done with this Feature now
        $feature->DESTROY();
        
        ##---------------------------------------------------------
        # Last feature
        $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        $feature->SetField( 'Name', "Google Summer of Coder" ); 

        # a try at complicated HTML content.. needs work
my $descStr = <<END0;
<![CDATA[<b>Name:</b> <i>Erik Pukinskis</i><br />
      <b>Description:</b> <i>Working on... &lt;br /&gt; 
      &lt;i&gt;<a href=http://code.google.com/soc/abisource/about.html>abi</a><br />]]>
END0
        $feature->SetField( 'Description', $descStr );  
        
        my $tPt2 =  Geo::OGR::Geometry->new( $Geo::OGR::wkbPoint );
        # Make a new Geometry as an object, then AddPoint()
        $tPt2->AddPoint( -117.1610543131828, 32.74625975767101  );
        #write it to the Layer
        writeGeom( $tPt2, $feature, $layer );
        
        # Perl interfaces will auto-dispose any object with local scope
        return;

        ## other confusing stuff from the Perl interfaces
        #my $tFtrDef = new Geo::OGR::FeatureDefn( "Homer" );
        #$tFtrDef->Schema(
        #       Fields=>[Geo::OGR::FieldDefn->create( Name=>'OneName',Description=>'desc')]);
        # not at all the right call next
        #$tFtrDef->AddFieldDefn( "Name", "fred" );
}

##-------------------------------------------------------------------------
## newGeom_Point25D -  make a 25D point in a POINT layer.. 
##  write out to KML and notice the 25D point is intact. 
##  KML doesnt care about mixing 25D and others.. Other OGR drivers might.
##  NOTE: still finding out new ways to manipulate Geometry, so 
##  suggestions are welcome.. 

sub newGeom_Point25D {
        my ($tPt, $tStr, $type); 

        $type = 'Point';
        my $layer = $datasource->CreateLayer( ($type . '_layer'), undef, $type );
        my $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        
        #my $dRef = $feature->GetDefnRef();
        #print $dRef->GetGeomType();
        
        ## This works, 25D with WKT
        $tStr = 'POINT(' . (rand() - 122.0) . ' ' . (rand() + 35.0) . ' ' . 155 . ')';
        $tPt = Geo::OGR::CreateGeometryFromWkt( $tStr );
        #print $tPt->ExportToWkt( );
        writeGeom( $tPt, $feature, $layer );

        # another Geometry object
        my $tPt2 =  Geo::OGR::Geometry->new( $Geo::OGR::wkbPoint );
        $tPt2->AddPoint( rand() - 122.0, rand() + 35.0 );
        ##  AddPoint() doesnt like 25D, fails.. 
        #$tPt2->AddPoint( rand() - 120.0, rand() + 35.0, 155 );
        writeGeom( $tPt2, $feature, $layer );

        my $tPt3 =  Geo::OGR::Geometry->create( $type );
        $tPt3->AddPoint( rand() - 122.0, rand() + 35.0 );
        ##  AddPoint() doesnt like 25D, fails.. 
        #$tPt3->AddPoint( rand() - 110.0, rand() + 35.0, 155  );
        writeGeom( $tPt3, $feature, $layer );
        
        return;
}

##----------------------
sub newGeom_Unknown {
        my ($tPt, $tStr, $type); 

        $type = 'Unknown';
        my $layer = $datasource->CreateLayer( ($type . '_layer'), undef, $type );
        if ( $@ ) { print $@; }
        my $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        if ( $@ ) { print $@; }

        ## try adding a LineString
        my $limit = int(rand(3)) + 1;
        my ($tNewPtX,$tNewPtY);
        $tNewPtX = (rand() - 118.0);
        $tNewPtY = (rand() + 32.0);
        $tStr = 'LINESTRING(' . $tNewPtX . ' ' . $tNewPtY . ', ';
        for ( 0..$limit ) {
                $tStr .=  ($tNewPtX + rand()) . ' ' . ($tNewPtY + rand()) . ',';
        }
        chop $tStr;
        $tStr .= ')';
        $tPt = Geo::OGR::CreateGeometryFromWkt( $tStr );
        #print $tPt->ExportToWkt( );
        writeGeom( $tPt, $feature, $layer );
        
        $feature->DESTROY();

        ## and now a Point
        $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );

        # Set the Name and Description fields
        $feature->SetField( 'Name', "All Mixed Content Point" );        
        $feature->SetField( 'Description', "draw it as I see it" );     
        
        my $tPt2 =  Geo::OGR::Geometry->new( $Geo::OGR::wkbPoint );
        # Make a new Geometry as an object, then AddPoint()
        $tPt2->AddPoint( -118.00, 32.78  );
        #write it to the Layer
        writeGeom( $tPt2, $feature, $layer );
        
        return;
}
        
##----------------------
sub newGeom_LineString {
        my ($tPt, $tStr, $type); 

        $type = 'LineString';
        my $layer = $datasource->CreateLayer( ($type . '_layer'), undef, $type );
        if ( $@ ) { print $@; }
        my $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        if ( $@ ) { print $@; }
        
        #my $dRef = $feature->GetDefnRef();
        #print $dRef->GetGeomType();
        
        ## make the feature comments now
        $feature->SetField( 'Name', "Long path to nowhere" );
        ## xml escape chars translate correctly in the display
        $feature->SetField( 'Description', "If the &lt;tessellate&gt; tag has a value of 0, the line follows a simple straight-line path from point to point" );        

        my $limit = int(rand(10)) + 1;
        my ($tNewPtX,$tNewPtY);
        $tNewPtX = (rand() - 122.0);
        $tNewPtY = (rand() + 35.0);
        $tStr = 'LINESTRING(' . $tNewPtX . ' ' . $tNewPtY . ', ';
        for ( 0..$limit ) {
                $tStr .=  ($tNewPtX + rand()) . ' ' . ($tNewPtY + rand()) . ',';
        }
        chop $tStr;
        $tStr .= ')';
        $tPt = Geo::OGR::CreateGeometryFromWkt( $tStr );
        #print $tPt->ExportToWkt( );
        writeGeom( $tPt, $feature, $layer );
        
        return;
}

##--------------------------------------------------------------------------
## newGeom_Polygon - make a Polygon Layer and sample geometry
## TODO: figure out how to set the LineStyle and PolyStyle on the Polygon
sub newGeom_Polygon {
        my ($tPt, $tStr, $type); 

        $type = 'Polygon';
        my $layer = $datasource->CreateLayer( ($type . '_layer'), undef, $type );
        my $feature = new Geo::OGR::Feature( $layer->GetLayerDefn() );
        
        #my $dRef = $feature->GetDefnRef();
        #print $dRef->GetGeomType();
        
        $tStr = 'POLYGON((';
        my $tOrigLat = (rand(2) + 35.0);
        my $tOrigLon = (rand(2) - 122.0);
        $tStr .= $tOrigLon . ' ' . $tOrigLat . ', ';
        for (1..3) {
                $tStr .= (rand(2) - 122.0) . ' ' . (rand(2) + 35.0) . ',';
        }
        $tStr .= $tOrigLon . ' ' . $tOrigLat . ' ';
        $tStr .= '))';
        $tPt = Geo::OGR::CreateGeometryFromWkt( $tStr );
        #print $tPt->ExportToWkt( );
        writeGeom( $tPt, $feature, $layer );
}

##=========================================================================
## some misc support subs

sub writeGeom {
        my ($geom,$feature,$layer) = @_;
        
        $feature->SetGeometry( $geom );
        $layer->CreateFeature( $feature);
        $layer->SyncToDisk;
}

##-------------
sub printAllTypes {
        my @types = Geo::OGR::GeometryType();
        
        my @tmp = @types;
        @types = ();
        # filter out a few of the types
        for (@tmp) {
                #next if /25/;
                next if /Ring/;
                next if /None/;
                push @types, $_;
        }
        print @types;
        exit(0);
}