Sample: Projecting to GoogleMercator

Projecting Coordinates

The sample below will project individual coordinates to GoogleMercator and back to geographic.

##########################################################################
# Script to project coordinates to the GoogleMaps projection and back again
# Date: 4/12/2016
# Author: Jim Graham
##########################################################################

# Setup the gateway to BlueSpray (remember that BlueSpray must be running)

from py4j.java_gateway import JavaGateway

gateway = JavaGateway(auto_field=True)

BlueSpray = gateway.jvm.com.SchoonerTurtles


# Create the projector object from the GoogleMaps projector object

TheGCS=BlueSpray.SRS.STGCS.WGS_84

TheInputSRS=BlueSpray.SRS.STSRS.NewGeographic(TheGCS)

TheOutputSRS=BlueSpray.SRS.STSRS.NewGoogleMercator()


# Project a geographic coordinate (WGS 84) to GoogleMaps
Lat=40.0
Lon=-120.0

Values=BlueSpray.SRS.STProjectorManager.Project(Lon,Lat,TheInputSRS,TheOutputSRS)


# Get the result and project it back to geographic
Easting=Values[0]
Northing=Values[1]

Values=BlueSpray.SRS.STProjectorManager.Project(Easting,Northing,TheOutputSRS,TheInputSRS)


# Print the result
Lon2=Values[0]
Lat2=Values[1]

print("Original Lat,Lon= "+format(Lat)+", "+format(Lon))

print("Projected Easting, Northing= "+format(Easting)+", "+format(Northing))

print("Back-projected Lat,Lon= "+format(Lat2)+", "+format(Lon2))

Projecting Rasters

This sample will project a raster to GoogleMercator:

##########################################################################
# Script to project rasters to the GoogleMaps projection
# Date: 4/12/2016
# Author: Jim Graham
##########################################################################

# Setup the gateway to BlueSpray (remember that BlueSpray must be running)

from py4j.java_gateway import JavaGateway

gateway = JavaGateway(auto_field=True)

BlueSpray = gateway.jvm.com.SchoonerTurtles

# Create the projector object from the GoogleMaps projector object

TheOutputSRS=BlueSpray.SRS.STSRS.NewGoogleMercator()

# Project a geographic coordinate (WGS 84) to GoogleMaps

TheRaster=BlueSpray.Raster.STRaster()

BlueSpray.File.STFileManager.LoadFromFile("C:/Temp/W100N40_4.img",TheRaster)

BlueSpray.SRS.STProjectorManager.ProjectTo(TheRaster,TheOutputSRS)

BlueSpray.File.STFileManager.SaveToFile("C:/Temp/Projected.png",TheRaster)
  

Projecting Shapefiles

The following code will project a shapefile to GoogleMercator:

##########################################################################
# Script to project shapefiles to the GoogleMaps projection
# Date: 4/12/2016
# Author: Jim Graham
##########################################################################


# Setup the gateway to BlueSpray (remember that BlueSpray must be running)

from py4j.java_gateway import JavaGateway

gateway = JavaGateway(auto_field=True)

BlueSpray = gateway.jvm.com.SchoonerTurtles


# Create the projector object from the GoogleMaps projector object

TheOutputSRS=BlueSpray.SRS.STSRS.NewGoogleMercator()


# Project a geographic coordinate (WGS 84) to GoogleMaps

TheLayer=BlueSpray.Scene.STLayerRegions()

BlueSpray.File.STFileManager.LoadFromFile("C:/Temp/ne_110m_admin_0_countries.shp",TheLayer)

BlueSpray.SRS.STProjectorManager.ProjectTo(TheLayer,TheOutputSRS)

BlueSpray.File.STFileManager.SaveToFile("C:/Temp/Projected.shp",TheLayer)