Class: GDAL::GeoTransform

Inherits:
Object
  • Object
show all
Includes:
FFI::GDAL
Defined in:
lib/ffi-gdal/geo_transform.rb

Constant Summary

Constants included from FFI::GDAL

FFI::GDAL::ALTER_ALL_FLAG, FFI::GDAL::ALTER_NAME_FLAG, FFI::GDAL::ALTER_TYPE_FLAG, FFI::GDAL::ALTER_WIDTH_PRECISION_FLAG, FFI::GDAL::AppDefined, FFI::GDAL::AssertionFailed, FFI::GDAL::CPLES_BackslashQuotable, FFI::GDAL::CPLES_CSV, FFI::GDAL::CPLES_SQL, FFI::GDAL::CPLES_URL, FFI::GDAL::CPLES_XML, FFI::GDAL::CPLES_XML_BUT_QUOTES, FFI::GDAL::CPLE_WrongFormat, FFI::GDAL::CPLErr, FFI::GDAL::CPLValueType, FFI::GDAL::CPL_ENC_ASCII, FFI::GDAL::CPL_ENC_ISO8859_1, FFI::GDAL::CPL_ENC_LOCALE, FFI::GDAL::CPL_ENC_UCS2, FFI::GDAL::CPL_ENC_UCS4, FFI::GDAL::CPL_ENC_UTF16, FFI::GDAL::CPL_ENC_UTF8, FFI::GDAL::CSLT_ALLOWEMPTYTOKENS, FFI::GDAL::CSLT_HONOURSTRINGS, FFI::GDAL::CSLT_PRESERVEESCAPES, FFI::GDAL::CSLT_PRESERVEQUOTES, FFI::GDAL::CSLT_STRIPENDSPACES, FFI::GDAL::CSLT_STRIPLEADSPACES, FFI::GDAL::FileIO, FFI::GDAL::GDALAccess, FFI::GDAL::GDALAsyncStatusType, FFI::GDAL::GDALColorInterp, FFI::GDAL::GDALDataType, FFI::GDAL::GDALMD_AOP_AREA, FFI::GDAL::GDALMD_AOP_POINT, FFI::GDAL::GDALMD_AREA_OR_POINT, FFI::GDAL::GDALPaletteInterp, FFI::GDAL::GDALRATFieldType, FFI::GDAL::GDALRATFieldUsage, FFI::GDAL::GDALRWFlag, FFI::GDAL::GDALTileOrganization, FFI::GDAL::GDAL_DCAP_CREATE, FFI::GDAL::GDAL_DCAP_CREATECOPY, FFI::GDAL::GDAL_DCAP_OPEN, FFI::GDAL::GDAL_DCAP_RASTER, FFI::GDAL::GDAL_DCAP_VECTOR, FFI::GDAL::GDAL_DCAP_VIRTUALIO, FFI::GDAL::GDAL_DMD_CREATIONDATATYPES, FFI::GDAL::GDAL_DMD_CREATIONOPTIONLIST, FFI::GDAL::GDAL_DMD_EXTENSION, FFI::GDAL::GDAL_DMD_EXTENSIONS, FFI::GDAL::GDAL_DMD_HELPTOPIC, FFI::GDAL::GDAL_DMD_LONGNAME, FFI::GDAL::GDAL_DMD_MIMETYPE, FFI::GDAL::GDAL_DMD_OPTIONLIST, FFI::GDAL::GDAL_DMD_SUBDATASETS, FFI::GDAL::GDAL_DS_LAYER_CREATIONOPTIONLIST, FFI::GDAL::GDAL_OF_ALL, FFI::GDAL::GDAL_OF_RASTER, FFI::GDAL::GDAL_OF_READONLY, FFI::GDAL::GDAL_OF_SHARED, FFI::GDAL::GDAL_OF_UPDATE, FFI::GDAL::GDAL_OF_VECTOR, FFI::GDAL::GDAL_OF_VERBOSE_ERROR, FFI::GDAL::GMF_ALL_VALID, FFI::GDAL::GMF_ALPHA, FFI::GDAL::GMF_NODATA, FFI::GDAL::GMF_PER_DATASET, FFI::GDAL::IllegalArg, FFI::GDAL::NoWriteAccess, FFI::GDAL::None, FFI::GDAL::NotSupported, FFI::GDAL::ODrCCreateDataSource, FFI::GDAL::ODrCDeleteDataSource, FFI::GDAL::ODsCCreateGeomFieldAfterCreateLayer, FFI::GDAL::ODsCCreateLayer, FFI::GDAL::ODsCDeleteLayer, FFI::GDAL::OGRAxisOrientation, FFI::GDAL::OGRDatumType, FFI::GDAL::OGRERR_CORRUPT_DATA, FFI::GDAL::OGRERR_FAILURE, FFI::GDAL::OGRERR_INVALID_HANDLE, FFI::GDAL::OGRERR_NONE, FFI::GDAL::OGRERR_NOT_ENOUGH_DATA, FFI::GDAL::OGRERR_NOT_ENOUGH_MEMORY, FFI::GDAL::OGRERR_UNSUPPORTED_GEOMETRY_TYPE, FFI::GDAL::OGRERR_UNSUPPORTED_OPERATION, FFI::GDAL::OGRERR_UNSUPPORTED_SRS, FFI::GDAL::OGRFieldType, FFI::GDAL::OGRJustification, FFI::GDAL::OGRNullFID, FFI::GDAL::OGRStyleToolClassID, FFI::GDAL::OGRStyleToolParamBrushID, FFI::GDAL::OGRStyleToolParamLabelID, FFI::GDAL::OGRStyleToolParamPenID, FFI::GDAL::OGRStyleToolParamSymbolID, FFI::GDAL::OGRStyleToolUnitsID, FFI::GDAL::OGRUnsetMarker, FFI::GDAL::OGR_Z_MARKER, FFI::GDAL::OGRwkbByteOrder, FFI::GDAL::OGRwkbGeometryType, FFI::GDAL::OGRwkbVariant, FFI::GDAL::OLCAlterFieldDefn, FFI::GDAL::OLCCreateField, FFI::GDAL::OLCCreateGeomField, FFI::GDAL::OLCDeleteFeature, FFI::GDAL::OLCDeleteField, FFI::GDAL::OLCFastFeatureCount, FFI::GDAL::OLCFastGetExtent, FFI::GDAL::OLCFastSetNextByIndex, FFI::GDAL::OLCFastSpatialFilter, FFI::GDAL::OLCIgnoreFields, FFI::GDAL::OLCRandomRead, FFI::GDAL::OLCRandomeWrite, FFI::GDAL::OLCReorderFields, FFI::GDAL::OLCSequentialWrite, FFI::GDAL::OLCStringsAsUTF8, FFI::GDAL::OLCTransactions, FFI::GDAL::ObjectNull, FFI::GDAL::OpenFailed, FFI::GDAL::OutOfMemory, FFI::GDAL::UserInterrupt, FFI::GDAL::VERSION, FFI::GDAL::VSI_STAT_EXISTS_FLAG, FFI::GDAL::VSI_STAT_NATURE_FLAG, FFI::GDAL::VSI_STAT_SIZE_FLAG, FFI::GDAL::WKB_25D_BIT

Instance Attribute Summary collapse

Instance Method Summary collapse

Methods included from FFI::GDAL

#CPLFree, #cpla_assert, find_lib, #gdal_check_version, gdal_library_path, search_paths, #srcval, #validate_pointer0, #validate_pointer1, #validate_pointer_err

Constructor Details

#initialize(dataset, geo_transform_pointer: nil) ⇒ GeoTransform

Returns a new instance of GeoTransform.

Parameters:

  • gdal_dataset (FFI::Pointer) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 11

def initialize(dataset, geo_transform_pointer: nil)
  @gdal_dataset = if dataset.nil?
    FFI::MemoryPointer.new(:pointer)
  elsif dataset.is_a? GDAL::Dataset
    dataset.c_pointer
  else
    dataset
  end

  @gdal_geo_transform = if geo_transform_pointer
    geo_transform_pointer
  else
    container_pointer = FFI::MemoryPointer.new(:double, 6)
    GDALGetGeoTransform(@gdal_dataset, container_pointer).to_ruby
    container_pointer
  end

  to_a
end

Instance Attribute Details

#gdal_dataset ⇒ Object

Returns the value of attribute gdal_dataset.



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# File 'lib/ffi-gdal/geo_transform.rb', line 8

def gdal_dataset
  @gdal_dataset
end

Instance Method Details

#c_pointer ⇒ Object 



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# File 'lib/ffi-gdal/geo_transform.rb', line 31

def c_pointer
  @gdal_geo_transform
end

#null? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 35

def null?
  @gdal_geo_transform.null?
end

#pixel_height ⇒ Float

AKA Y-pixel size. In wikipedia’s World Map definition, this is “E”.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 113

def pixel_height
  return nil if null?

  @gdal_geo_transform[5].read_double
end

#pixel_width ⇒ Float

AKA X-pixel size. In wikipedia’s World Map definition, this is “A”.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 73

def pixel_width
  return nil if null?

  @gdal_geo_transform[1].read_double
end

#to_a ⇒ Array

All attributes as an Array, in the order:

* x_origin
* pixel_width
* x_rotation
* y_origin
* y_rotation
* pixel_height

Returns:

  • (Array) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 48

def to_a
  [
    x_origin,
    pixel_width,
    x_rotation,
    y_origin,
    y_rotation,
    pixel_height
  ]
end

#x_origin ⇒ Float

X-coordinate of the center of the upper left pixel. In wikipedia’s World Map definition, this is “C”.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 63

def x_origin
  return nil if null?

  @gdal_geo_transform[0].read_double
end

#x_projection(x_pixel, y_pixel) ⇒ Float

The calculated UTM easting of the pixel on the map.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 122

def x_projection(x_pixel, y_pixel)
  return nil if null?

  (pixel_width * x_pixel) + (x_rotation * y_pixel) + x_origin
end

#x_rotation ⇒ Float

Rotation about the x-axis. In wikipedia’s World Map definition, this is “B”.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 83

def x_rotation
  return nil if null?

  @gdal_geo_transform[2].read_double
end

#y_origin ⇒ Float

Y-coordinate of the center of the upper left pixel. In wikipedia’s World Map definition, this is “F”.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 93

def y_origin
  return nil if null?

  @gdal_geo_transform[3].read_double
end

#y_projection(x_pixel, y_pixel) ⇒ Float

The calculated UTM northing of the pixel on the map.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 131

def y_projection(x_pixel, y_pixel)
  return nil if null?

  (y_rotation * x_pixel) + (pixel_height * y_pixel) + y_origin
end

#y_rotation ⇒ Float

Rotation about the y-axis. In wikipedia’s World Map definition, this is “D”.

Returns:

  • (Float) 


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# File 'lib/ffi-gdal/geo_transform.rb', line 103

def y_rotation
  return nil if null?

  @gdal_geo_transform[4].read_double
end