TSLStaticMapDataLayer Class Reference

Inheritance diagram for TSLStaticMapDataLayer:

Detailed Description

Specialist data layer for the display of MapLink maps generated via MapLink Studio.

The TSLStaticMapDataLayer is an alternative to the TSLMapDataLayer for use with the OpenGL drawing surface. It offers less advanced functionality than the TSLMapDataLayer, but in return gives significantly higher performance. The differences between this layer and the TSLMapDataLayer are summarised in the limitations section.

Map data is read-only and modification of this layer by the user is limited to changing the rendering of the entities within it.

The following capabilities are available through the TSLStaticMapDataLayer component:

• Loading data
• Cache management
• Rendering
• Miscellaneous

The methods 'loadData' and 'removeData' (inherited from TSLDataLayer) allow complete maps to be loaded into and removed from the map layer.

Cache management is an important area for the map layer since it is not normally possible to hold a complete map in memory. The cache functions allows the user to fine tune the performance of a map layer by setting aside memory to hold recently accessed areas of the map so that they do not need to be loaded from disk when requested. The following cache properties are available:

• drawCacheSize which determines how much memory to use for the draw cache
• queryCacheSize, which determines how much memory to use when querying geometry from the layer
• clearDrawCache, which will clear all drawing data from memory.
• clearQueryCache, which will clear all queried geometry from memory.

Instances of this class should be destroyed using the destroy method.

Reprojection

This layer does not support runtime reprojection. It does however support realtime reprojection in conjunction with the TSLOpenGLSurface.

See also

TSLOpenGLSurface

realtime_reprojection_details

Limitations

The following functionality offered by the TSLMapDataLayer is not available on this layer. Applications requiring these features should use the TSLMapataLayer instead:

• Runtime projection is not available on the TSLStaticMapDataLayer.
• Flashback is not available on the TSLStaticMapDataLayer.
• A persistent tile cache is not available on the TSLStaticMapDataLayer.
• Dynamic renderers associated with the data layer through the drawing will not be used.

Modifying the rendering of items in the data layer, e.g. by calling load Rendering or by modifying feature rendering on the layer may cause the layer to reload data from disk.

Range-based decluttering set on the layer through TSLDrawingSurface::setDeclutterRange is only evaluated for a tile the first time that tile is drawn, so features decluttered in this fashion will remain decluttered if they are decluttered the first time the tile that contains them is drawn regardless of subsequent changes to the view resolution.

This layer can not be shared between multiple TSLOpenGLSurface instances.

Public Member Functions
	TSLStaticMapDataLayer ()
void	drawCacheSize (unsigned int size)
unsigned int	drawCacheSize () const
void	clearDrawCache ()
void	clearQueryCache ()
bool	clearRuntimeProjection ()
TSLEntity *	findEntityID (TSLEntityID entityID, TSLSLMEntityRefHandler *handler)
TSLStyleID	getBackgroundColour () const
bool	getDetailLayerMUExtent (const char *layerName, double *x1, double *y1, double *x2, double *y2) const
const char *	getDetailLayerName (int nth) const
bool	getDetailLayerTMCExtent (const char *layerName, TSLTMC *x1, TSLTMC *y1, TSLTMC *x2, TSLTMC *y2) const
bool	getLayerLoadingThreshold (const char *layerName, double *upperThreshold, double *lowerThreshold) const
bool	getMUExtent (double *x1, double *y1, double *x2, double *y2) const
int	getNumDetailLayers () const
const char *	getOverviewLayer () const
bool	getPaletteFilename (TSLSimpleString &filename) const
bool	getPathlistFilename (TSLSimpleString &filename) const
bool	getSynchronousLoading () const
int	metadata (int pos, char **fileName)
void	metadata (int sourceID, TSLSimpleString &filename) const
int	metadataCount () const
bool	MUToTMC (double x1, double y1, TSLTMC *x2, TSLTMC *y2) const
void	queryCacheSize (unsigned int size)
int	queryCacheSize () const
const TSLCoordinateSystem *	queryCoordinateSystem () const
const TSLCoordinateSystem *	queryMapCoordinateSystem () const
TSLCoordinateSystem *	queryRuntimeCoordinateSystem () const
bool	removeLayer (const char *layerName)
bool	setLayerLoadingThreshold (const char *layerName, double upperThreshold, double lowerThreshold=0.0)
void	setSynchronousLoading (bool synchronous)
bool	setRuntimeProjection (const TSLCoordinateSystem *projection, double greatCircleDistance, TSLRuntimeProjectionChangedCallback callback, void *arg)
bool	setRuntimeProjectionOrigin (double latitude, double longitude, TSLRuntimeProjectionChangedCallback callback, void *arg)
double	TMCperMU () const
bool	TMCToMU (TSLTMC x1, TSLTMC y1, double *x2, double *y2) const
void *	operator new (size_t size) TSL_NO_THROW
void *	operator new (size_t size, char *filename, int line)
Public Member Functions inherited from TSLDataLayer
void	addDrawingCallback (TSLDataLayerDrawingCallback *drawingCallback)
bool	addFeatureRendering (const char *featureName, TSLFeatureID featureID)
bool	addLoader (TSLFileLoader *loader, TSLLoaderAppCallback callback, void *arg, TSLAllLoadedCallback allLoadedCallback=0, void *arg2=0)
bool	addPathList (const TSLPathList *path_list)
void	cancelFlashback ()
bool	clearFeatureRendering (const char *featureName, TSLFeatureID featureID)
TSLDataHandler *	createDataHandler (const char *config_file=0)
TSLHistoryVersion	currentVersion () const
TSLDataHandler *	dataHandler ()
const TSLDataHandler *	dataHandler () const
void	destroy ()
bool	entityIsVisible (const TSLEntity *entity, const TSLDrawingSurface *drawingSurface) const
const TSLFeatureClassList *	featureList () const
const TSLFeatureClassList *	featureList (const char *detailLayerName) const
bool	fileModificationTime (const char *filename, TSLTimeType &lastModificationTime)
TSLEntity *	findEntity (TSLTMC x, TSLTMC y, TSLTMC aperture, int depth, const char *featureName=0, int drawingSurfaceID=-1)
bool	findFile (const char *filename, TSLSimpleString &foundPath) const
void	flashbackToTimestamp (TSLHistoryTimestamp timestamp, TSLLayerArchiveCallback archiveCallback, void *arg=0)
void	flashbackToTimestamp (TSLHistoryTimestamp timestamp, TSLLayerArchiveTileCallback archiveTileCallback, void *arg=0)
void	flashbackToVersion (TSLHistoryVersion version, TSLLayerArchiveCallback archiveCallback, void *arg=0)
void	flashbackToVersion (TSLHistoryVersion version, TSLLayerArchiveTileCallback archiveTileCallback, void *arg=0)
bool	getActiveLayerName (const TSLEnvelope &extent, double screenResolution, TSLSimpleString &activeLayerName) const
TSLEntityIterator *	getEntityIterator (const char *detailLayer, TSLSelector *selector=NULL, TSLEnvelope *extent=NULL, bool splitOptimisedPrimitives=true)
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeInt attribute, int *result) const
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeDouble attribute, double *result) const
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeBool attribute, bool *result) const
bool	getFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributes *result) const
TSLFileLoader *	getLoader ()
bool	getMUExtent (double *x1, double *y1, double *x2, double *y2, int drawingSurfaceID=-1) const
bool	getTMCExtent (TSLTMC *x1, TSLTMC *y1, TSLTMC *x2, TSLTMC *y2, int drawingSurfaceID=-1) const
bool	getUUExtent (double *x1, double *y1, double *x2, double *y2, const TSLDrawingSurface *drawingSurface) const
bool	importHistory (TSLHistoryVersion mapVersion, TSLHistoryTimestamp timestamp, TSLHistoryImportSet *historySet)
bool	latLongToTMC (double latitude, double longitude, TSLTMC *x, TSLTMC *y, bool local=false) const
bool	latLongToTMC (int num, double *latitudes, double *longitudes, TSLTMC *xs, TSLTMC *ys, bool local=false) const
TSLDataLayerTypeEnum	layerType () const
bool	loadData (const char *filename)
bool	loadRendering (const char *filename)
void	notifyChanged (bool changed=true)
TSLMapQuery *	query (TSLTMC x1, TSLTMC y1, TSLTMC x2, TSLTMC y2, int depth=-1, const char *featureName=NULL, int drawingSurfaceID=-1) const
TSLMapQuery *	query (TSLTMC x1, TSLTMC y1, TSLTMC x2, TSLTMC y2, TSLSelector *selector, int drawingSurfaceID=-1) const
const TSLCoordinateSystem *	getCoordinateSystem () const
bool	queryVersionHistory (const TSLEnvelope &extent, TSLVersionHistorySet &history)
void	refreshFlashback ()
bool	removeData ()
void	releaseResources (int surfaceID)
bool	saveRendering (const char *filename, TSLMapLinkVersion ver=TSL_CURRENT_MAPLINK_VERSION)
bool	setCoordinateSystem (const TSLCoordinateSystem *coordinateSystem)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeInt attribute, int value)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeDouble attribute, double value)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributeBool attribute, bool value)
bool	setFeatureRendering (const char *featureName, TSLFeatureID featureID, TSLRenderingAttributes *value)
bool	TMCToLatLong (TSLTMC x, TSLTMC y, double *latitude, double *longitude, bool local=false, bool boundCheck=true) const
bool	TMCToLatLong (int num, TSLTMC *xs, TSLTMC *ys, double *latitudes, double *longitudes, bool local=false) const
const TSLVersionHistorySet *	versionHistory () const

Constructor & Destructor Documentation

TSLStaticMapDataLayer()

TSLStaticMapDataLayer::TSLStaticMapDataLayer

(

)

Member Function Documentation

clearDrawCache()

void TSLStaticMapDataLayer::clearDrawCache

(

)

Clears the tile cache used for drawing for this data layer.

This method requests the data layer to clear all cached data from memory. After a call to this method any draw operation involving the layer will re-load all required map data from its original location.

clearQueryCache()

void TSLStaticMapDataLayer::clearQueryCache

(

)

Clears the tile cache used for querying for this data layer.

This method requests the data layer to clear all cached data from memory. After a call to this method any query operation involving the layer will re-load all required map data from its original location.

clearRuntimeProjection()

bool TSLStaticMapDataLayer::clearRuntimeProjection

(

)

Clears any runtime projection set with 'setRuntimeProjection'.

Returns true on success, false otherwise.

drawCacheSize() [1/2]

unsigned int TSLStaticMapDataLayer::drawCacheSize

(

)

const

Query the amount of memory that the drawing cache may currently use, in kilobytes.

drawCacheSize() [2/2]

void TSLStaticMapDataLayer::drawCacheSize

(

unsigned int

size

)

Sets maximum size of the tile cache used for drawing.

This method allows the user to set the amount of memory that the tile cache can use. To operate more efficiently the data layer holds data in memory so that it does not need to reload data from disk every time a draw request is made. The larger the cache size, the more data can be held in memory and draw requests are handled much more efficiently. However the client application must find a compromise between a large cache size and the memory requirements of the application itself.

The default tile cache is 32Mb (32768 KB)

Parameters

size	Size of the cache in kilobytes.

findEntityID()

TSLEntity * TSLStaticMapDataLayer::findEntityID	(	TSLEntityID	entityID,
		TSLSLMEntityRefHandler *	handler )

Find an entity in a seamless layer, given its ID.

This method returns a pointer to the first visible, selectable entity matching the given ID, If the map does not contain a seamless layer or if no such entity exists in the seamless layer, NULL is returned.

Entities are marked as visible or selectable via TSLRenderingAttributeVisible and TSLRenderingAttributeSelectable.

Parameters

entityID	the entity ID
handler	the entity reference handler

The entity reference handler must be configured appropriately otherwise this method will return NULL; in particular, if the handler has no associated seamless configuration object, then NULL will be returned.

getBackgroundColour()

TSLStyleID TSLStaticMapDataLayer::getBackgroundColour

(

)

const

This method returns the background colour index for the loaded map.

Returns the background colour index of the map or -1 if the colour is not defined. The return value will either be a colour index or a composed RGB value. See tslcolourhelper.h for information on determining the type and in the case of an RGB value uncomposing it back into its respective components.

getDetailLayerMUExtent()

bool TSLStaticMapDataLayer::getDetailLayerMUExtent	(	const char *	layerName,
		double *	x1,
		double *	y1,
		double *	x2,
		double *	y2 ) const

Query extent of detail layer.

This method allows the user to get the extent of a particular detail layer of the map. The extent returned is in Map Unit co-ordinates.

Parameters

layerName	Layer for which the extent are returned
(x1,y1)	Storage for bottom left corner
(x2,y2)	Storage for top right corner

Returns

true on success, false otherwise.

getDetailLayerName()

const char * TSLStaticMapDataLayer::getDetailLayerName

(

int

nth

)

const

This method returns name of the 'nth' detail layer.

The name is stored in an internal buffer which may be overwritten by subsequent calls to this method.

Returns a pointer to the name of the 'nth'detail layer, NULL if no detail layers are loaded.

getDetailLayerTMCExtent()

bool TSLStaticMapDataLayer::getDetailLayerTMCExtent	(	const char *	layerName,
		TSLTMC *	x1,
		TSLTMC *	y1,
		TSLTMC *	x2,
		TSLTMC *	y2 ) const

Query extent of detail layer.

This method allows the user to get the extent of a particular detail layer of the map. The extent returned is in internal TMC co-ordinates.

Parameters

layerName	Layer for which the extent are returned
(x1,y1)	Storage for bottom left corner
(x2,y2)	Storage for top right corner

Returns

true on success, false otherwise.

getLayerLoadingThreshold()

bool TSLStaticMapDataLayer::getLayerLoadingThreshold	(	const char *	layerName,
		double *	upperThreshold,
		double *	lowerThreshold ) const

Allows the top and bottom thresholds for which a particular layer is displayed to be queried at runtime.

Parameters

layerName	The name of the layer to query.
lowerThreshold	The lower value in Map Units per Pixel.
upperThreshold	The upper value in Map Units per Pixel.

Return true on success, false otherwise.

getMUExtent()

bool TSLStaticMapDataLayer::getMUExtent	(	double *	x1,
		double *	y1,
		double *	x2,
		double *	y2 ) const

Query extent of map, in map units.

This method requests the full extent of the area covered by the TSLData Layer. The returned values will be in map unit.

Parameters

(x1,y1)	Storage for bottom left co-ordinate of the extent.
(x2,y2)	Storage for top right co-ordinate of the extent.

Returns

true if successful, false if no data is loaded.

getNumDetailLayers()

int TSLStaticMapDataLayer::getNumDetailLayers

(

)

const

This method returns the number of detail layers in the currently loaded map.

Returns number of detail layers in the currently loaded map. 0 if no map is loaded

getOverviewLayer()

const char * TSLStaticMapDataLayer::getOverviewLayer

(

)

const

This method returns name of a layer to be used for an overview.

At present, this method will return "thumbnail" or "overview" if those detail layers exist. Otherwise it returns that detail layer with the largest extent. In a future release, it may be possible to tag a detail layer to be used via MapLink Studio.

Returns a pointer to the name of the overview detail layer, NULL if no detail layers are loaded.

getPaletteFilename()

bool TSLStaticMapDataLayer::getPaletteFilename

(

TSLSimpleString &

filename

)

const

This method queries the full path to the palette file associated with this map data layer if one exists.

Parameters

filename

This will be populated with the palette filename should one be associated

Return true if the filename parameter was populated with the paletted filename, false otherwise.

getPathlistFilename()

bool TSLStaticMapDataLayer::getPathlistFilename

(

TSLSimpleString &

filename

)

const

This method queries the full path to the pathlist definition file associated with this map data layer if one exists.

Parameters

filename

This will be populated with the pathlist definition file path should one be associated

Return true if the filename parameter was populated with the pathlist filename, false otherwise.

getSynchronousLoading()

bool TSLStaticMapDataLayer::getSynchronousLoading

(

)

const

Queries whether the layer is currently set to synchronous loading of its data. Synchronous loading is usually only required when printing as all data that is to be drawn must be loaded before the print draw occurs. Use the set SynchronousLoading method to alter the value of this setting.

metadata() [1/2]

int TSLStaticMapDataLayer::metadata	(	int	pos,
		char **	fileName )

This method returns the source ID and the full path of the associated xml file for the given position.

Parameters

pos	the nth piece of metadata for which source ID and the xml file are required
fileName	the filename of the associated metadata (memory owned by the caller)

metadata() [2/2]

void TSLStaticMapDataLayer::metadata	(	int	sourceID,
		TSLSimpleString &	filename ) const

The method returns the full path of the Envitia generated metadata xml file associated with the given source ID in the filename argument.

Parameters

sourceID	sourceID for which associated metadata xml file path should be returned
filename	The full path to the metadata file. An empty path is returned if there was no metadata file.

metadataCount()

int TSLStaticMapDataLayer::metadataCount

(

)

const

This method returns a count of the number of metadata files associated with this layer.

MUToTMC()

bool TSLStaticMapDataLayer::MUToTMC	(	double	x1,
		double	y1,
		TSLTMC *	x2,
		TSLTMC *	y2 ) const

Map unit to TMC conversion method.

Parameters

x1	input X (map units).
y1	input Y (map units).
x2	output X (TMC units).
y2	output Y (TMC units).

Return true on success, false otherwise.

operator new() [1/2]

void * TSLStaticMapDataLayer::operator new

(

size_t

size

)

Overridden allocation to redirect to MapLink

operator new() [2/2]

void * TSLStaticMapDataLayer::operator new	(	size_t	size,
		char *	filename,
		int	line )

When included in an MFC application in debug mode, the debug new expects this to be here. Override it and return the same as the normal one. The library must include it when compiled in release mode, since the user's application may be in debug mode.

queryCacheSize() [1/2]

int TSLStaticMapDataLayer::queryCacheSize

(

)

const

Returns the amount of memory that the query cache may currently use, in kilobytes.

queryCacheSize() [2/2]

void TSLStaticMapDataLayer::queryCacheSize

(

unsigned int

size

)

Set maximum size of the tile cache used for data layer queries (e.g. find Entity).

This method allows the user to set the amount of memory that the tile cache can use. To operate more efficiently the data layer holds data in memory so that it does not need to reload data from disk every time a query is performed. The larger the cache size the more data can be held in memory. However the client application must find a compromise between a large cache size and the memory requirements of the application itself.

The default tile cache is 16Mb (16384 KB)

Parameters

size	Size of the cache in kilobytes.

queryCoordinateSystem()

const TSLCoordinateSystem * TSLStaticMapDataLayer::queryCoordinateSystem

(

)

const

Query for the coordinate system used by this layer to convert between map units and lat/long.

This method requests the TSLMapDataLayer to return a TSLCoordinateSystem object which allows the user to access information concerning the transforms used to create the map. The TSLCoordinateSystem is only valid as long as no new map has been loaded into the layer since last obtaining the component.

If runtime projection is in use, this will be the same object as returned from queryRuntimeCoordinateSystem(). If runtime projection is not in use, this will be the same object as returned from queryMapCoordinateSystem().

queryMapCoordinateSystem()

const TSLCoordinateSystem * TSLStaticMapDataLayer::queryMapCoordinateSystem

(

)

const

Query for the coordinate system associated with the map that is loaded in this layer.

This method requests the TSLStaticMapDataLayer to return a TSLCoordinateSystem object which allows the user to access information concerning the transforms used to create the map. The TSLCoordinateSystem is only valid as long as no new map has been loaded into the layer since last obtaining the component.

If realtime projection is not in use, this will be the same object as returned from queryCoordinateSystem(). If realtime projection is in use, queryRuntimeCoordinateSystem() will return the transform given to setRuntimeProjection() and this method will return the transform associated with the loaded map.

queryRuntimeCoordinateSystem()

TSLCoordinateSystem * TSLStaticMapDataLayer::queryRuntimeCoordinateSystem

(

)

const

Query for the runtime coordinate system added with setRuntimeProjection.

If realtime projection is not in use, this will return NULL.

removeLayer()

bool TSLStaticMapDataLayer::removeLayer

(

const char *

layerName

)

Remove existing detail layer.

This method requests the TSLMapDataLayer to remove the named detail layer. If the layer identified by input layer file name does not exist in the TSLMap DataLayer then this will have no effect. If the layer is currently on the display then nothing will happen until the data is redisplayed.

Parameters

layerName

The name of the layer to be removed.

Returns

true if the layer is removed, false otherwise.

setLayerLoadingThreshold()

bool TSLStaticMapDataLayer::setLayerLoadingThreshold	(	const char *	layerName,
		double	upperThreshold,
		double	lowerThreshold = 0.0 )

Allows the top and bottom thresholds for which a particular layer is displayed to be set at runtime, rather than relying on settings via MapLink studio.

Parameters

layerName	The name of the layer to apply the changes.
upperThreshold	The upper threshold in Map Units per pixel.
lowerThreshold	The lower threshold in Map Units per pixel. Defaulted to 0.0.

Return true on success, false otherwise.

setRuntimeProjection()

bool TSLStaticMapDataLayer::setRuntimeProjection	(	const TSLCoordinateSystem *	projection,
		double	greatCircleDistance,
		TSLRuntimeProjectionChangedCallback	callback,
		void *	arg )

Changes the current projection if using runtime projection.

If a callback is given, then the recalculation of the projection will happen in a background thread, and the callback will be called when it is complete. Drawing operations will fail if called during the time when the recalculation is being performed.

If the callback parameter is null then the calculations happen synchronously in the main thread, within this call.

The same callback pointer may be given to both setRuntimeProjection and set RuntimeProjectionOrigin. The reason parameter of the callback indicates the reason for the callback.

If the runtime projection is referenced against a different datum to that against which the map was created, then a suitable datum transform must be set on the projection before calling this method.

Note

The TMCperMU value for the specified coordinate system is currently ignored when the coordinate system is used for run-time projection. Under those circumstances the TMCperMU is calculated according to the input data extent.

Parameters

projection	the new coordinate system to use. This is copied, the pointer is not stored.
greatCircleDistance	a map tile will be projected if any part of the tile falls within this distance from the projection origin (metres). Set this value to the maximum geographical area the you need to view. Reducing the value makes setprojection and setProjectionOrigin work faster. Avoid values so large that the edge of the map projection becomes visible.
callback	callback to call when new projection calculated, or NULL if calculations to be synchronous
arg	user-defined argument, returned in callback.

Returns

true on success, false on failure.

setRuntimeProjectionOrigin()

bool TSLStaticMapDataLayer::setRuntimeProjectionOrigin	(	double	latitude,
		double	longitude,
		TSLRuntimeProjectionChangedCallback	callback,
		void *	arg )

Changes the origin of the current projection if using runtime projection.

If a callback is given, then the recalculation of the projection will happen in a background thread, and the callback will be called when it is complete. Drawing operations will fail if called during the time when the recalculation is being performed.

If the callback parameter is null then the calculations happen synchronously in the main thread, within this call.

The same callback pointer may be given to both setRuntimeProjection and setRuntimeProjectionOrigin. The reason parameter of the callback indicates the reason for the callback.

Parameters

(latitude,longitude)	the new projection origin to be set, degrees
callback	callback to call when new projection calculated, or null if calculations to be synchronous
arg	user-defined argument, returned in callback.

Returns

true on success, false on failure.

setSynchronousLoading()

void TSLStaticMapDataLayer::setSynchronousLoading

(

bool

synchronous

)

Call with the synchronous parameter set to true to load map data synchronously, it also inhibits callbacks after each map tile is loaded.

Call this during printing to ensure that all map data is loaded synchronously, as printing may use a different tile resolution from those displayed on the screen.

The allLoadedCallback callback (as passed in the addLoader() method) is always called at the end of loading all tiles, but the tile loaded callback (as passed in the addLoader() method) is only called for asynchronous loading.

TMCperMU()

double TSLStaticMapDataLayer::TMCperMU

(

)

const

This method returns the number of TMCs per Map Unit for the loaded map.

Returns the number of TMCs per Map Unit if data is loaded, 0.0 if not.

TMCToMU()

bool TSLStaticMapDataLayer::TMCToMU	(	TSLTMC	x1,
		TSLTMC	y1,
		double *	x2,
		double *	y2 ) const

TMC to map unit conversion method.

Parameters

x1	input X (TMC units).
y1	input Y (TMC units).
x2	output X (map units).
y2	output Y (map units).

Return true on success, false otherwise.