diff --git a/src/GeoView-Examples/GeoViewExamples.class.st b/src/GeoView-Examples/GeoViewExamples.class.st
index d6a9284..4eb410b 100644
--- a/src/GeoView-Examples/GeoViewExamples.class.st
+++ b/src/GeoView-Examples/GeoViewExamples.class.st
@@ -346,19 +346,18 @@ GeoViewExamples class >> exampleGeoSegmentsProjected [
 { #category : #'examples - tiles provider' }
 GeoViewExamples class >> exampleGeoViewWithCartoTilesLayerUsingGoogleHybrid [
 	"This example show a map layer (assuming an internet connection to default url of google"
-	
+
 	| element layer |
 	element := GeoViewAeElement new.
-	
-	element maxScaleInMeters: element maxScaleInMeters * 8.
-	
+
+	element maxScaleInMeters: element maxScale * 8.
+
 	"add carto layer"
 	layer := GeoViewMapTilesLayer newWithGoogle name: 'Tiles Layer'.
 	layer tilesProvider beHybridType.
 	element addLayer: layer.
 
 	^ self openViewInWindow: element
-	
 ]
 
 { #category : #'examples - tiles provider' }
@@ -505,29 +504,37 @@ GeoViewExamples class >> exampleGeoViewWithCartoTilesLayerUsingOSMWithSmallTileS
 { #category : #examples }
 GeoViewExamples class >> exampleGeoViewWithCartoTilesLayerWithUpdateCenter [
 	"This example show a map layer with update of map center every seconds (during 30s)"
-	
-	| element layer newCenter space circle|
+
+	| element layer newCenter space circle |
 	element := GeoViewUtils createGeoViewForGeoObjects.
-	
-	element maxScaleInMeters: element maxScaleInMeters * 8.
-	element scaleInMeters: 150000.
-	
+
+	element maxScaleInMeters: element maxScale * 8.
+	element scale: 150000.
+
 	"add carto layer"
 	element addLayerAtFirst: GeoViewMapTilesLayer new.
-	
-	circle := GeoCircle new key: 1; radiusInMeters: 2000; fillStyle: (Color red asSmockStrokeStyle); absoluteCoordinates: AbsoluteCoordinates frBrest.
+
+	circle := GeoCircle new
+		          key: 1;
+		          radiusInMeters: 2000;
+		          fillStyle: Color red asSmockStrokeStyle;
+		          absoluteCoordinates: AbsoluteCoordinates frBrest.
 	element addObject: circle.
 	space := self openViewInWindow: element.
 
 	newCenter := AbsoluteCoordinates frBrest copy.
-	[ (1 to: 30) do:[:i | 1 seconds wait.
-		newCenter := AbsoluteCoordinates latitudeInDegrees: (newCenter latitudeInDegrees + 0.05)  longitudeInDegrees: (newCenter longitudeInDegrees + 0.05).
-		element geoCenter: newCenter.
-		circle absoluteCoordinates:newCenter.
-		element updateObjects: (OrderedCollection with: circle).
-		]
-	] forkAt: Processor userBackgroundPriority 
-	
+	[
+		(1 to: 30) do: [ :i |
+				1 seconds wait.
+				newCenter := AbsoluteCoordinates
+					             latitudeInDegrees:
+					             newCenter latitudeInDegrees + 0.05
+					             longitudeInDegrees:
+					             newCenter longitudeInDegrees + 0.05.
+				element geoCenter: newCenter.
+				circle absoluteCoordinates: newCenter.
+				element updateObjects: (OrderedCollection with: circle) ] ]
+		forkAt: Processor userBackgroundPriority
 ]
 
 { #category : #'examples - data' }
diff --git a/src/GeoView-Molecule/GeoViewManagerImpl.class.st b/src/GeoView-Molecule/GeoViewManagerImpl.class.st
index 777e0e7..57b2330 100644
--- a/src/GeoView-Molecule/GeoViewManagerImpl.class.st
+++ b/src/GeoView-Molecule/GeoViewManagerImpl.class.st
@@ -172,6 +172,12 @@ GeoViewManagerImpl >> getGlobalPointFromLocalPoint: aLocalPoint [
 	^ self getView globalPointFromLocalPoint: aLocalPoint 
 ]
 
+{ #category : #'parameters - interactions' }
+GeoViewManagerImpl >> getInteractionsStrategy [
+
+	^ self getView interactionsStrategy 
+]
+
 { #category : #'services - layer' }
 GeoViewManagerImpl >> getLayer: aKey [
 
@@ -208,6 +214,12 @@ GeoViewManagerImpl >> getObjectIndexAccessor [
 	^ self view objectIndexAccessor 
 ]
 
+{ #category : #services }
+GeoViewManagerImpl >> getScale [
+
+	^ self view scale
+]
+
 { #category : #services }
 GeoViewManagerImpl >> getScaleFactor [
 
@@ -217,7 +229,11 @@ GeoViewManagerImpl >> getScaleFactor [
 { #category : #services }
 GeoViewManagerImpl >> getScaleInMeters [
 
-	^ self view scaleInMeters 
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver getScaleInMeters' -> '`@receiver getScale'.
+
+	^ self getScale
 ]
 
 { #category : #'component accessing' }
@@ -449,6 +465,12 @@ GeoViewManagerImpl >> setGeoCenter: anAbsoluteCoordinates [
 	self view geoCenter: anAbsoluteCoordinates
 ]
 
+{ #category : #'parameters - interactions' }
+GeoViewManagerImpl >> setInteractionsStrategy: aStrategy [
+
+	self getView setInteractionsStrategy: aStrategy 
+]
+
 { #category : #'services - map projection' }
 GeoViewManagerImpl >> setMapProjection: aMapProjection [
 
@@ -461,6 +483,12 @@ GeoViewManagerImpl >> setObjectIndexAccessor: aSymbol [
 	self getView objectIndexAccessor: aSymbol 
 ]
 
+{ #category : #services }
+GeoViewManagerImpl >> setScale: aNumber [
+
+	self view scale: aNumber 
+]
+
 { #category : #services }
 GeoViewManagerImpl >> setScaleFactor: aNumber [
 
@@ -470,7 +498,11 @@ GeoViewManagerImpl >> setScaleFactor: aNumber [
 { #category : #services }
 GeoViewManagerImpl >> setScaleInMeters: aNumber [
 
-	self view scaleInMeters: aNumber
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver setScaleInMeters: `@aNumber' -> '`@receiver setScale: `@aNumber'.
+
+	self setScale: aNumber
 ]
 
 { #category : #'parameters - selection manager' }
diff --git a/src/GeoView-Molecule/GeoViewManagerParameters.trait.st b/src/GeoView-Molecule/GeoViewManagerParameters.trait.st
index 0148902..fbeccc6 100644
--- a/src/GeoView-Molecule/GeoViewManagerParameters.trait.st
+++ b/src/GeoView-Molecule/GeoViewManagerParameters.trait.st
@@ -12,6 +12,10 @@ Trait {
 GeoViewManagerParameters >> getDisplayToGraphicProjection [
 ]
 
+{ #category : #'parameters - interactions' }
+GeoViewManagerParameters >> getInteractionsStrategy [
+]
+
 { #category : #'parameters - objects' }
 GeoViewManagerParameters >> getObjectIndexAccessor [
 ]
@@ -24,6 +28,10 @@ GeoViewManagerParameters >> getViewInfos [
 GeoViewManagerParameters >> setDisplayToGraphicProjection: aGeoView2DProjection [
 ]
 
+{ #category : #'parameters - interactions' }
+GeoViewManagerParameters >> setInteractionsStrategy: aStrategy [
+]
+
 { #category : #'parameters - objects' }
 GeoViewManagerParameters >> setObjectIndexAccessor: aSymbol [
 ]
diff --git a/src/GeoView-Molecule/GeoViewManagerServices.trait.st b/src/GeoView-Molecule/GeoViewManagerServices.trait.st
index cdcfed3..a1b2b57 100644
--- a/src/GeoView-Molecule/GeoViewManagerServices.trait.st
+++ b/src/GeoView-Molecule/GeoViewManagerServices.trait.st
@@ -65,11 +65,11 @@ GeoViewManagerServices >> getMapProjection [
 ]
 
 { #category : #services }
-GeoViewManagerServices >> getScaleFactor [
+GeoViewManagerServices >> getScale [
 ]
 
 { #category : #services }
-GeoViewManagerServices >> getScaleInMeters [
+GeoViewManagerServices >> getScaleFactor [
 ]
 
 { #category : #services }
@@ -105,9 +105,9 @@ GeoViewManagerServices >> setMapProjection: aMapProjection [
 ]
 
 { #category : #services }
-GeoViewManagerServices >> setScaleFactor: aNumber [
+GeoViewManagerServices >> setScale: aNumber [
 ]
 
 { #category : #services }
-GeoViewManagerServices >> setScaleInMeters: aNumber [
+GeoViewManagerServices >> setScaleFactor: aNumber [
 ]
diff --git a/src/GeoView-Tests/AbstractGeoViewGraphicModelLayerTest.class.st b/src/GeoView-Tests/AbstractGeoViewGraphicModelLayerTest.class.st
index 4ba146d..09cd20a 100644
--- a/src/GeoView-Tests/AbstractGeoViewGraphicModelLayerTest.class.st
+++ b/src/GeoView-Tests/AbstractGeoViewGraphicModelLayerTest.class.st
@@ -12,6 +12,7 @@ Class {
 
 { #category : #running }
 AbstractGeoViewGraphicModelLayerTest >> setUp [
+
 	super setUp.
 
 	layer := AbstractGeoViewGraphicModelLayer new
@@ -144,6 +145,7 @@ AbstractGeoViewGraphicModelLayerTest >> testNeedToSortDatas [
 AbstractGeoViewGraphicModelLayerTest >> testReachMaximumDisplayedObjects [
 
 	| objects |
+	layer graphicProjection: (GeoView2DProjection new resolution: (10 asPoint)).
 	layer maximumDisplayedObjects: 50.
 	
 	objects := (1 to: 100) collect:[ :e | SmockDCircle new key: e; radius: 10; coordinates: 0@0; fillColor: Color red ].
diff --git a/src/GeoView-Tests/GeoView2DProjectionTest.class.st b/src/GeoView-Tests/GeoView2DProjectionTest.class.st
index eec7a24..30baa53 100644
--- a/src/GeoView-Tests/GeoView2DProjectionTest.class.st
+++ b/src/GeoView-Tests/GeoView2DProjectionTest.class.st
@@ -18,17 +18,6 @@ GeoView2DProjectionTest >> setUp [
 	projection := GeoView2DProjection new
 ]
 
-{ #category : #tests }
-GeoView2DProjectionTest >> testAltitudeInMeters [
-
-	self assert: projection altitudeInMeters equals: (projection defaultAltitudeInMeters).
-	
-	projection altitudeInMeters: 1.
-	self assert: projection altitudeInMeters equals: 1.	
-	
-	
-]
-
 { #category : #tests }
 GeoView2DProjectionTest >> testBoundsInPixels [
 
@@ -53,10 +42,10 @@ GeoView2DProjectionTest >> testExtentInPixels [
 { #category : #tests }
 GeoView2DProjectionTest >> testMetersByPixel [
 
-	self assert: projection metersByPixel equals: 0@0.
+	self assert: projection metersByPixel equals: 0.
 	
-	projection metersByPixel: 1 asPoint.
-	self assert: projection metersByPixel equals: 1 asPoint.
+	projection resolution: 1 asPoint.
+	self assert: projection metersByPixel equals: 1.
 	
 	
 ]
@@ -71,3 +60,42 @@ GeoView2DProjectionTest >> testOffsetInPixels [
 	
 	
 ]
+
+{ #category : #tests }
+GeoView2DProjectionTest >> testScale [
+
+	self assert: projection scale isNil.
+	
+	projection scale: 1.
+	self assert: projection scale equals: 1.	
+	
+	
+]
+
+{ #category : #tests }
+GeoView2DProjectionTest >> testUpdateResolution [
+
+	"not supported values"
+	projection updateResolution: nil.
+	self assert: projection resolution equals: 0 asPoint.
+	
+	projection updateResolution: 1.
+	self assert: projection resolution equals: 0 asPoint.
+	
+	projection updateResolution: 100@100.
+	self assert: projection resolution equals: 0 asPoint.
+	
+	"setup a scale to update"
+	projection scale: 1000000.
+	
+	"not supported values"
+	projection updateResolution: nil.
+	self assert: projection resolution equals: 0 asPoint.
+	
+	projection updateResolution: 1.
+	self assert: projection resolution equals: 0 asPoint.
+	
+	"supported values"
+	projection updateResolution: 100@100.
+	self assert: projection resolution equals: (1/20000 asPoint).
+]
diff --git a/src/GeoView-Tests/GeoViewAbstractElementTest.class.st b/src/GeoView-Tests/GeoViewAbstractElementTest.class.st
index 6ed08b8..0aa3cf2 100644
--- a/src/GeoView-Tests/GeoViewAbstractElementTest.class.st
+++ b/src/GeoView-Tests/GeoViewAbstractElementTest.class.st
@@ -204,12 +204,47 @@ GeoViewAbstractElementTest >> testInteractionsStrategy [
 	self assert: geoView interactionsStrategy class equals: GeoViewInteractionsStrategy
 ]
 
+{ #category : #tests }
+GeoViewAbstractElementTest >> testMaxScale [
+
+	self assert: geoView maxScale equals: 100000000.
+	
+	geoView maxScale: 10000000.
+	self assert: geoView maxScale equals: 10000000.
+]
+
+{ #category : #tests }
+GeoViewAbstractElementTest >> testMinScale [
+
+	self assert: geoView minScale equals: 100.
+	
+	geoView minScale: 500.
+	self assert: geoView minScale equals: 500.
+]
+
 { #category : #tests }
 GeoViewAbstractElementTest >> testNewInteractionsStrategy [
 
 	self assert: geoView newInteractionsStrategy class equals: GeoViewInteractionsStrategy.
 ]
 
+{ #category : #tests }
+GeoViewAbstractElementTest >> testNormalizeScale [
+
+	"Min"
+	self assert: (geoView normalizeScale: geoView minScale) equals: (geoView minScale).
+	self assert: (geoView normalizeScale: 100) equals: 100.
+	self assert: (geoView normalizeScale: 1) equals: 100.
+	
+	"Max"
+	self assert: (geoView normalizeScale: geoView maxScale) equals: (geoView maxScale).
+	self assert: (geoView normalizeScale: 100000000) equals: 100000000.
+	self assert: (geoView normalizeScale: 1000000000) equals: 100000000.
+	
+	"Middle"
+	self assert: (geoView normalizeScale: 10000) equals: 10000.
+]
+
 { #category : #tests }
 GeoViewAbstractElementTest >> testObjectIndexAccessor [
 
@@ -316,6 +351,38 @@ GeoViewAbstractElementTest >> testRemoveLayer [
 	self assert: (geoView getLayer: #test) isNil
 ]
 
+{ #category : #tests }
+GeoViewAbstractElementTest >> testScale [
+
+	self assert: geoView scale equals: geoView defaultScale.
+	
+	geoView scale: 100000.
+	self assert: geoView scale equals: 100000
+]
+
+{ #category : #tests }
+GeoViewAbstractElementTest >> testScaleDown [
+	
+	geoView scaleDown.
+	self assert: geoView scale equals: (geoView defaultScale * geoView scaleFactor).
+]
+
+{ #category : #tests }
+GeoViewAbstractElementTest >> testScaleFactor [
+
+	self assert: geoView scaleFactor equals: 1.5.
+	
+	geoView scaleFactor: 2.
+	self assert: geoView scaleFactor equals: 2
+]
+
+{ #category : #tests }
+GeoViewAbstractElementTest >> testScaleUp [
+	
+	geoView scaleUp.
+	self assert: geoView scale equals: (geoView defaultScale / geoView scaleFactor).
+]
+
 { #category : #tests }
 GeoViewAbstractElementTest >> testSetInteractionsStrategy [
 
diff --git a/src/GeoView-Tests/GeoViewAeElementTest.class.st b/src/GeoView-Tests/GeoViewAeElementTest.class.st
index 500cb2f..3fc4240 100644
--- a/src/GeoView-Tests/GeoViewAeElementTest.class.st
+++ b/src/GeoView-Tests/GeoViewAeElementTest.class.st
@@ -171,7 +171,7 @@ GeoViewAeElementTest >> testCreateAndRemoveObjectOnHiddenLayer [
 	] delay: 5 milliSeconds) start; yourself.
 
 	"waiting here to simulate user interaction a lot of time"
-	4 seconds wait.
+	2 seconds wait.
 	
 	"stop tasks"
 	updateTask kill.
@@ -183,8 +183,8 @@ GeoViewAeElementTest >> testCreateAndRemoveObjectOnHiddenLayer [
 	uiTask stop.
 	
 	"waiting for last pulses"
-	0.5 seconds wait.
 	spacePulseTask stop.
+	1 seconds wait.
 		
 	"test to compare list model and graphic model"
 	self assert: (layer displayModel getDatas size) equals: 0.
@@ -228,8 +228,8 @@ GeoViewAeElementTest >> testCreateUpdateRemoveObjects [
 	uiTask stop.
 	
 	"waiting for last pulses"
-	0.5 seconds wait.
 	spacePulseTask stop.
+	1 seconds wait.
 		
 	"test to compare list model and graphic model"
 	self assert: (layer displayModel getDatas size) equals: (list size).
diff --git a/src/GeoView-Tests/GeoViewProjectionChangesTest.class.st b/src/GeoView-Tests/GeoViewProjectionChangesTest.class.st
index da2d2ac..c6d5b9e 100644
--- a/src/GeoView-Tests/GeoViewProjectionChangesTest.class.st
+++ b/src/GeoView-Tests/GeoViewProjectionChangesTest.class.st
@@ -15,6 +15,5 @@ GeoViewProjectionChangesTest >> testInitialize [
 	self deny: changes isCenterChanged.
 	self deny: changes isExtentChanged.
 	self deny: changes isMapProjectionChange.
-	self deny: changes isResolutionChanged.
 	self deny: changes isScaleChanged.
 ]
diff --git a/src/GeoView/GeoView2DProjection.class.st b/src/GeoView/GeoView2DProjection.class.st
index 1dce0ee..5259c94 100644
--- a/src/GeoView/GeoView2DProjection.class.st
+++ b/src/GeoView/GeoView2DProjection.class.st
@@ -9,9 +9,10 @@ Class {
 	#classTraits : 'TGeoViewGraphicProjection classTrait',
 	#instVars : [
 		'cartesianCenter',
-		'altitudeInMeters',
 		'metersByPixel',
-		'offsetInPixels'
+		'offsetInPixels',
+		'scale',
+		'resolution'
 	],
 	#category : #'GeoView-Core'
 }
@@ -19,14 +20,15 @@ Class {
 { #category : #accessing }
 GeoView2DProjection >> altitudeInMeters [
 
-	^ altitudeInMeters ifNil: [
-		  altitudeInMeters := self defaultAltitudeInMeters ]
+	self deprecated:'use scale'.
+	^ self scale
 ]
 
 { #category : #accessing }
 GeoView2DProjection >> altitudeInMeters: aNumber [
 
-	altitudeInMeters := aNumber
+	self deprecated:'use scale:'.
+	self scale: aNumber
 ]
 
 { #category : #accessing }
@@ -48,10 +50,15 @@ GeoView2DProjection >> cartesianCenter: aCartesianCoordinates [
 	cartesianCenter := aCartesianCoordinates
 ]
 
-{ #category : #initialization }
-GeoView2DProjection >> defaultAltitudeInMeters [
+{ #category : #private }
+GeoView2DProjection >> computeResolution: aNumber [
 
-	^ 1.4816e7
+	| viewHeight mapHeight |
+	viewHeight := aNumber.
+	mapHeight := 2 * self scale.
+	mapHeight = 0 ifTrue: [ mapHeight := 1 ].
+
+	^ (viewHeight / mapHeight) asPoint
 ]
 
 { #category : #accessing }
@@ -60,17 +67,6 @@ GeoView2DProjection >> extentInPixels [
 	^ self offsetInPixels * 2
 ]
 
-{ #category : #accessing }
-GeoView2DProjection >> haveResolution: aViewSize [
-
-	| viewHeight mapHeight |
-	viewHeight := aViewSize y.
-	mapHeight := 2 * self altitudeInMeters.
-	mapHeight = 0 ifTrue:[ mapHeight := 1 ].
-	
-	^ self metersByPixel = (viewHeight / mapHeight)
-]
-
 { #category : #accessing }
 GeoView2DProjection >> key [
 
@@ -79,20 +75,15 @@ GeoView2DProjection >> key [
 
 { #category : #accessing }
 GeoView2DProjection >> metersByPixel [
+	"By default return x value of the resolution"
 
-	^ metersByPixel ifNil: [ metersByPixel := 0 @ 0 ]
-]
-
-{ #category : #accessing }
-GeoView2DProjection >> metersByPixel: aNumber [
-
-	metersByPixel := aNumber
+	^ self resolution x
 ]
 
 { #category : #accessing }
 GeoView2DProjection >> offsetInPixels [
 
-	^ offsetInPixels ifNil: [ offsetInPixels := 0 @ 0 ]
+	^ offsetInPixels ifNil: [ offsetInPixels := 0 asPoint ]
 ]
 
 { #category : #accessing }
@@ -111,7 +102,7 @@ GeoView2DProjection >> projCartToPixel: aCartesianCoordinates [
 	point := aCartesianCoordinates asPoint.
 	geoCenter := self cartesianCenter asPoint.
 	pixel := ((point x @ point y negated) - (geoCenter x @ geoCenter y negated))
-		* self metersByPixel
+		* self resolution
 		+ self offsetInPixels.
 	^ pixel
 ]
@@ -119,7 +110,7 @@ GeoView2DProjection >> projCartToPixel: aCartesianCoordinates [
 { #category : #projection }
 GeoView2DProjection >> projPixelToCart: aPoint [
 
-	| xCartesian yCartesian xOffset yOffset scale |
+	| xCartesian yCartesian xOffset yOffset resX resY |
 	
 	"Calculate the X offset from the center of the view"
     xOffset := aPoint x - self offsetInPixels x.
@@ -127,27 +118,48 @@ GeoView2DProjection >> projPixelToCart: aPoint [
 	"Calculate the Y offset from the center of the view, reversing the Y direction"
     yOffset := self offsetInPixels y - aPoint y.
 	
-	 "Calculate the Cartesian coordinates based on the center of the view and the scale"
-	scale := self metersByPixel.
-	scale = 0 ifTrue:[
-		xCartesian := xOffset + self cartesianCenter xInMeters.
-  	 	yCartesian := yOffset + self cartesianCenter yInMeters.
-	] ifFalse:[
-		xCartesian := (xOffset / scale) + self cartesianCenter xInMeters.
-  	 	yCartesian := (yOffset / scale) + self cartesianCenter yInMeters.
-	].
+	 "Calculate the Cartesian coordinates based on the center of the view and the resolution"
+	resX := (self resolution x = 0 ifTrue:[ 1 ] ifFalse:[ self resolution x ]).
+	resY := (self resolution y = 0 ifTrue:[ 1 ] ifFalse:[ self resolution y ]).
+	
+	xCartesian := (xOffset / (resX)) + self cartesianCenter xInMeters.
+  	yCartesian := (yOffset / (resY)) + self cartesianCenter yInMeters.
 	
 	^ CartesianCoordinates xInMeters: xCartesian yInMeters: yCartesian
 ]
 
 { #category : #accessing }
-GeoView2DProjection >> updateResolution: aPoint [
-	| viewHeight mapHeight |
-	
-	self assert: [aPoint isNotNil] description: ['[GeoView] 2D projection view size cannot be nil.'].
-	viewHeight := aPoint y.
-	mapHeight := 2 * self altitudeInMeters.
-	mapHeight = 0 ifTrue:[ mapHeight := 1 ].
-	
-	self metersByPixel: viewHeight / mapHeight. 
+GeoView2DProjection >> resolution [
+
+	^ resolution ifNil: [ resolution := 0 asPoint ]
+]
+
+{ #category : #accessing }
+GeoView2DProjection >> resolution: aPoint [
+
+	resolution := aPoint
+]
+
+{ #category : #accessing }
+GeoView2DProjection >> scale [
+
+	^ scale
+]
+
+{ #category : #accessing }
+GeoView2DProjection >> scale: aNumber [
+
+	scale := aNumber
+]
+
+{ #category : #update }
+GeoView2DProjection >> updateResolution: aViewSize [
+
+	| res |
+	aViewSize ifNil: [ ^ self ].
+	aViewSize isPoint ifFalse:[ ^ self ].
+	self scale ifNil:[ ^ self ].
+
+	res := self computeResolution: aViewSize y.
+	self resolution: res
 ]
diff --git a/src/GeoView/GeoViewAbstractElement.class.st b/src/GeoView/GeoViewAbstractElement.class.st
index 67472d4..a65bf51 100644
--- a/src/GeoView/GeoViewAbstractElement.class.st
+++ b/src/GeoView/GeoViewAbstractElement.class.st
@@ -7,16 +7,16 @@ Class {
 	#instVars : [
 		'geoCenter',
 		'scaleFactor',
-		'maxScaleInMeters',
-		'minScaleInMeters',
-		'scaleInMeters',
 		'objectIndexAccessor',
 		'layers',
 		'displayToGraphicProjection',
 		'mapProjection',
 		'viewInfos',
 		'interactionsStrategy',
-		'displayFilter'
+		'displayFilter',
+		'scale',
+		'maxScale',
+		'minScale'
 	],
 	#category : #'GeoView-Core'
 }
@@ -174,6 +174,13 @@ GeoViewAbstractElement >> createPickingResultAt: aGlobalPoint [
 	^ pickingResult
 ]
 
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> defaultScale [
+	"Default scale is 1:10 000 000"
+
+	^ 10000000
+]
+
 { #category : #'API -- filters' }
 GeoViewAbstractElement >> displayFilter [
 
@@ -199,8 +206,8 @@ GeoViewAbstractElement >> displayToGraphicProjection: aGeoView2DProjection [
 
 	displayToGraphicProjection := aGeoView2DProjection.
 	displayToGraphicProjection ifNil: [ ^ self ].
-	
-	"change projection to layers"
+
+	"inject the projection to all layers"
 	self layers do:[ :l | l graphicProjection: displayToGraphicProjection ].
 	
 	self updateDisplayToGraphicProjection
@@ -213,19 +220,10 @@ GeoViewAbstractElement >> doPicking: aPickingResult [
 	self getLayers do: [ :l | l isVisible ifTrue: [ l populatePickingResult: aPickingResult ] ]
 ]
 
-{ #category : #private }
-GeoViewAbstractElement >> evaluateScale: aNumberInMeters [
-
-	aNumberInMeters < self minScaleInMeters ifTrue: [ ^ self minScaleInMeters ].
-	aNumberInMeters > self maxScaleInMeters ifTrue: [ ^ self maxScaleInMeters ].
-	^ aNumberInMeters 
-]
-
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> geoCenter [
 
-	geoCenter ifNil: [ geoCenter := AbsoluteCoordinates zero ].
-	^ geoCenter
+	^ geoCenter ifNil: [ geoCenter := AbsoluteCoordinates zero ]
 ]
 
 { #category : #'API -- scale and center' }
@@ -297,11 +295,18 @@ GeoViewAbstractElement >> haveObjectIndex: anIndex [
 GeoViewAbstractElement >> initialize [
 
 	super initialize.
-
+	
+	"Initialize default projection systems"
 	self mapProjection: GeoViewMercatorProjection new.
 	self displayToGraphicProjection: GeoView2DProjection new.
+	self scale: self defaultScale.
+	
+	"Initialize events handlers"
+	self initializeEventHandlers.
+	
+	"Bloc customization"
 	self background: Color black.
-	self initializeEventHandlers
+	
 ]
 
 { #category : #initialization }
@@ -407,28 +412,70 @@ GeoViewAbstractElement >> mapProjection: aMapProjection [
 	self dispatchEvent: geoViewEvent
 ]
 
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> maxScale [
+	"Default maximum scale is 1:100 000 000"
+
+	^ maxScale ifNil: [ maxScale := 100000000 ]
+]
+
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> maxScale: aNumber [
+
+	maxScale := aNumber
+]
+
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> maxScaleInMeters [
 
-	^ maxScaleInMeters ifNil: [ maxScaleInMeters := 1.5171584e7 ]
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver maxScaleInMeters' -> '`@receiver maxScale'.
+
+	^ self maxScale
+]
+
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> maxScaleInMeters: aNumber [
+
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver maxScaleInMeters: `@aNumber' -> '`@receiver maxScale: `@aNumber'.
+
+	self maxScale: aNumber
+]
+
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> minScale [
+	"Default minimum scale is 1:100"
+
+	^ minScale ifNil: [ minScale := 100 ]
 ]
 
 { #category : #'API -- scale and center' }
-GeoViewAbstractElement >> maxScaleInMeters: anObject [
+GeoViewAbstractElement >> minScale: aNumber [
 
-	maxScaleInMeters := anObject
+	minScale := aNumber
 ]
 
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> minScaleInMeters [
+	
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver minScaleInMeters' -> '`@receiver minScale'.
 
-	^ minScaleInMeters ifNil: [ minScaleInMeters := 1852.0 ]
+	^ self minScale
 ]
 
 { #category : #'API -- scale and center' }
-GeoViewAbstractElement >> minScaleInMeters: anObject [
+GeoViewAbstractElement >> minScaleInMeters: aNumber [
+
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver minScaleInMeters: `@aNumber' -> '`@receiver minScale: `@aNumber'.
 
-	minScaleInMeters := anObject
+	self minScale: aNumber
 ]
 
 { #category : #'strategy management' }
@@ -437,6 +484,14 @@ GeoViewAbstractElement >> newInteractionsStrategy [
 	^ GeoViewInteractionsStrategy new
 ]
 
+{ #category : #private }
+GeoViewAbstractElement >> normalizeScale: aNumberInMeters [
+
+	aNumberInMeters < self minScale ifTrue: [ ^ self minScale ].
+	aNumberInMeters > self maxScale ifTrue: [ ^ self maxScale ].
+	^ aNumberInMeters
+]
+
 { #category : #'API -- objects management' }
 GeoViewAbstractElement >> objectIndexAccessor [
 
@@ -566,16 +621,42 @@ GeoViewAbstractElement >> requestRepaint [
 	self invalidate
 ]
 
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> scale [
+
+	^ scale
+]
+
+{ #category : #'API -- scale and center' }
+GeoViewAbstractElement >> scale: aNumber [
+
+	| newScale geoViewEvent |
+	newScale := self normalizeScale: aNumber.
+	
+	scale = newScale ifTrue:[ ^ self ].
+	scale := newScale.
+	
+	self updateDisplayToGraphicProjection.
+	
+	"Send scale event"
+	geoViewEvent := GeoViewScaleChangedEvent new.
+	geoViewEvent scale: self scale.
+	self dispatchEvent: geoViewEvent.
+]
+
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> scaleDown [
 
-	self scaleInMeters: self scaleInMeters * self scaleFactor
+	self scale: (self scale * self scaleFactor)
 ]
 
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> scaleFactor [
+	"The scale factor is the multiplicator / diviser for default zoom up/down"
 
-	^ scaleFactor ifNil: [ scaleFactor := 2 ]
+	(scaleFactor = 0 or: [ scaleFactor isNil ]) ifTrue: [
+		scaleFactor := 1.5 ].
+	^ scaleFactor
 ]
 
 { #category : #'API -- scale and center' }
@@ -587,30 +668,27 @@ GeoViewAbstractElement >> scaleFactor: aNumber [
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> scaleInMeters [
 
-	^ scaleInMeters ifNil: [ scaleInMeters := 1.4816e7 ]
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver scaleInMeters' -> '`@receiver scale'.
+
+	^ self scale
 ]
 
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> scaleInMeters: aNumber [
 
-	| scale geoViewEvent |
-	scale := self evaluateScale: aNumber.
-	scaleInMeters := scale.
-	
-	self displayToGraphicProjection altitudeInMeters: self scaleInMeters.
-	self displayToGraphicProjection updateResolution: self extent.
-	self updateModel: ((GeoViewProjectionChanges new) isScaleChanged: true; isResolutionChanged: true; yourself).
-	
-	"Send scale event"
-	geoViewEvent := GeoViewScaleChangedEvent new.
-	geoViewEvent scaleInMeters: self scaleInMeters.
-	self dispatchEvent: geoViewEvent.
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver scaleInMeters: `@aNumber' -> '`@receiver scale: `@aNumber'.
+		
+	self scale: aNumber
 ]
 
 { #category : #'API -- scale and center' }
 GeoViewAbstractElement >> scaleUp [
 
-	self scaleInMeters: self scaleInMeters / self scaleFactor
+	self scale: (self scale / self scaleFactor)
 ]
 
 { #category : #'API -- selection' }
@@ -644,19 +722,29 @@ GeoViewAbstractElement >> unconfigureLayer: aLayer [
 { #category : #private }
 GeoViewAbstractElement >> updateDisplayToGraphicProjection [
 
-	| extent offset |
+	| extent offset changes |
+	"cannot update when scale is not defined, initialize it before"
+	self scale ifNil:[ ^ self ].
 	extent := self viewInfos extent.
+	extent = (0@0) ifTrue:[ ^ self ]. 
 	offset := extent / 2.
 
-	(self displayToGraphicProjection offsetInPixels ~= offset or: [
-		 (self displayToGraphicProjection haveResolution: extent) not ])
-		ifFalse: [ ^ self ].
-		
-	self displayToGraphicProjection offsetInPixels: offset.
-	self displayToGraphicProjection updateResolution: extent.
-	self updateModel: (GeoViewProjectionChanges new
-			 isExtentChanged: true;
-			 isResolutionChanged: true)
+	changes := GeoViewProjectionChanges new.
+
+	self displayToGraphicProjection offsetInPixels ~= offset ifTrue:[
+		self displayToGraphicProjection offsetInPixels: offset.
+		changes isExtentChanged: true.
+	].
+	
+	"Check if need to update the scale of the graphic projection when scale are differents"
+	self scale ~= self displayToGraphicProjection scale ifTrue:[
+		self displayToGraphicProjection scale: self scale.
+		self displayToGraphicProjection updateResolution: extent.	
+		changes isScaleChanged: true.
+	].
+
+	( changes isExtentChanged or:[ changes isScaleChanged ]) ifFalse:[ ^ self ].	
+	self updateModel: changes
 ]
 
 { #category : #private }
diff --git a/src/GeoView/GeoViewMapTilesLayer.class.st b/src/GeoView/GeoViewMapTilesLayer.class.st
index b5f851c..b6ed8a5 100644
--- a/src/GeoView/GeoViewMapTilesLayer.class.st
+++ b/src/GeoView/GeoViewMapTilesLayer.class.st
@@ -150,7 +150,7 @@ GeoViewMapTilesLayer >> doLoadingTilesThread [
 
 	| centerGeoPoint level tilesXY tilesXYBuffer findAtLeastOneTile realLevel|
 
-	self previousScale: currentGraphicProjection altitudeInMeters.
+	self previousScale: currentGraphicProjection scale.
 	self surfaceMap offcenter: self mapOffcenter.
 	self surfaceMap scale: 1@1.
 
diff --git a/src/GeoView/GeoViewProjectionChanges.class.st b/src/GeoView/GeoViewProjectionChanges.class.st
index 43fbc81..499ba26 100644
--- a/src/GeoView/GeoViewProjectionChanges.class.st
+++ b/src/GeoView/GeoViewProjectionChanges.class.st
@@ -57,12 +57,20 @@ GeoViewProjectionChanges >> isProjectionChanges [
 { #category : #accessing }
 GeoViewProjectionChanges >> isResolutionChanged [
 
+	self 
+		deprecated:'This is a scale changed' 
+		transformWith: '`@receiver isResolutionChanged' -> '`@receiver isScaleChanged'.
+		
 	^ isResolutionChanged ifNil: [ isResolutionChanged := false ]
 ]
 
 { #category : #accessing }
 GeoViewProjectionChanges >> isResolutionChanged: anObject [
 
+	self 
+		deprecated:'This is a scale changed' 
+		transformWith: '`@receiver isResolutionChanged: `@anObject' -> '`@receiver isScaleChanged: `@anObject'.
+		
 	isResolutionChanged := anObject
 ]
 
diff --git a/src/GeoView/GeoViewScaleChangedEvent.class.st b/src/GeoView/GeoViewScaleChangedEvent.class.st
index 0b02d05..0882a64 100644
--- a/src/GeoView/GeoViewScaleChangedEvent.class.st
+++ b/src/GeoView/GeoViewScaleChangedEvent.class.st
@@ -2,21 +2,41 @@ Class {
 	#name : #GeoViewScaleChangedEvent,
 	#superclass : #GeoViewEvent,
 	#instVars : [
-		'scaleInMeters'
+		'scale'
 	],
 	#category : #'GeoView-Events'
 }
 
+{ #category : #accessing }
+GeoViewScaleChangedEvent >> scale [
+
+	^ scale
+]
+
+{ #category : #accessing }
+GeoViewScaleChangedEvent >> scale: aNumber [
+
+	scale := aNumber
+]
+
 { #category : #accessing }
 GeoViewScaleChangedEvent >> scaleInMeters [
 
-	^ scaleInMeters
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver scaleInMeters' -> '`@receiver scale'.
+
+	^ self scale
 ]
 
 { #category : #accessing }
-GeoViewScaleChangedEvent >> scaleInMeters: anObject [
+GeoViewScaleChangedEvent >> scaleInMeters: aNumber [
+
+	self 
+		deprecated:'Use generic message' 
+		transformWith: '`@receiver scaleInMeters: `@aNumber' -> '`@receiver scale: `@aNumber'.
 
-	scaleInMeters := anObject
+	self scale: aNumber
 ]
 
 { #category : #sending }