diff --git a/pkg/bitmap/bitmap.go b/pkg/bitmap/bitmap.go
index 4569e02..4b6a106 100644
--- a/pkg/bitmap/bitmap.go
+++ b/pkg/bitmap/bitmap.go
@@ -84,9 +84,9 @@ func (p bitmap) SetFreeN(number int) error {
 	return fmt.Errorf("set free pixel: no such number=%d, max=%d", number, n)
 }
 
-func (p bitmap) Circle(x, y int, r float64, fill bool) {
+func (p bitmap) Circle(x, y int, r float32, fill bool) {
 	plotX := 0
-	plotY := int(math.Ceil(r))
+	plotY := int(math.Ceil(float64(r)))
 	delta := 3 - 2*plotY
 	lastY := plotY
 	for plotX <= plotY {
diff --git a/pkg/bitmap/bitmap_test.go b/pkg/bitmap/bitmap_test.go
index d294ddc..df8d8b6 100644
--- a/pkg/bitmap/bitmap_test.go
+++ b/pkg/bitmap/bitmap_test.go
@@ -221,7 +221,7 @@ func TestClear(t *testing.T) {
 func TestCircle(t *testing.T) {
 	type testCase struct {
 		x, y   int
-		r      float64
+		r      float32
 		filled bool
 	}
 	for i, tc := range []testCase{
diff --git a/pkg/generator/generator.go b/pkg/generator/generator.go
index 2301ab5..806260d 100644
--- a/pkg/generator/generator.go
+++ b/pkg/generator/generator.go
@@ -4,146 +4,73 @@ import (
 	"fmt"
 	"math"
 	"math/rand"
-
-	"github.com/iliadenisov/galaxy/pkg/bitmap"
 )
 
-type Map struct {
-	Width       uint
-	Height      uint
-	HomePlanets []PlanetarySystem
-	FreePlanets []Planet
-	plotter     Plotter
-}
-
-type Coordinate struct {
-	X, Y float64
-}
-
-type Planet struct {
-	Position  Coordinate
-	Size      float64
-	Resources float64 // Сырьё
-}
-
-type PlanetarySystem struct {
-	HW Planet
-	DW []Planet
-}
-
-type Plotter struct {
-	factor              float64
-	clearFn             func()
-	circleFn            func(x, y int, r float64)
-	freeCountFn         func() int
-	freeNumberToCoordFn func(int) (int, int)
-}
-
-func Generate(param MapParameter) (result Map) {
-	pl := func(c Coordinate, param UninhabitedPlanetParameters) Planet {
+func Generate(ms MapSetting) (Map, error) {
+	pl := func(c Coordinate, ps PlanetSetting) Planet {
 		return Planet{
 			Position:  c,
-			Size:      param.MinSize + rand.Float64()*(param.MaxSize-param.MinSize),
-			Resources: float64(param.MinResource) + rand.Float64()*(param.MaxResource-param.MinResource)}
+			Size:      ps.MinSize + rand.Float32()*(ps.MaxSize-ps.MinSize),
+			Resources: float32(ps.MinResource) + rand.Float32()*(ps.MaxResource-ps.MinResource)}
 	}
 	// mapSize := uint(math.Ceil(math.Sqrt(float64(param.Players)))) * param.HW_MinDistance
 	var mapSize uint = 200
 
-	result = NewMap(mapSize, mapSize, param.Players)
+	result, err := NewMap(mapSize, mapSize, ms.Players)
+	if err != nil {
+		return Map{}, fmt.Errorf("NewMap: %s", err)
+	}
 
-	totalPlanets := param.Players * 10
-	freePlanets := totalPlanets - param.Players*(param.DW_Count+1)
+	totalPlanets := ms.Players * 10
+	freePlanets := totalPlanets - ms.Players*(ms.DWCount+1)
 
-	fmt.Println("map:", mapSize, "players:", param.Players, "planets:", totalPlanets, "uninhabited:", freePlanets)
+	fmt.Println("map:", mapSize, "players:", ms.Players, "planets:", totalPlanets, "uninhabited:", freePlanets)
 
-	giantsNum := int(math.Ceil(float64(freePlanets) * param.GiantPlanets.Probability))
+	giantsNum := int(math.Ceil(float64(freePlanets) * float64(ms.GiantPlanets.Probability)))
 	fmt.Println("generating", giantsNum, "giant planets")
-	for i := 0; i < giantsNum; i++ {
-		coord := result.newPlanet(float64(param.GiantPlanets.MinDistanceHW))
-		planet := pl(coord, param.GiantPlanets)
-		result.addPlanet(planet)
-		// result.FreePlanets = append(result.FreePlanets, planet)
+	for range giantsNum {
+		coord, err := result.NewCoordinate(float32(ms.GiantPlanets.MinDistanceHW))
+		if err != nil {
+			return Map{}, err
+		}
+		planet := pl(coord, ms.GiantPlanets)
+		result.AddPlanet(planet)
 	}
 
-	bigsNum := int(math.Ceil(float64(freePlanets) * param.BigPlanets.Probability))
+	bigsNum := int(math.Ceil(float64(freePlanets) * float64(ms.BigPlanets.Probability)))
 	fmt.Println("generating", bigsNum, "big planets")
-	for i := 0; i < bigsNum; i++ {
-		coord := result.newPlanet(float64(param.BigPlanets.MinDistanceHW))
-		planet := pl(coord, param.BigPlanets)
-		result.addPlanet(planet)
+	for range bigsNum {
+		coord, err := result.NewCoordinate(float32(ms.BigPlanets.MinDistanceHW))
+		if err != nil {
+			return Map{}, err
+		}
+		planet := pl(coord, ms.BigPlanets)
+		result.AddPlanet(planet)
 	}
 
-	for player := 0; player < int(param.Players); player++ {
+	for player := 0; player < int(ms.Players); player++ {
 		fmt.Println("generating HW #", player)
-		coord := result.newPlanet(float64(param.HW_MinDistance))
-		planet := Planet{Position: coord, Size: float64(param.HW_Size), Resources: float64(param.HW_Resources)}
+		coord, err := result.NewCoordinate(float32(ms.HWMinDistance))
+		if err != nil {
+			return Map{}, err
+		}
+		planet := Planet{Position: coord, Size: float32(ms.HWSize), Resources: float32(ms.HWResources)}
 		result.HomePlanets[player] = PlanetarySystem{HW: planet}
 	}
 
 	result.plotter.clearFn()
 
-	for _, hw := range result.HomePlanets {
-		result.plotter.markNoGoZone(hw.HW.Position.X, hw.HW.Position.Y, 5)
-		for _, dw := range hw.DW {
-			result.plotter.markNoGoZone(dw.Position.X, dw.Position.Y, 5)
+	for i := range result.HomePlanets {
+		result.plotter.MarkDeadZone(result.HomePlanets[i].HW.Position.X, result.HomePlanets[i].HW.Position.Y, 5)
+		for j := range result.HomePlanets[i].DW {
+			result.plotter.MarkDeadZone(result.HomePlanets[i].DW[j].Position.X, result.HomePlanets[i].DW[j].Position.Y, 5)
 		}
 	}
 
-	for _, planet := range result.FreePlanets {
-		result.plotter.markNoGoZone(planet.Position.X, planet.Position.Y, 5)
+	for i := range result.FreePlanets {
+		result.plotter.MarkDeadZone(result.FreePlanets[i].Position.X, result.FreePlanets[i].Position.Y, 5)
 
 	}
 
-	return
-}
-
-func (m Map) newPlanet(deadZoneRaduis float64) Coordinate {
-	fsCount := m.plotter.freeCountFn()
-	if fsCount == 0 {
-		panic("no more space for planets")
-	}
-	next := rand.Intn(fsCount)
-	x, y := m.plotter.freeNumberToCoordFn(next)
-	fmt.Println("planet on plot: x =", x, "y =", y)
-	planetX := float64(x)*m.plotter.factor + rand.Float64()*m.plotter.factor
-	planetY := float64(y)*m.plotter.factor + rand.Float64()*m.plotter.factor
-	m.plotter.markDeadZone(int(x), int(y), deadZoneRaduis)
-	return Coordinate{X: planetX, Y: planetY}
-}
-
-func (m *Map) addPlanet(planet Planet) {
-	m.FreePlanets = append(m.FreePlanets, planet)
-}
-
-func (p Plotter) markNoGoZone(x, y float64, radius float64) { // TODO: test
-	p.markDeadZone(int(x/p.factor), int(y/p.factor), radius)
-}
-
-func (p Plotter) markDeadZone(x, y int, radius float64) {
-	p.circleFn(x, y, radius)
-}
-
-func NewMap(width, height, players uint) Map {
-	var factor float64 = 1.0
-	sectorsX := uint32(float64(width) / factor)
-	sectorsY := uint32(float64(height) / factor)
-	bm := bitmap.NewBitmap(sectorsX, sectorsY)
-	return Map{
-		Width:       width,
-		Height:      height,
-		HomePlanets: make([]PlanetarySystem, players),
-		plotter: Plotter{
-			factor:      factor,
-			clearFn:     bm.Clear,
-			circleFn:    func(x, y int, r float64) { bm.Circle(x, y, r, true) },
-			freeCountFn: bm.FreeCount,
-			freeNumberToCoordFn: func(n int) (x int, y int) {
-				x, y, err := bm.GetFreeN(n)
-				if err != nil {
-					panic(err)
-				}
-				return
-			},
-		},
-	}
+	return *result, nil
 }
diff --git a/pkg/generator/generator_test.go b/pkg/generator/generator_test.go
index 9e61687..d527dca 100644
--- a/pkg/generator/generator_test.go
+++ b/pkg/generator/generator_test.go
@@ -7,5 +7,5 @@ import (
 )
 
 func Test_Generator(t *testing.T) {
-	generator.Generate(generator.DefaultMapParameters())
+	generator.Generate(generator.DefaultMapSetting())
 }
diff --git a/pkg/generator/map.go b/pkg/generator/map.go
new file mode 100644
index 0000000..9e098ee
--- /dev/null
+++ b/pkg/generator/map.go
@@ -0,0 +1,53 @@
+package generator
+
+import (
+	"fmt"
+)
+
+type Map struct {
+	Width       uint
+	Height      uint
+	HomePlanets []PlanetarySystem
+	FreePlanets []Planet
+	plotter     Plotter
+}
+
+type Coordinate struct {
+	X, Y float32
+}
+
+type Planet struct {
+	Position  Coordinate
+	Size      float32
+	Resources float32 // Сырьё
+}
+
+type PlanetarySystem struct {
+	HW Planet
+	DW []Planet
+}
+
+func NewMap(width, height, players uint) (*Map, error) {
+	p, err := NewPlotter(width, height, 1.0)
+	if err != nil {
+		return nil, fmt.Errorf("NewPlotter: %s", err)
+	}
+	return &Map{
+		Width:       width,
+		Height:      height,
+		HomePlanets: make([]PlanetarySystem, players),
+		plotter:     p,
+	}, nil
+}
+
+func (m *Map) AddPlanet(planet Planet) {
+	m.FreePlanets = append(m.FreePlanets, planet)
+}
+
+func (m Map) NewCoordinate(deadZoneRaduis float32) (Coordinate, error) {
+	if x, y, err := m.plotter.RandomFreePoint(deadZoneRaduis); err != nil {
+		return Coordinate{}, fmt.Errorf("NewCoordinate: RandomFreePoint: %s", err)
+	} else {
+		return Coordinate{X: x, Y: y}, nil
+	}
+}
diff --git a/pkg/generator/map_parameter.go b/pkg/generator/map_parameter.go
deleted file mode 100644
index 2e6d989..0000000
--- a/pkg/generator/map_parameter.go
+++ /dev/null
@@ -1,82 +0,0 @@
-package generator
-
-type MapParameter struct {
-	Players        uint
-	HW_Size        uint
-	HW_Resources   uint
-	HW_MinDistance uint
-	DW_Count       uint
-	DW_Size        uint
-	DW_Resources   uint
-	DW_MinDistance uint
-	DW_MaxDistance uint
-
-	GiantPlanets  UninhabitedPlanetParameters
-	BigPlanets    UninhabitedPlanetParameters
-	NormalPlanets UninhabitedPlanetParameters
-	RichPlanets   UninhabitedPlanetParameters
-	Asterioids    UninhabitedPlanetParameters
-}
-
-type UninhabitedPlanetParameters struct {
-	MinDistanceHW uint
-	MinSize       float64
-	MaxSize       float64
-	MinResource   float64
-	MaxResource   float64
-	Probability   float64
-}
-
-func DefaultMapParameters() MapParameter {
-	return MapParameter{
-		Players:        25,
-		HW_Size:        1000,
-		HW_Resources:   10,
-		HW_MinDistance: 30,
-		DW_Count:       2,
-		DW_Size:        500,
-		DW_Resources:   10,
-		DW_MinDistance: 5,
-		DW_MaxDistance: 15,
-		GiantPlanets: UninhabitedPlanetParameters{
-			MinDistanceHW: 20,
-			MinSize:       1500,
-			MaxSize:       2500,
-			MinResource:   0,
-			MaxResource:   3,
-			Probability:   0.06,
-		},
-		BigPlanets: UninhabitedPlanetParameters{
-			MinDistanceHW: 10,
-			MinSize:       1000,
-			MaxSize:       2000,
-			MinResource:   1,
-			MaxResource:   10,
-			Probability:   0.18,
-		},
-		NormalPlanets: UninhabitedPlanetParameters{
-			MinDistanceHW: 0,
-			MinSize:       0.001,
-			MaxSize:       1000,
-			MinResource:   0,
-			MaxResource:   10,
-			Probability:   0.5,
-		},
-		RichPlanets: UninhabitedPlanetParameters{
-			MinDistanceHW: 0,
-			MinSize:       0.001,
-			MaxSize:       500,
-			MinResource:   5,
-			MaxResource:   25,
-			Probability:   0.18,
-		},
-		Asterioids: UninhabitedPlanetParameters{
-			MinDistanceHW: 0,
-			MinSize:       0.001,
-			MaxSize:       10,
-			MinResource:   0,
-			MaxResource:   0,
-			Probability:   0.08,
-		},
-	}
-}
diff --git a/pkg/generator/plotter.go b/pkg/generator/plotter.go
new file mode 100644
index 0000000..478a4c4
--- /dev/null
+++ b/pkg/generator/plotter.go
@@ -0,0 +1,60 @@
+package generator
+
+import (
+	"errors"
+	"fmt"
+	"math/rand"
+
+	"github.com/iliadenisov/galaxy/pkg/bitmap"
+)
+
+type Plotter struct {
+	factor              float32
+	clearFn             func()
+	circleFn            func(x, y int, r float32)
+	freeCountFn         func() int
+	freeNumberToCoordFn func(int) (int, int)
+}
+
+func NewPlotter(width, height uint, factor float32) (Plotter, error) {
+	if factor > 1 || factor <= 0 {
+		return Plotter{}, fmt.Errorf("factor should be: 0 > F <= 1")
+	}
+	sectorsX := uint32(float32(width) / factor)
+	sectorsY := uint32(float32(height) / factor)
+	bm := bitmap.NewBitmap(sectorsX, sectorsY)
+	return Plotter{
+		factor:      factor,
+		clearFn:     bm.Clear,
+		circleFn:    func(x, y int, r float32) { bm.Circle(x, y, r, true) },
+		freeCountFn: bm.FreeCount,
+		freeNumberToCoordFn: func(n int) (x int, y int) {
+			x, y, err := bm.GetFreeN(n)
+			if err != nil {
+				panic(err)
+			}
+			return
+		},
+	}, nil
+}
+
+func (p Plotter) RandomFreePoint(deadZoneRaduis float32) (float32, float32, error) {
+	fsCount := p.freeCountFn()
+	if fsCount == 0 {
+		return 0, 0, errors.New("no more space for planets")
+	}
+	next := rand.Intn(fsCount)
+	x, y := p.freeNumberToCoordFn(next)
+	p.PlotDeadZone(x, y, deadZoneRaduis)
+	planetX := float32(x)*p.factor + rand.Float32()*p.factor // TODO: correct shift?
+	planetY := float32(y)*p.factor + rand.Float32()*p.factor
+	return planetX, planetY, nil
+}
+
+func (p Plotter) MarkDeadZone(x, y float32, radius float32) {
+	p.PlotDeadZone(int(x/p.factor), int(y/p.factor), radius)
+}
+
+func (p Plotter) PlotDeadZone(x, y int, radius float32) {
+	p.circleFn(x, y, radius/p.factor)
+}
diff --git a/pkg/generator/settings.go b/pkg/generator/settings.go
new file mode 100644
index 0000000..b9b6b3e
--- /dev/null
+++ b/pkg/generator/settings.go
@@ -0,0 +1,82 @@
+package generator
+
+type MapSetting struct {
+	Players       uint
+	HWSize        uint
+	HWResources   uint
+	HWMinDistance uint
+	DWCount       uint
+	DWSize        uint
+	DWResources   uint
+	DWMinDistance uint
+	DWMaxDistance uint
+
+	GiantPlanets  PlanetSetting
+	BigPlanets    PlanetSetting
+	NormalPlanets PlanetSetting
+	RichPlanets   PlanetSetting
+	Asterioids    PlanetSetting
+}
+
+type PlanetSetting struct {
+	MinDistanceHW uint
+	MinSize       float32
+	MaxSize       float32
+	MinResource   float32
+	MaxResource   float32
+	Probability   float32
+}
+
+func DefaultMapSetting() MapSetting {
+	return MapSetting{
+		Players:       25,
+		HWSize:        1000,
+		HWResources:   10,
+		HWMinDistance: 30,
+		DWCount:       2,
+		DWSize:        500,
+		DWResources:   10,
+		DWMinDistance: 5,
+		DWMaxDistance: 15,
+		GiantPlanets: PlanetSetting{
+			MinDistanceHW: 20,
+			MinSize:       1500,
+			MaxSize:       2500,
+			MinResource:   0,
+			MaxResource:   3,
+			Probability:   0.06,
+		},
+		BigPlanets: PlanetSetting{
+			MinDistanceHW: 10,
+			MinSize:       1000,
+			MaxSize:       2000,
+			MinResource:   1,
+			MaxResource:   10,
+			Probability:   0.18,
+		},
+		NormalPlanets: PlanetSetting{
+			MinDistanceHW: 0,
+			MinSize:       0.001,
+			MaxSize:       1000,
+			MinResource:   0,
+			MaxResource:   10,
+			Probability:   0.5,
+		},
+		RichPlanets: PlanetSetting{
+			MinDistanceHW: 0,
+			MinSize:       0.001,
+			MaxSize:       500,
+			MinResource:   5,
+			MaxResource:   25,
+			Probability:   0.18,
+		},
+		Asterioids: PlanetSetting{
+			MinDistanceHW: 0,
+			MinSize:       0.001,
+			MaxSize:       10,
+			MinResource:   0,
+			MaxResource:   0,
+			Probability:   0.08,
+		},
+	}
+}
diff --git a/pkg/server/server.go b/pkg/server/server.go
index 794d3cf..4aca619 100644
--- a/pkg/server/server.go
+++ b/pkg/server/server.go
@@ -16,7 +16,7 @@ func New(storage storage.Storage) Server {
 	return Server{storage: storage}
 }
 
-func (s Server) CreateGame(gameParam game.GameParameter, mapParam generator.MapParameter) (game.Game, error) {
-	_ = generator.Generate(mapParam)
+func (s Server) CreateGame(gameParam game.GameParameter, mapParam generator.MapSetting) (game.Game, error) {
+	_, _ = generator.Generate(mapParam)
 	return game.Game{}, errors.New("not yet implemented")
 }