diff --git a/build.gradle.kts b/build.gradle.kts
index 58e19c0..e303c6a 100644
--- a/build.gradle.kts
+++ b/build.gradle.kts
@@ -6,6 +6,8 @@ plugins {
     id("space.kscience.gradle.project")
 }
 
+val kmathVersion: String by extra("0.3.1-dev-10")
+
 allprojects {
     group = "center.sciprog"
     version = "0.2.2-dev-1"
diff --git a/demo/maps/src/jvmMain/kotlin/Main.kt b/demo/maps/src/jvmMain/kotlin/Main.kt
index 89be627..ba4da06 100644
--- a/demo/maps/src/jvmMain/kotlin/Main.kt
+++ b/demo/maps/src/jvmMain/kotlin/Main.kt
@@ -59,7 +59,7 @@ fun App() {
 
         val pointOne = 55.568548 to 37.568604
         val pointTwo = 55.929444 to 37.518434
-        val pointThree = 60.929444 to 37.518434
+//        val pointThree = 60.929444 to 37.518434
 
         MapView(
             mapTileProvider = mapTileProvider,
@@ -81,9 +81,15 @@ fun App() {
             val marker2 = rectangle(55.8 to 38.5, size = DpSize(10.dp, 10.dp)).color(Color.Magenta)
             val marker3 = rectangle(56.0 to 38.5, size = DpSize(10.dp, 10.dp)).color(Color.Magenta)
 
-            draggableLine(marker1, marker2).color(Color.Blue)
-            draggableLine(marker2, marker3).color(Color.Blue)
-            draggableLine(marker3, marker1).color(Color.Blue)
+            draggableLine(marker1, marker2, id = "line 1").color(Color.Red).onClick {
+                println("line 1 clicked")
+            }
+            draggableLine(marker2, marker3, id = "line 2").color(Color.DarkGray).onClick {
+                println("line 2 clicked")
+            }
+            draggableLine(marker3, marker1, id = "line 3").color(Color.Blue).onClick {
+                println("line 3 clicked")
+            }
 
             points(
                 points = listOf(
diff --git a/demo/scheme/src/jvmMain/kotlin/Main.kt b/demo/scheme/src/jvmMain/kotlin/Main.kt
index ec4acde..991d6e5 100644
--- a/demo/scheme/src/jvmMain/kotlin/Main.kt
+++ b/demo/scheme/src/jvmMain/kotlin/Main.kt
@@ -19,9 +19,9 @@ import center.sciprog.maps.svg.snapshot
 import kotlinx.coroutines.delay
 import kotlinx.coroutines.isActive
 import kotlinx.coroutines.launch
+import space.kscience.kmath.geometry.Angle
 import java.awt.Desktop
 import java.nio.file.Files
-import kotlin.math.PI
 
 @Composable
 @Preview
@@ -35,7 +35,7 @@ fun App() {
             text(410.52737 to 868.7676, "Shire").color(Color.Blue)
             circle(1132.0881 to 394.99127).color(Color.Red)
             text(1132.0881 to 394.99127, "Ordruin").color(Color.Red)
-            arc(center = 1132.0881 to 394.99127, radius = 20f, startAngle = 0f, 2 * PI.toFloat())
+            arc(center = 1132.0881 to 394.99127, radius = 20f, startAngle = Angle.zero, Angle.piTimes2)
 
             //circle(410.52737 to 868.7676, id = "hobbit")
 
diff --git a/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/GmcRectangle.kt b/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/GmcRectangle.kt
index e276a66..5401340 100644
--- a/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/GmcRectangle.kt
+++ b/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/GmcRectangle.kt
@@ -6,6 +6,8 @@ import center.sciprog.maps.features.Rectangle
 import space.kscience.kmath.geometry.Angle
 import space.kscience.kmath.geometry.abs
 
+internal fun Angle.isBetween(a: Angle, b: Angle) = this in a..b || this in b..a
+
 /**
  * A section of the map between two parallels and two meridians. The figure represents a square in a Mercator projection.
  * Params are two opposing "corners" of  quasi-square.
@@ -18,8 +20,7 @@ internal data class GmcRectangle(
 ) : Rectangle<Gmc> {
 
     override fun contains(point: Gmc): Boolean =
-        point.latitude in a.latitude..b.latitude
-                && point.longitude in a.longitude..b.longitude
+        point.latitude.isBetween(a.latitude, b.latitude) && point.longitude.isBetween(a.longitude, b.longitude)
 }
 
 public val Rectangle<Gmc>.center: GeodeticMapCoordinates
diff --git a/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/mapFeatures.kt b/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/mapFeatures.kt
index c28bda7..204e98b 100644
--- a/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/mapFeatures.kt
+++ b/maps-kt-compose/src/commonMain/kotlin/center/sciprog/maps/compose/mapFeatures.kt
@@ -12,7 +12,6 @@ import center.sciprog.maps.coordinates.Gmc
 import center.sciprog.maps.coordinates.GmcCurve
 import center.sciprog.maps.features.*
 import space.kscience.kmath.geometry.Angle
-import space.kscience.kmath.geometry.radians
 
 
 internal fun FeatureGroup<Gmc>.coordinatesOf(pair: Pair<Number, Number>) =
@@ -77,8 +76,8 @@ public fun FeatureGroup<Gmc>.arc(
     ArcFeature(
         space,
         oval = space.Rectangle(coordinatesOf(center), radius, radius),
-        startAngle = startAngle.radians.toFloat(),
-        arcLength = arcLength.radians.toFloat(),
+        startAngle = startAngle,
+        arcLength = arcLength,
     )
 )
 
diff --git a/maps-kt-core/build.gradle.kts b/maps-kt-core/build.gradle.kts
index 888c522..933d68e 100644
--- a/maps-kt-core/build.gradle.kts
+++ b/maps-kt-core/build.gradle.kts
@@ -3,7 +3,7 @@ plugins {
     `maven-publish`
 }
 
-val kmathVersion: String by rootProject.extra("0.3.1-dev-10")
+val kmathVersion: String by rootProject.extra
 
 kscience{
     useSerialization()
diff --git a/maps-kt-features/build.gradle.kts b/maps-kt-features/build.gradle.kts
index f5887cd..c0e7700 100644
--- a/maps-kt-features/build.gradle.kts
+++ b/maps-kt-features/build.gradle.kts
@@ -4,10 +4,13 @@ plugins {
     `maven-publish`
 }
 
+val kmathVersion: String by rootProject.extra
+
 kotlin {
     sourceSets {
         commonMain {
             dependencies {
+                api("space.kscience:kmath-trajectory:$kmathVersion")
                 api(compose.foundation)
             }
         }
diff --git a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/Feature.kt b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/Feature.kt
index 673d20d..2746609 100644
--- a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/Feature.kt
+++ b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/Feature.kt
@@ -16,6 +16,7 @@ import androidx.compose.ui.unit.DpSize
 import androidx.compose.ui.unit.dp
 import center.sciprog.attributes.Attributes
 import center.sciprog.attributes.NameAttribute
+import space.kscience.kmath.geometry.Angle
 
 public typealias FloatRange = ClosedFloatingPointRange<Float>
 
@@ -185,7 +186,7 @@ public data class LineFeature<T : Any>(
     override fun getBoundingBox(zoom: Float): Rectangle<T> =
         space.Rectangle(a, b)
 
-    private val clickRadius get() = attributes[ClickRadius] ?: 20f
+    private val clickRadius get() = attributes[ClickRadius] ?: 10f
 
     override fun contains(viewPoint: ViewPoint<T>): Boolean = with(space) {
         viewPoint.focus in getBoundingBox(viewPoint.zoom) && viewPoint.focus.distanceToLine(
@@ -206,8 +207,8 @@ public data class LineFeature<T : Any>(
 public data class ArcFeature<T : Any>(
     override val space: CoordinateSpace<T>,
     public val oval: Rectangle<T>,
-    public val startAngle: Float,
-    public val arcLength: Float,
+    public val startAngle: Angle,
+    public val arcLength: Angle,
     override val attributes: Attributes = Attributes.EMPTY,
 ) : DraggableFeature<T> {
     override fun getBoundingBox(zoom: Float): Rectangle<T> = oval
diff --git a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/FeatureGroup.kt b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/FeatureGroup.kt
index e09f1f3..b7f07bc 100644
--- a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/FeatureGroup.kt
+++ b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/FeatureGroup.kt
@@ -12,6 +12,7 @@ import androidx.compose.ui.unit.Dp
 import androidx.compose.ui.unit.DpSize
 import androidx.compose.ui.unit.dp
 import center.sciprog.attributes.*
+import space.kscience.kmath.geometry.Angle
 
 //@JvmInline
 //public value class FeatureId<out F : Feature<*>>(public val id: String)
@@ -188,8 +189,8 @@ public fun <T : Any> FeatureGroup<T>.line(
 
 public fun <T : Any> FeatureGroup<T>.arc(
     oval: Rectangle<T>,
-    startAngle: Float,
-    arcLength: Float,
+    startAngle: Angle,
+    arcLength: Angle,
     id: String? = null,
 ): FeatureRef<T, ArcFeature<T>> = feature(
     id,
diff --git a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/compositeFeatures.kt b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/compositeFeatures.kt
index 7a30a74..8177114 100644
--- a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/compositeFeatures.kt
+++ b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/compositeFeatures.kt
@@ -11,17 +11,18 @@ public fun <T : Any> FeatureGroup<T>.draggableLine(
     var lineId: FeatureRef<T, LineFeature<T>>? = null
 
     fun drawLine(): FeatureRef<T, LineFeature<T>> {
-        //save attributes before update
-        val attributes: Attributes? = lineId?.attributes
-        val currentId = line(
-            aId.resolve().center,
-            bId.resolve().center,
-            lineId?.id ?: id
+        val currentId = feature(
+            lineId?.id ?: id,
+            LineFeature(
+                space,
+                aId.resolve().center,
+                bId.resolve().center,
+                Attributes {
+                    ZAttribute(-10f)
+                    lineId?.attributes?.let { from(it) }
+                }
+            )
         )
-        currentId.modifyAttributes {
-            ZAttribute(-10f)
-            if (attributes != null) from(attributes)
-        }
         lineId = currentId
         return currentId
     }
diff --git a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/mapFeatureAttributes.kt b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/mapFeatureAttributes.kt
index 0284b67..e57d86f 100644
--- a/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/mapFeatureAttributes.kt
+++ b/maps-kt-features/src/commonMain/kotlin/center/sciprog/maps/features/mapFeatureAttributes.kt
@@ -57,8 +57,6 @@ public fun <T : Any, F : Feature<T>, V>  FeatureRef<T, F>.modifyAttribute(key: A
  * Add drag to this feature
  *
  * @param constraint optional drag constraint
- *
- * TODO use context receiver for that
  */
 @Suppress("UNCHECKED_CAST")
 public fun <T: Any, F : DraggableFeature<T>> FeatureRef<T, F>.draggable(
diff --git a/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/compose/mapControls.kt b/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/compose/mapControls.kt
index 41718c4..bc7bf76 100644
--- a/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/compose/mapControls.kt
+++ b/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/compose/mapControls.kt
@@ -1,6 +1,5 @@
 package center.sciprog.maps.compose
 
-import androidx.compose.foundation.ExperimentalFoundationApi
 import androidx.compose.foundation.gestures.drag
 import androidx.compose.ui.Modifier
 import androidx.compose.ui.geometry.Offset
@@ -17,7 +16,6 @@ import kotlin.math.min
  * Create a modifier for Map/Scheme canvas controls on desktop
  * @param features a collection of features to be rendered in descending [ZAttribute] order
  */
-@OptIn(ExperimentalFoundationApi::class)
 public fun <T : Any> Modifier.mapControls(
     state: CoordinateViewScope<T>,
     features: FeatureGroup<T>,
@@ -55,7 +53,7 @@ public fun <T : Any> Modifier.mapControls(
                                     point
                                 )
                                 features.forEachWithAttributeUntil(ClickListenerAttribute) { _, feature, listeners ->
-                                    if (point in feature as DomainFeature) {
+                                    if (point in (feature as DomainFeature)) {
                                         listeners.forEach { it.handle(event, point) }
                                         false
                                     } else {
diff --git a/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/features/drawFeature.kt b/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/features/drawFeature.kt
index c75e2db..ea6d2c6 100644
--- a/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/features/drawFeature.kt
+++ b/maps-kt-features/src/jvmMain/kotlin/center/sciprog/maps/features/drawFeature.kt
@@ -14,6 +14,7 @@ import androidx.compose.ui.graphics.toArgb
 import center.sciprog.attributes.plus
 import org.jetbrains.skia.Font
 import org.jetbrains.skia.Paint
+import space.kscience.kmath.geometry.degrees
 import kotlin.math.PI
 
 
@@ -56,8 +57,8 @@ public fun <T : Any> DrawScope.drawFeature(
 
             drawArc(
                 color = color,
-                startAngle = feature.startAngle / PI.toFloat() * 180f,
-                sweepAngle = feature.arcLength / PI.toFloat() * 180f,
+                startAngle = (feature.startAngle.degrees / PI * 180).toFloat(),
+                sweepAngle = (feature.arcLength.degrees / PI * 180).toFloat(),
                 useCenter = false,
                 topLeft = dpRect.topLeft,
                 size = size,
diff --git a/maps-kt-scheme/src/commonMain/kotlin/center/sciprog/maps/scheme/schemeFeatures.kt b/maps-kt-scheme/src/commonMain/kotlin/center/sciprog/maps/scheme/schemeFeatures.kt
index 2f0af99..cbb547d 100644
--- a/maps-kt-scheme/src/commonMain/kotlin/center/sciprog/maps/scheme/schemeFeatures.kt
+++ b/maps-kt-scheme/src/commonMain/kotlin/center/sciprog/maps/scheme/schemeFeatures.kt
@@ -9,6 +9,7 @@ import androidx.compose.ui.unit.DpSize
 import androidx.compose.ui.unit.dp
 import center.sciprog.attributes.Attributes
 import center.sciprog.maps.features.*
+import space.kscience.kmath.geometry.Angle
 
 internal fun Pair<Number, Number>.toCoordinates(): XY = XY(first.toFloat(), second.toFloat())
 
@@ -56,8 +57,8 @@ fun FeatureGroup<XY>.line(
 public fun FeatureGroup<XY>.arc(
     center: Pair<Double, Double>,
     radius: Float,
-    startAngle: Float,
-    arcLength: Float,
+    startAngle: Angle,
+    arcLength: Angle,
     id: String? = null,
 ): FeatureRef<XY, ArcFeature<XY>> = arc(
     oval = XYCoordinateSpace.Rectangle(center.toCoordinates(), radius, radius),
diff --git a/maps-kt-scheme/src/jvmMain/kotlin/center/sciprog/maps/svg/exportToSvg.kt b/maps-kt-scheme/src/jvmMain/kotlin/center/sciprog/maps/svg/exportToSvg.kt
index 54d041f..d1b9119 100644
--- a/maps-kt-scheme/src/jvmMain/kotlin/center/sciprog/maps/svg/exportToSvg.kt
+++ b/maps-kt-scheme/src/jvmMain/kotlin/center/sciprog/maps/svg/exportToSvg.kt
@@ -12,8 +12,8 @@ import center.sciprog.maps.features.*
 import center.sciprog.maps.scheme.*
 import org.jfree.svg.SVGGraphics2D
 import org.jfree.svg.SVGUtils
+import space.kscience.kmath.geometry.degrees
 import java.awt.Font.PLAIN
-import kotlin.math.PI
 import kotlin.math.abs
 
 
@@ -23,7 +23,7 @@ class FeatureStateSnapshot<T : Any>(
 )
 
 @Composable
-fun <T: Any> FeatureGroup<T>.snapshot(): FeatureStateSnapshot<T> = FeatureStateSnapshot(
+fun <T : Any> FeatureGroup<T>.snapshot(): FeatureStateSnapshot<T> = FeatureStateSnapshot(
     featureMap,
     features.filterIsInstance<PainterFeature<T>>().associateWith { it.getPainter() }
 )
@@ -44,7 +44,7 @@ fun FeatureStateSnapshot<XY>.generateSvg(
     fun SvgDrawScope.drawFeature(scale: Float, feature: Feature<XY>) {
 
         val color = feature.color ?: Color.Red
-        val alpha = feature.attributes[AlphaAttribute]?:1f
+        val alpha = feature.attributes[AlphaAttribute] ?: 1f
 
         when (feature) {
             is ScalableImageFeature -> {
@@ -66,10 +66,16 @@ fun FeatureStateSnapshot<XY>.generateSvg(
             is CircleFeature -> drawCircle(
                 color,
                 feature.size.toPx(),
-                center = feature.center.toOffset()
+                center = feature.center.toOffset(),
+                alpha = alpha
             )
 
-            is LineFeature -> drawLine(color, feature.a.toOffset(), feature.b.toOffset())
+            is LineFeature -> drawLine(
+                color,
+                feature.a.toOffset(),
+                feature.b.toOffset(),
+                alpha = alpha
+            )
 
             is ArcFeature -> {
                 val topLeft = feature.oval.leftTop.toOffset()
@@ -79,12 +85,13 @@ fun FeatureStateSnapshot<XY>.generateSvg(
 
                 drawArc(
                     color = color,
-                    startAngle = (feature.startAngle * 180 / PI).toFloat(),
-                    sweepAngle = (feature.arcLength * 180 / PI).toFloat(),
+                    startAngle = feature.startAngle.degrees.toFloat(),
+                    sweepAngle = feature.arcLength.degrees.toFloat(),
                     useCenter = false,
                     topLeft = topLeft,
                     size = size,
-                    style = Stroke()
+                    style = Stroke(),
+                    alpha = alpha
                 )
             }
 
@@ -95,12 +102,12 @@ fun FeatureStateSnapshot<XY>.generateSvg(
                 val imageSize = feature.size.toSize()
                 translate(offset.x - imageSize.width / 2, offset.y - imageSize.height / 2) {
                     with(painterCache[feature]!!) {
-                        draw(imageSize)
+                        draw(imageSize, alpha = alpha)
                     }
                 }
             }
 
-            is TextFeature -> drawIntoCanvas { canvas ->
+            is TextFeature -> drawIntoCanvas { _ ->
                 val offset = feature.position.toOffset()
                 drawText(
                     feature.text,