diff --git a/index.css b/index.css
index 1cb69877..58e92533 100644
--- a/index.css
+++ b/index.css
@@ -1303,11 +1303,6 @@ div.slider .ui-slider-handle {
   color: white;
 }
 
-#brushPower,
-#brushRadius {
-  width: 12em;
-}
-
 #rescaleHigher,
 #rescaleLower,
 #rescaleModifier {
diff --git a/index.html b/index.html
index 946c53d1..ae7345ee 100644
--- a/index.html
+++ b/index.html
@@ -108,7 +108,7 @@
       }
     </style>
 
-    <link rel="preload" href="index.css" as="style" onload="this.onload=null; this.rel='stylesheet'" />
+    <link rel="preload" href="index.css?v=1.88.00" as="style" onload="this.onload=null; this.rel='stylesheet'" />
     <link rel="preload" href="icons.css" as="style" onload="this.onload=null; this.rel='stylesheet'" />
     <link rel="preload" href="libs/jquery-ui.css" as="style" onload="this.onload=null; this.rel='stylesheet'" />
   </head>
@@ -3836,6 +3836,12 @@
               <path d="m15,63 l15,-13 15,20 15,-20 15,19 15,-14" fill="none" stroke="#000" stroke-width="5" />
             </svg>
           </button>
+
+          <button id="brushLine" data-tip="Line: select two points to change heights along the line">
+            <svg viewBox="0 -5 100 100" height="1em" width="1.6em">
+              <path d="M0 90 L100 10" fill="none" stroke="#000" stroke-width="7"></path>
+            </svg>
+          </button>
         </div>
 
         <div id="brushesSliders" style="display: none">
@@ -3848,6 +3854,7 @@
               min="1"
               max="99"
               value="25"
+              style="width: 13em"
             />
             <input
               id="brushRadiusNumber"
@@ -3869,6 +3876,7 @@
               min="1"
               max="10"
               value="5"
+              style="width: 13em"
             />
             <input
               id="brushPowerNumber"
@@ -3882,6 +3890,30 @@
           </div>
         </div>
 
+        <div id="lineSlider" style="display: none">
+          <div data-tip="Set change power">
+            <div style="width: 3.2em; display: inline-block"><i>Power:</i></div>
+            <input
+              id="linePower"
+              oninput="tip('Line power: '+this.value); linePowerNumber.value = this.value"
+              type="range"
+              min="-100"
+              max="100"
+              value="30"
+              style="width: 13em"
+            />
+            <input
+              id="linePowerNumber"
+              oninput="tip('Line power: '+this.value); linePower.value = this.value"
+              type="number"
+              min="-100"
+              max="100"
+              value="30"
+              style="border: 1px solid #d4d4d4"
+            />
+          </div>
+        </div>
+
         <div
           data-tip="Allow brush to change only land cells and hence restrict the coastline modification"
           style="margin-bottom: 0.6em"
@@ -7796,7 +7828,7 @@
     <script src="utils/nodeUtils.js"></script>
     <script src="utils/numberUtils.js"></script>
     <script src="utils/polyfills.js"></script>
-    <script src="utils/probabilityUtils.js"></script>
+    <script src="utils/probabilityUtils.js?v=1.88.00"></script>
     <script src="utils/stringUtils.js"></script>
     <script src="utils/languageUtils.js"></script>
     <script src="utils/unitUtils.js?v=1.87.00"></script>
@@ -7804,7 +7836,7 @@
     <script src="modules/voronoi.js"></script>
     <script src="config/heightmap-templates.js"></script>
     <script src="config/precreated-heightmaps.js"></script>
-    <script src="modules/heightmap-generator.js"></script>
+    <script src="modules/heightmap-generator.js?v=1.88.00"></script>
     <script src="modules/ocean-layers.js?v=1.87.15"></script>
     <script src="modules/river-generator.js"></script>
     <script src="modules/lakes.js"></script>
@@ -7834,7 +7866,7 @@
     <script defer src="modules/ui/editors.js?v=1.87.07"></script>
     <script defer src="modules/ui/tools.js?v=1.87.03"></script>
     <script defer src="modules/ui/world-configurator.js"></script>
-    <script defer src="modules/ui/heightmap-editor.js?v=1.87.10"></script>
+    <script defer src="modules/ui/heightmap-editor.js?v=1.88.00"></script>
     <script defer src="modules/ui/provinces-editor.js"></script>
     <script defer src="modules/ui/biomes-editor.js"></script>
     <script defer src="modules/ui/namesbase-editor.js?v=1.87.10"></script>
@@ -7864,7 +7896,7 @@
     <script defer src="modules/ui/markers-editor.js"></script>
     <script defer src="modules/ui/3d.js"></script>
     <script defer src="modules/ui/submap.js"></script>
-    <script defer src="modules/ui/hotkeys.js?v=1.87.00"></script>
+    <script defer src="modules/ui/hotkeys.js?v=1.88.00"></script>
     <script defer src="modules/coa-renderer.js?v=1.87.08"></script>
     <script defer src="libs/rgbquant.min.js"></script>
     <script defer src="libs/jquery.ui.touch-punch.min.js"></script>
diff --git a/modules/heightmap-generator.js b/modules/heightmap-generator.js
index 66696953..5a69337e 100644
--- a/modules/heightmap-generator.js
+++ b/modules/heightmap-generator.js
@@ -8,7 +8,7 @@ window.HeightmapGenerator = (function () {
 
   const setGraph = graph => {
     const {cellsDesired, cells, points} = graph;
-    heights = cells.h || createTypedArray({maxValue: 100, length: points.length});
+    heights = cells.h ? Uint8Array.from(cells.h) : createTypedArray({maxValue: 100, length: points.length});
     blobPower = getBlobPower(cellsDesired);
     linePower = getLinePower(cellsDesired);
     grid = graph;
@@ -198,7 +198,8 @@ window.HeightmapGenerator = (function () {
     }
   };
 
-  const addRange = (count, height, rangeX, rangeY) => {
+  // fromCell, toCell are options cell ids
+  const addRange = (count, height, rangeX, rangeY, startCell, endCell) => {
     count = getNumberInRange(count);
     while (count > 0) {
       addOneRange();
@@ -209,23 +210,27 @@ window.HeightmapGenerator = (function () {
       const used = new Uint8Array(heights.length);
       let h = lim(getNumberInRange(height));
 
-      // find start and end points
-      const startX = getPointInRange(rangeX, graphWidth);
-      const startY = getPointInRange(rangeY, graphHeight);
+      if (rangeX && rangeY) {
+        // find start and end points
+        const startX = getPointInRange(rangeX, graphWidth);
+        const startY = getPointInRange(rangeY, graphHeight);
 
-      let dist = 0,
-        limit = 0,
-        endX,
-        endY;
-      do {
-        endX = Math.random() * graphWidth * 0.8 + graphWidth * 0.1;
-        endY = Math.random() * graphHeight * 0.7 + graphHeight * 0.15;
-        dist = Math.abs(endY - startY) + Math.abs(endX - startX);
-        limit++;
-      } while ((dist < graphWidth / 8 || dist > graphWidth / 3) && limit < 50);
+        let dist = 0,
+          limit = 0,
+          endX,
+          endY;
+
+        do {
+          endX = Math.random() * graphWidth * 0.8 + graphWidth * 0.1;
+          endY = Math.random() * graphHeight * 0.7 + graphHeight * 0.15;
+          dist = Math.abs(endY - startY) + Math.abs(endX - startX);
+          limit++;
+        } while ((dist < graphWidth / 8 || dist > graphWidth / 3) && limit < 50);
+
+        startCell = findGridCell(startX, startY, grid);
+        endCell = findGridCell(endX, endY, grid);
+      }
 
-      const startCell = findGridCell(startX, startY, grid);
-      const endCell = findGridCell(endX, endY, grid);
       let range = getRange(startCell, endCell);
 
       // get main ridge
@@ -286,7 +291,7 @@ window.HeightmapGenerator = (function () {
     }
   };
 
-  const addTrough = (count, height, rangeX, rangeY) => {
+  const addTrough = (count, height, rangeX, rangeY, startCell, endCell) => {
     count = getNumberInRange(count);
     while (count > 0) {
       addOneTrough();
@@ -297,30 +302,33 @@ window.HeightmapGenerator = (function () {
       const used = new Uint8Array(heights.length);
       let h = lim(getNumberInRange(height));
 
-      // find start and end points
-      let limit = 0,
-        startX,
-        startY,
-        start,
-        dist = 0,
-        endX,
-        endY;
-      do {
-        startX = getPointInRange(rangeX, graphWidth);
-        startY = getPointInRange(rangeY, graphHeight);
-        start = findGridCell(startX, startY, grid);
-        limit++;
-      } while (heights[start] < 20 && limit < 50);
+      if (rangeX && rangeY) {
+        // find start and end points
+        let limit = 0,
+          startX,
+          startY,
+          dist = 0,
+          endX,
+          endY;
+        do {
+          startX = getPointInRange(rangeX, graphWidth);
+          startY = getPointInRange(rangeY, graphHeight);
+          startCell = findGridCell(startX, startY, grid);
+          limit++;
+        } while (heights[startCell] < 20 && limit < 50);
 
-      limit = 0;
-      do {
-        endX = Math.random() * graphWidth * 0.8 + graphWidth * 0.1;
-        endY = Math.random() * graphHeight * 0.7 + graphHeight * 0.15;
-        dist = Math.abs(endY - startY) + Math.abs(endX - startX);
-        limit++;
-      } while ((dist < graphWidth / 8 || dist > graphWidth / 2) && limit < 50);
+        limit = 0;
+        do {
+          endX = Math.random() * graphWidth * 0.8 + graphWidth * 0.1;
+          endY = Math.random() * graphHeight * 0.7 + graphHeight * 0.15;
+          dist = Math.abs(endY - startY) + Math.abs(endX - startX);
+          limit++;
+        } while ((dist < graphWidth / 8 || dist > graphWidth / 2) && limit < 50);
 
-      let range = getRange(start, findGridCell(endX, endY, grid));
+        endCell = findGridCell(endX, endY, grid);
+      }
+
+      let range = getRange(startCell, endCell);
 
       // get main ridge
       function getRange(cur, end) {
@@ -388,8 +396,12 @@ window.HeightmapGenerator = (function () {
     const vert = direction === "vertical";
     const startX = vert ? Math.floor(Math.random() * graphWidth * 0.4 + graphWidth * 0.3) : 5;
     const startY = vert ? 5 : Math.floor(Math.random() * graphHeight * 0.4 + graphHeight * 0.3);
-    const endX = vert ? Math.floor(graphWidth - startX - graphWidth * 0.1 + Math.random() * graphWidth * 0.2) : graphWidth - 5;
-    const endY = vert ? graphHeight - 5 : Math.floor(graphHeight - startY - graphHeight * 0.1 + Math.random() * graphHeight * 0.2);
+    const endX = vert
+      ? Math.floor(graphWidth - startX - graphWidth * 0.1 + Math.random() * graphWidth * 0.2)
+      : graphWidth - 5;
+    const endY = vert
+      ? graphHeight - 5
+      : Math.floor(graphHeight - startY - graphHeight * 0.1 + Math.random() * graphHeight * 0.2);
 
     const start = findGridCell(startX, startY, grid);
     const end = findGridCell(endX, endY, grid);
diff --git a/modules/ui/heightmap-editor.js b/modules/ui/heightmap-editor.js
index f72afd13..7f83354a 100644
--- a/modules/ui/heightmap-editor.js
+++ b/modules/ui/heightmap-editor.js
@@ -130,6 +130,12 @@ function editHeightmap(options) {
     // move radius circle if drag mode is active
     const pressed = byId("brushesButtons").querySelector("button.pressed");
     if (!pressed) return;
+
+    if (pressed.id === "brushLine") {
+      debug.select("line").attr("x2", x).attr("y2", y);
+      return;
+    }
+
     moveCircle(x, y, brushRadius.valueAsNumber, "#333");
   }
 
@@ -181,7 +187,6 @@ function editHeightmap(options) {
     else if (mode === "risk") restoreRiskedData();
 
     // restore initial layers
-    //viewbox.select("#heights").remove();
     byId("heights").remove();
     turnButtonOff("toggleHeight");
     document
@@ -494,10 +499,8 @@ function editHeightmap(options) {
 
     selection.forEach(function (i) {
       let cell = viewbox.select("#heights").select("#cell" + i);
-      if (!ocean && grid.cells.h[i] < 20) {
-        cell.remove();
-        return;
-      }
+      if (!ocean && grid.cells.h[i] < 20) return cell.remove();
+
       if (!cell.size())
         cell = viewbox
           .select("#heights")
@@ -594,24 +597,81 @@ function editHeightmap(options) {
 
     function exitBrushMode() {
       const pressed = document.querySelector("#brushesButtons > button.pressed");
-      if (!pressed) return;
-      pressed.classList.remove("pressed");
+      if (pressed) pressed.classList.remove("pressed");
 
-      viewbox.style("cursor", "default").on(".drag", null);
+      viewbox.style("cursor", "default").on(".drag", null).on("click", clicked);
+      debug.selectAll(".lineCircle").remove();
       removeCircle();
+
       byId("brushesSliders").style.display = "none";
+      byId("lineSlider").style.display = "none";
     }
 
     const dragBrushThrottled = throttle(dragBrush, 100);
-    function toggleBrushMode(e) {
-      if (e.target.classList.contains("pressed")) {
+
+    function toggleBrushMode(event) {
+      if (event.target.classList.contains("pressed")) {
         exitBrushMode();
         return;
       }
+
       exitBrushMode();
-      byId("brushesSliders").style.display = "block";
-      e.target.classList.add("pressed");
-      viewbox.style("cursor", "crosshair").call(d3.drag().on("start", dragBrushThrottled));
+      event.target.classList.add("pressed");
+
+      if (event.target.id === "brushLine") {
+        byId("lineSlider").style.display = "block";
+        viewbox.style("cursor", "crosshair").on("click", placeLinearFeature);
+      } else {
+        byId("brushesSliders").style.display = "block";
+        viewbox.style("cursor", "crosshair").call(d3.drag().on("start", dragBrushThrottled));
+      }
+    }
+
+    function placeLinearFeature() {
+      const [x, y] = d3.mouse(this);
+      const toCell = findGridCell(x, y, grid);
+
+      const lineCircle = debug.selectAll(".lineCircle");
+      if (!lineCircle.size()) {
+        // first click: add 1st control point
+        debug.append("line").attr("id", "brushCircle").attr("x1", x).attr("y1", y).attr("x2", x).attr("y2", y);
+
+        debug
+          .append("circle")
+          .attr("data-cell", toCell)
+          .attr("class", "lineCircle")
+          .attr("r", 6)
+          .attr("cx", x)
+          .attr("cy", y)
+          .attr("fill", "yellow")
+          .attr("stroke", "#333")
+          .attr("stroke-width", 2);
+        return;
+      }
+
+      // second click: execute operation and remove control points
+      const fromCell = +lineCircle.attr("data-cell");
+      debug.selectAll("*").remove();
+
+      const power = byId("linePower").valueAsNumber;
+      if (power === 0) return tip("Power should not be zero", false, "error");
+
+      const heights = grid.cells.h;
+      const operation = power > 0 ? HeightmapGenerator.addRange : HeightmapGenerator.addTrough;
+      HeightmapGenerator.setGraph(grid);
+      operation("1", String(Math.abs(power)), null, null, fromCell, toCell);
+      const changedHeights = HeightmapGenerator.getHeights();
+
+      let selection = [];
+      for (let i = 0; i < heights.length; i++) {
+        if (changedHeights[i] === heights[i]) continue;
+        if (changeOnlyLand.checked && heights[i] < 20) continue;
+        heights[i] = changedHeights[i];
+        selection.push(i);
+      }
+
+      mockHeightmapSelection(selection);
+      updateHistory();
     }
 
     function dragBrush() {
@@ -632,37 +692,44 @@ function editHeightmap(options) {
       d3.event.on("end", updateHeightmap);
     }
 
-    function changeHeightForSelection(s, start) {
+    function changeHeightForSelection(selection, start) {
       const power = brushPower.valueAsNumber;
+
       const interpolate = d3.interpolateRound(power, 1);
       const land = changeOnlyLand.checked;
       const lim = v => minmax(v, land ? 20 : 0, 100);
-      const h = grid.cells.h;
+      const heights = grid.cells.h;
 
       const brush = document.querySelector("#brushesButtons > button.pressed").id;
-      if (brush === "brushRaise") s.forEach(i => (h[i] = h[i] < 20 ? 20 : lim(h[i] + power)));
+      if (brush === "brushRaise") selection.forEach(i => (heights[i] = heights[i] < 20 ? 20 : lim(heights[i] + power)));
       else if (brush === "brushElevate")
-        s.forEach((i, d) => (h[i] = lim(h[i] + interpolate(d / Math.max(s.length - 1, 1)))));
-      else if (brush === "brushLower") s.forEach(i => (h[i] = lim(h[i] - power)));
+        selection.forEach(
+          (i, d) => (heights[i] = lim(heights[i] + interpolate(d / Math.max(selection.length - 1, 1))))
+        );
+      else if (brush === "brushLower") selection.forEach(i => (heights[i] = lim(heights[i] - power)));
       else if (brush === "brushDepress")
-        s.forEach((i, d) => (h[i] = lim(h[i] - interpolate(d / Math.max(s.length - 1, 1)))));
-      else if (brush === "brushAlign") s.forEach(i => (h[i] = lim(h[start])));
+        selection.forEach(
+          (i, d) => (heights[i] = lim(heights[i] - interpolate(d / Math.max(selection.length - 1, 1))))
+        );
+      else if (brush === "brushAlign") selection.forEach(i => (heights[i] = lim(heights[start])));
       else if (brush === "brushSmooth")
-        s.forEach(
+        selection.forEach(
           i =>
-            (h[i] = rn(
-              (d3.mean(grid.cells.c[i].filter(i => (land ? h[i] >= 20 : 1)).map(c => h[c])) +
-                h[i] * (10 - power) +
+            (heights[i] = rn(
+              (d3.mean(grid.cells.c[i].filter(i => (land ? heights[i] >= 20 : 1)).map(c => heights[c])) +
+                heights[i] * (10 - power) +
                 0.6) /
                 (11 - power),
               1
             ))
         );
       else if (brush === "brushDisrupt")
-        s.forEach(i => (h[i] = h[i] < 15 ? h[i] : lim(h[i] + power / 1.6 - Math.random() * power)));
+        selection.forEach(
+          i => (heights[i] = heights[i] < 15 ? heights[i] : lim(heights[i] + power / 1.6 - Math.random() * power))
+        );
 
-      mockHeightmapSelection(s);
-      // updateHistory(); uncomment to update history every step
+      mockHeightmapSelection(selection);
+      // updateHistory(); uncomment to update history on every step
     }
 
     function changeOnlyLandClick(e) {
diff --git a/modules/ui/hotkeys.js b/modules/ui/hotkeys.js
index d8fcaaf8..f7443469 100644
--- a/modules/ui/hotkeys.js
+++ b/modules/ui/hotkeys.js
@@ -89,13 +89,13 @@ function handleKeyup(event) {
   else if (code === "KeyI") toggleIcons();
   else if (code === "KeyM") toggleMilitary();
   else if (code === "KeyK") toggleMarkers();
-  else if (code === "Equal") toggleRulers();
+  else if (code === "Equal" && !customization) toggleRulers();
   else if (code === "Slash") toggleScaleBar();
   else if (code === "ArrowLeft") zoom.translateBy(svg, 10, 0);
   else if (code === "ArrowRight") zoom.translateBy(svg, -10, 0);
   else if (code === "ArrowUp") zoom.translateBy(svg, 0, 10);
   else if (code === "ArrowDown") zoom.translateBy(svg, 0, -10);
-  else if (key === "+" || key === "-") pressNumpadSign(key);
+  else if (key === "+" || key === "-" || key === "=") handleSizeChange(key);
   else if (key === "0") resetZoom(1000);
   else if (key === "1") zoom.scaleTo(svg, 1);
   else if (key === "2") zoom.scaleTo(svg, 2);
@@ -117,11 +117,12 @@ function allowHotkeys() {
   return true;
 }
 
-function pressNumpadSign(key) {
-  const change = key === "+" ? 1 : -1;
+// "+", "-" and "=" keys on numpad. "=" is for "+" on Mac
+function handleSizeChange(key) {
   let brush = null;
 
   if (document.getElementById("brushRadius")?.offsetParent) brush = document.getElementById("brushRadius");
+  else if (document.getElementById("linePower")?.offsetParent) brush = document.getElementById("linePower");
   else if (document.getElementById("biomesManuallyBrush")?.offsetParent)
     brush = document.getElementById("biomesManuallyBrush");
   else if (document.getElementById("statesManuallyBrush")?.offsetParent)
@@ -135,6 +136,7 @@ function pressNumpadSign(key) {
     brush = document.getElementById("religionsManuallyBrush");
 
   if (brush) {
+    const change = key === "-" ? -5 : 5;
     const value = minmax(+brush.value + change, +brush.min, +brush.max);
     brush.value = document.getElementById(brush.id + "Number").value = value;
     return;
diff --git a/utils/probabilityUtils.js b/utils/probabilityUtils.js
index 7759e330..b0234251 100644
--- a/utils/probabilityUtils.js
+++ b/utils/probabilityUtils.js
@@ -56,7 +56,7 @@ function biased(min, max, ex) {
 // get number from string in format "1-3" or "2" or "0.5"
 function getNumberInRange(r) {
   if (typeof r !== "string") {
-    ERROR && console.error("The value should be a string", r);
+    ERROR && console.error("Range value should be a string", r);
     return 0;
   }
   if (!isNaN(+r)) return ~~r + +P(r - ~~r);
diff --git a/versioning.js b/versioning.js
index ea45eff7..6dac46df 100644
--- a/versioning.js
+++ b/versioning.js
@@ -1,7 +1,7 @@
 "use strict";
 
 // version and caching control
-const version = "1.87.15"; // generator version, update each time
+const version = "1.88.00"; // generator version, update each time
 
 {
   document.title += " v" + version;
@@ -28,6 +28,7 @@ const version = "1.87.15"; // generator version, update each time
 
       <ul>
         <strong>Latest changes:</strong>
+        <li>Heightmap brushes: linear edit option</li>
         <li>Data Charts screen</li>
         <li>Сultures and religions can have multiple parents in hierarchy tree</li>
         <li>Heightmap selection screen</li>