diff --git a/src/main/java/org/dynmap/hdmap/IsoHDPerspective.java b/src/main/java/org/dynmap/hdmap/IsoHDPerspective.java
index a2d24851..771bc918 100644
--- a/src/main/java/org/dynmap/hdmap/IsoHDPerspective.java
+++ b/src/main/java/org/dynmap/hdmap/IsoHDPerspective.java
@@ -1019,11 +1019,13 @@ public class IsoHDPerspective implements HDPerspective {
         Vector3D corners[] = new Vector3D[8];
         int[] chunk_x = new int[8];
         int[] chunk_z = new int[8];
+        int dx = -1, dy = -1;
         for(int x = t.tx, idx = 0; x <= (t.tx+1); x++) {
+            dy = -1;
             for(int y = t.ty; y <= (t.ty+1); y++) {
                 for(int z = 0; z <= 1; z++) {
                     corners[idx] = new Vector3D();
-                    corners[idx].x = x*tileWidth; corners[idx].y = y*tileHeight; corners[idx].z = z*128;
+                    corners[idx].x = x*tileWidth + dx; corners[idx].y = y*tileHeight + dy; corners[idx].z = z*128;
                     map_to_world.transform(corners[idx]);
                     /* Compute chunk coordinates of corner */
                     chunk_x[idx] = (int)Math.floor(corners[idx].x / 16);
@@ -1035,7 +1037,9 @@ public class IsoHDPerspective implements HDPerspective {
                     if(max_chunk_z < chunk_z[idx]) max_chunk_z = chunk_z[idx];
                     idx++;
                 }
+                dy = 1;
             }
+            dx = 1;
         }
         /* Make rectangles of X-Z projection of each side of the tile volume, 0 = top, 1 = bottom, 2 = left, 3 = right,
          * 4 = upper, 5 = lower */
diff --git a/src/main/java/org/dynmap/hdmap/TopoHDShader.java b/src/main/java/org/dynmap/hdmap/TopoHDShader.java
new file mode 100644
index 00000000..02dbce18
--- /dev/null
+++ b/src/main/java/org/dynmap/hdmap/TopoHDShader.java
@@ -0,0 +1,236 @@
+package org.dynmap.hdmap;
+
+import static org.dynmap.JSONUtils.s;
+
+import org.bukkit.World.Environment;
+import org.dynmap.Color;
+import org.dynmap.ConfigurationNode;
+import org.dynmap.Log;
+import org.dynmap.MapManager;
+import org.dynmap.utils.MapChunkCache;
+import org.dynmap.utils.MapIterator;
+import org.dynmap.utils.MapIterator.BlockStep;
+import org.json.simple.JSONObject;
+
+public class TopoHDShader implements HDShader {
+    private String name;
+    private Color linecolor;  /* Color for topo lines */
+    private Color fillcolor[];  /* Color for nontopo surfaces */
+    private Color watercolor;
+    
+    private Color readColor(String id, ConfigurationNode cfg) {
+        String lclr = cfg.getString(id, null);
+        if((lclr != null) && (lclr.startsWith("#"))) {
+            try {
+                int c = Integer.parseInt(lclr.substring(1), 16);
+                return new Color((c>>16)&0xFF, (c>>8)&0xFF, c&0xFF);
+            } catch (NumberFormatException nfx) {
+                Log.severe("Invalid color value: " + lclr + " for '" + id + "'");
+            }
+        }
+        return null;
+    }
+    public TopoHDShader(ConfigurationNode configuration) {
+        name = (String) configuration.get("name");
+        
+        fillcolor = new Color[128];   /* Color by Y */
+        /* Load defined colors from parameters */
+        for(int i = 0; i < 128; i++) {
+            fillcolor[i] = readColor("color" + i,  configuration);
+        }
+        linecolor = readColor("linecolor",  configuration);
+        watercolor = readColor("watercolor",  configuration);
+        /* Now, interpolate missing colors */
+        if(fillcolor[0] == null) {
+            fillcolor[0] = new Color(0, 0, 0);
+        }
+        if(fillcolor[127] == null) {
+            fillcolor[127] = new Color(255, 255, 255);
+        }
+        int starty = 0;
+        for(int i = 1; i < 128; i++) {
+            if(fillcolor[i] != null) {  /* Found color? */
+                int delta = i - starty;
+                Color c0 = fillcolor[starty];
+                Color c1 = fillcolor[i];
+                /* Interpolate missing colors since last one */
+                for(int j = 1; j < delta; j++) {
+                    fillcolor[starty + j] = new Color((c0.getRed()*(delta-j) + c1.getRed()*j)/delta, (c0.getGreen()*(delta-j) + c1.getGreen()*j)/delta, (c0.getBlue()*(delta-j) + c1.getBlue()*j)/delta);
+                }
+                starty = i;  /* New start color */
+            }
+        }
+    }
+    
+    @Override
+    public boolean isBiomeDataNeeded() { 
+        return false; 
+    }
+    
+    @Override
+    public boolean isRawBiomeDataNeeded() { 
+        return false; 
+    }
+    
+    @Override
+    public boolean isHightestBlockYDataNeeded() {
+        return false;
+    }
+
+    @Override
+    public boolean isBlockTypeDataNeeded() {
+        return true;
+    }
+
+    @Override
+    public boolean isSkyLightLevelNeeded() {
+        return false;
+    }
+
+    @Override
+    public boolean isEmittedLightLevelNeeded() {
+        return false;
+    }
+
+    @Override
+    public String getName() {
+        return name;
+    }
+    
+    private class OurShaderState implements HDShaderState {
+        private Color color[];
+        private Color tmpcolor[];
+        private Color c;
+        protected MapIterator mapiter;
+        protected HDMap map;
+        private HDLighting lighting;
+        private int scale;
+        
+        private OurShaderState(MapIterator mapiter, HDMap map, MapChunkCache cache) {
+            this.mapiter = mapiter;
+            this.map = map;
+            this.lighting = map.getLighting();
+            if(lighting.isNightAndDayEnabled()) {
+                color = new Color[] { new Color(), new Color() };
+                tmpcolor = new Color[] { new Color(), new Color() };
+            }
+            else {
+                color = new Color[] { new Color() };
+                tmpcolor = new Color[] { new Color() };
+            }
+            scale = (int)map.getPerspective().getScale();
+            c = new Color();
+        }
+        /**
+         * Get our shader
+         */
+        public HDShader getShader() {
+            return TopoHDShader.this;
+        }
+
+        /**
+         * Get our map
+         */
+        public HDMap getMap() {
+            return map;
+        }
+        
+        /**
+         * Get our lighting
+         */
+        public HDLighting getLighting() {
+            return lighting;
+        }
+        
+        /**
+         * Reset renderer state for new ray
+         */
+        public void reset(HDPerspectiveState ps) {
+            for(int i = 0; i < color.length; i++)
+                color[i].setTransparent();
+        }
+        
+        /**
+         * Process next ray step - called for each block on route
+         * @return true if ray is done, false if ray needs to continue
+         */
+        public boolean processBlock(HDPerspectiveState ps) {
+            int blocktype = ps.getBlockTypeID();
+            
+            if(blocktype == 0) {
+                return false;
+            }
+            /* See if we're close to an edge */
+            int[] xyz = ps.getSubblockCoord();
+            /* See which face we're on (only do lines on top face) */
+            switch(ps.getLastBlockStep()) {
+            case Y_MINUS:
+            case Y_PLUS:
+                if((linecolor != null) &&
+                        (((xyz[0] == 0) && (mapiter.getBlockTypeIDAt(BlockStep.X_MINUS) == 0)) ||
+                        ((xyz[0] == (scale-1)) && (mapiter.getBlockTypeIDAt(BlockStep.X_PLUS) == 0)) ||
+                        ((xyz[2] == 0) && (mapiter.getBlockTypeIDAt(BlockStep.Z_MINUS) == 0)) ||
+                        ((xyz[2] == (scale-1)) && (mapiter.getBlockTypeIDAt(BlockStep.Z_PLUS) == 0)))) {
+                    c.setColor(linecolor);
+                }
+                else if((watercolor != null) && ((blocktype == 8) || (blocktype == 9))) {
+                    c.setColor(watercolor);
+                }
+                else {
+                    c.setColor(fillcolor[mapiter.getY()]);
+                }
+                break;
+            default:
+                if((linecolor != null) && (xyz[1] == (scale-1)))
+                    c.setColor(linecolor);
+                else if((watercolor != null) && ((blocktype == 8) || (blocktype == 9))) {
+                    c.setColor(watercolor);
+                }
+                else
+                    c.setColor(fillcolor[mapiter.getY()]);
+                break;
+            }
+            /* Handle light level, if needed */
+            lighting.applyLighting(ps, this, c, tmpcolor);
+
+            for(int i = 0; i < color.length; i++)
+                color[i] = tmpcolor[i];
+
+            return true;
+        }        
+        /**
+         * Ray ended - used to report that ray has exited map (called if renderer has not reported complete)
+         */
+        public void rayFinished(HDPerspectiveState ps) {
+        }
+        /**
+         * Get result color - get resulting color for ray
+         * @param c - object to store color value in
+         * @param index - index of color to request (renderer specific - 0=default, 1=day for night/day renderer
+         */
+        public void getRayColor(Color c, int index) {
+            c.setColor(color[index]);
+        }
+        /**
+         * Clean up state object - called after last ray completed
+         */
+        public void cleanup() {
+        }
+    }
+
+    /**
+     *  Get renderer state object for use rendering a tile
+     * @param map - map being rendered
+     * @param cache - chunk cache containing data for tile to be rendered
+     * @param mapiter - iterator used when traversing rays in tile
+     * @return state object to use for all rays in tile
+     */
+    public HDShaderState getStateInstance(HDMap map, MapChunkCache cache, MapIterator mapiter) {
+        return new OurShaderState(mapiter, map, cache);
+    }
+    
+    /* Add shader's contributions to JSON for map object */
+    public void addClientConfiguration(JSONObject mapObject) {
+        s(mapObject, "shader", name);
+    }
+}
diff --git a/src/main/resources/shaders.txt b/src/main/resources/shaders.txt
index e13fae30..e0d86c5a 100644
--- a/src/main/resources/shaders.txt
+++ b/src/main/resources/shaders.txt
@@ -58,3 +58,19 @@ shaders:
     name: stdtexture-nobiome
     texturepack: standard
     biomeshaded: false
+    
+  # Topological map shader    
+  - class: org.dynmap.hdmap.TopoHDShader
+    name: topo
+    color127: "#FFFFFF"
+    color111: "#8B4513"
+    color95: "#D2B48C"
+    color79: "#FFFF00"
+    color63: "#008000"
+    color47: "#228B22"
+    color31: "#104010"
+    color15: "#6B8E23"
+    color0: "#696969"
+    linecolor: "#000000"
+    watercolor: "#0000FF"
+    
\ No newline at end of file