Add -points command with x= and y= options

mapshaper.js

@@ -11616,6 +11616,41 @@ api.mergeFiles = function(files, opts) {
 
 
 
+api.createPointLayer = function(srcLyr, opts) {
+  var data = srcLyr.data,
+      nulls = 0,
+      destLyr;
+
+  if (!data) stop("[points] layer is missing a data table");
+  if (!opts.x || !opts.y || !data.fieldExists(opts.x) || !data.fieldExists(opts.y)) {
+    stop("[points] missing x,y data fields");
+  }
+
+  destLyr = {
+    info: srcLyr.info,
+    geometry_type: 'point',
+    data: opts.no_replace ? data.clone() : data
+  };
+  destLyr.shapes = data.getRecords().map(function(rec) {
+    var x = rec[opts.x],
+        y = rec[opts.y];
+    if (isNaN(x) || isNaN(y)) {
+      nulls++;
+      return null;
+    }
+    return [[x, y]];
+  });
+
+  if (nulls > 0) {
+    message(utils.format('[points] %d/%d points are null', nulls, data.size()));
+  }
+
+  return destLyr;
+};
+
+
+
+
 api.renameLayers = function(layers, names) {
   if (!names || names.length > 0 === false) {
     names = ['layer'];
@@ -12661,6 +12696,9 @@ api.runCommand = function(cmd, dataset, cb) {
     } else if (name == 'o') {
       api.exportFiles(Utils.defaults({layers: targetLayers}, dataset), opts);
 
+    } else if (name == 'points') {
+      newLayers = MapShaper.applyCommand(api.createPointLayer, targetLayers, opts);
+
     } else if (name == 'rename-layers') {
       api.renameLayers(targetLayers, opts.names);
 
@@ -13313,6 +13351,13 @@ function validateLinesOpts(cmd) {
   }
 }
 
+function validatePointsOpts(cmd) {
+  if (!cmd.options.x || !cmd.options.y) {
+    error("command requires names of x and y fields");
+  }
+}
+
+
 function validateInnerLinesOpts(cmd) {
   if (cmd._.length > 0) {
     error("command takes no arguments");
@@ -13737,6 +13782,13 @@ MapShaper.getOptionParser = function() {
     .option("convert-holes", {type: "flag"}) // testing
     .option("target", targetOpt);
 
+  parser.command("innerlines")
+    .describe("convert polygons to polylines along shared boundaries")
+    .validate(validateInnerLinesOpts)
+    .option("name", nameOpt)
+    .option("no-replace", noReplaceOpt)
+    .option("target", targetOpt);
+
   parser.command("lines")
     .describe("convert polygons to classified polylines")
     .validate(validateLinesOpts)
@@ -13749,9 +13801,15 @@ MapShaper.getOptionParser = function() {
     .option("no-replace", noReplaceOpt)
     .option("target", targetOpt);
 
-  parser.command("innerlines")
-    .describe("convert polygons to polylines along shared boundaries")
-    .validate(validateInnerLinesOpts)
+  parser.command("points")
+    .describe("create a point layer from data fields")
+    .validate(validatePointsOpts)
+    .option("x", {
+      describe: "field containing x coordinate"
+    })
+    .option("y", {
+      describe: "field containing y coordinate"
+    })
     .option("name", nameOpt)
     .option("no-replace", noReplaceOpt)
     .option("target", targetOpt);

src/cli/mapshaper-option-validation.js

@@ -165,6 +165,13 @@ function validateLinesOpts(cmd) {
   }
 }
 
+function validatePointsOpts(cmd) {
+  if (!cmd.options.x || !cmd.options.y) {
+    error("command requires names of x and y fields");
+  }
+}
+
+
 function validateInnerLinesOpts(cmd) {
   if (cmd._.length > 0) {
     error("command takes no arguments");

src/cli/mapshaper-options.js

@@ -323,6 +323,13 @@ MapShaper.getOptionParser = function() {
     .option("convert-holes", {type: "flag"}) // testing
     .option("target", targetOpt);
 
+  parser.command("innerlines")
+    .describe("convert polygons to polylines along shared boundaries")
+    .validate(validateInnerLinesOpts)
+    .option("name", nameOpt)
+    .option("no-replace", noReplaceOpt)
+    .option("target", targetOpt);
+
   parser.command("lines")
     .describe("convert polygons to classified polylines")
     .validate(validateLinesOpts)
@@ -335,9 +342,15 @@ MapShaper.getOptionParser = function() {
     .option("no-replace", noReplaceOpt)
     .option("target", targetOpt);
 
-  parser.command("innerlines")
-    .describe("convert polygons to polylines along shared boundaries")
-    .validate(validateInnerLinesOpts)
+  parser.command("points")
+    .describe("create a point layer from data fields")
+    .validate(validatePointsOpts)
+    .option("x", {
+      describe: "field containing x coordinate"
+    })
+    .option("y", {
+      describe: "field containing y coordinate"
+    })
     .option("name", nameOpt)
     .option("no-replace", noReplaceOpt)
     .option("target", targetOpt);

src/cli/mapshaper-run-command.js

@@ -14,6 +14,7 @@ mapshaper-innerlines
 mapshaper-join
 mapshaper-keep-shapes
 mapshaper-merge-files
+mapshaper-points
 mapshaper-rename-layers
 mapshaper-simplify
 mapshaper-split
@@ -108,6 +109,9 @@ api.runCommand = function(cmd, dataset, cb) {
     } else if (name == 'o') {
       api.exportFiles(Utils.defaults({layers: targetLayers}, dataset), opts);
 
+    } else if (name == 'points') {
+      newLayers = MapShaper.applyCommand(api.createPointLayer, targetLayers, opts);
+
     } else if (name == 'rename-layers') {
       api.renameLayers(targetLayers, opts.names);
 

src/commands/mapshaper-points.js

@@ -0,0 +1,33 @@
+/* @requires mapshaper-data-table, mapshaper-dataset-utils */
+
+api.createPointLayer = function(srcLyr, opts) {
+  var data = srcLyr.data,
+      nulls = 0,
+      destLyr;
+
+  if (!data) stop("[points] layer is missing a data table");
+  if (!opts.x || !opts.y || !data.fieldExists(opts.x) || !data.fieldExists(opts.y)) {
+    stop("[points] missing x,y data fields");
+  }
+
+  destLyr = {
+    info: srcLyr.info,
+    geometry_type: 'point',
+    data: opts.no_replace ? data.clone() : data
+  };
+  destLyr.shapes = data.getRecords().map(function(rec) {
+    var x = rec[opts.x],
+        y = rec[opts.y];
+    if (isNaN(x) || isNaN(y)) {
+      nulls++;
+      return null;
+    }
+    return [[x, y]];
+  });
+
+  if (nulls > 0) {
+    message(utils.format('[points] %d/%d points are null', nulls, data.size()));
+  }
+
+  return destLyr;
+};

www/mapshaper.js

@@ -5833,37 +5833,6 @@ geom.getAvgPathXY = function(ids, arcs) {
   };
 };
 
-geom.getPathCentroid = function(ids, arcs) {
-  var iter = arcs.getShapeIter(ids),
-      sum = 0,
-      sumX = 0,
-      sumY = 0,
-      ax, ay, tmp, area;
-  if (!iter.hasNext()) return null;
-  ax = iter.x;
-  ay = iter.y;
-  while (iter.hasNext()) {
-    tmp = ax * iter.y - ay * iter.x;
-    sum += tmp;
-    sumX += tmp * (iter.x + ax);
-    sumY += tmp * (iter.y + ay);
-    ax = iter.x;
-    ay = iter.y;
-  }
-  area = sum / 2;
-  if (area === 0) {
-    return geom.getAvgPathXY(ids, arcs);
-  } else return {
-    x: sumX / (6 * area),
-    y: sumY / (6 * area)
-  };
-};
-
-geom.getShapeCentroid = function(shp, arcs) {
-  var maxPath = geom.getMaxPath(shp, arcs);
-  return maxPath ? geom.getPathCentroid(maxPath, arcs) : null;
-};
-
 // Return true if point is inside or on boundary of a shape
 //
 geom.testPointInShape = function(x, y, shp, arcs) {
@@ -5881,14 +5850,6 @@ geom.testPointInShape = function(x, y, shp, arcs) {
   return isOn || isIn;
 };
 
-// Get a point suitable for anchoring a label
-// Method:
-// - find centroid
-// - ...
-//
-geom.getInteriorPoint = function(shp, arcs) {
-
-};
 
 geom.getPointToPathDistance = function(px, py, ids, arcs) {
   var iter = arcs.getShapeIter(ids);
@@ -9704,7 +9665,7 @@ MapShaper.exportGeoJSONString = function(lyr, arcs, opts) {
       useFeatures = useProperties || opts.id_field,
       stringify = JSON.stringify;
 
-  if (opts.pretty) {
+  if (opts.prettify) {
     stringify = MapShaper.getFormattedStringify(['bbox', 'coordinates']);
   }
   if (properties && properties.length !== lyr.shapes.length) {
@@ -10739,7 +10700,7 @@ MapShaper.exportTopoJSON = function(dataset, opts) {
       stringify = JSON.stringify,
       filename;
 
-  if (opts.pretty) {
+  if (opts.prettify) {
     stringify = MapShaper.getFormattedStringify('coordinates,arcs,bbox,translate,scale'.split(','));
   }
   if (opts.output_file) {