v0.6.85

CHANGELOG.md

@@ -1,3 +1,6 @@
+v0.6.85
+* Added -rectangles bbox=<expression> option, which uses an expression to generate rectangle coords for each feature.
+
 v0.6.84
 * Catch a polygon drawing error.
 

package.json

@@ -1,6 +1,6 @@
 {
   "name": "mapshaper",
-  "version": "0.6.84",
+  "version": "0.6.85",
   "description": "A tool for editing vector datasets for mapping and GIS.",
   "keywords": [
     "shapefile",

src/cli/mapshaper-options.mjs

@@ -1330,8 +1330,11 @@ export function getOptionParser() {
     .option('no-replace', noReplaceOpt);
 
   parser.command('rectangles')
-    .describe('create a rectangle around each feature in a layer')
+    .describe('create a rectangle for each feature in a layer')
     .option('offset', offsetOpt)
+    .option('bbox', {
+      describe: 'Use an expression to generate a rectangle for each feature'
+    })
     .option('aspect-ratio', aspectRatioOpt)
     .option('name', nameOpt)
     .option('target', targetOpt)

src/commands/mapshaper-rectangle.mjs

@@ -6,7 +6,8 @@ import {
   layerHasGeometry,
   setOutputLayerName,
   initDataTable,
-  layerIsRectangle
+  layerIsRectangle,
+  getFeatureCount
 } from '../dataset/mapshaper-layer-utils';
 import { mergeDatasetsIntoDataset } from '../dataset/mapshaper-merging';
 import { importGeoJSON } from '../geojson/geojson-import';
@@ -17,21 +18,24 @@ import { probablyDecimalDegreeBounds, clampToWorldBounds } from '../geom/mapshap
 import { Bounds } from '../geom/mapshaper-bounds';
 import { densifyPathByInterval } from '../crs/mapshaper-densify';
 import { bboxToCoords } from '../paths/mapshaper-rectangle-utils';
+import { compileFeatureExpression } from '../expressions/mapshaper-feature-expressions';
 
 // Create rectangles around each feature in a layer
 cmd.rectangles = function(targetLyr, targetDataset, opts) {
-  if (!layerHasGeometry(targetLyr)) {
-    stop("Layer is missing geometric shapes");
-  }
   var crsInfo = getDatasetCrsInfo(targetDataset);
   var records = targetLyr.data ? targetLyr.data.getRecords() : null;
-  var geometries = targetLyr.shapes.map(function(shp) {
-    var bounds = targetLyr.geometry_type == 'point' ?
-      getPointFeatureBounds(shp) : targetDataset.arcs.getMultiShapeBounds(shp);
-    bounds = applyRectangleOptions(bounds, crsInfo.crs, opts);
-    if (!bounds) return null;
-    return bboxToPolygon(bounds.toArray(), opts);
-  });
+  var geometries;
+
+  if (opts.bbox) {
+    geometries = bboxExpressionToGeometries(opts.bbox, targetLyr, targetDataset, opts);
+
+  } else {
+    if (!layerHasGeometry(targetLyr)) {
+      stop("Layer is missing geometric shapes");
+    }
+    geometries = shapesToBoxGeometries(targetLyr, targetDataset, opts);
+  }
+
   var geojson = {
     type: 'FeatureCollection',
     features: geometries.map(function(geom, i) {
@@ -53,6 +57,39 @@ cmd.rectangles = function(targetLyr, targetDataset, opts) {
   return outputLayers;
 };
 
+function shapesToBoxGeometries(lyr, dataset, opts) {
+  var crsInfo = getDatasetCrsInfo(dataset);
+  return lyr.shapes.map(function(shp) {
+    var bounds = lyr.geometry_type == 'point' ?
+      getPointFeatureBounds(shp) : dataset.arcs.getMultiShapeBounds(shp);
+    bounds = applyRectangleOptions(bounds, crsInfo.crs, opts);
+    if (!bounds) return null;
+    return bboxToPolygon(bounds.toArray(), opts);
+  });
+}
+
+function bboxExpressionToGeometries(exp, lyr, dataset, opts) {
+  var compiled = compileFeatureExpression(exp, lyr, dataset.arcs, {});
+  var n = getFeatureCount(lyr);
+  var result;
+  var geometries = [];
+  for (var i=0; i<n; i++) {
+    result = compiled(i);
+    if (!looksLikeBbox(result)) {
+      stop('Invalid bbox value (expected a GeoJSON-type bbox):', result);
+    }
+    geometries.push(bboxToPolygon(result));
+  }
+  return geometries;
+}
+
+function looksLikeBbox(o) {
+  if (!o || o.length != 4) return false;
+  if (o.some(isNaN)) return false;
+  if (o[0] <= o[2] == false || o[1] <= o[3] == false) return false;
+  return true;
+}
+
 // Create rectangles around one or more target layers
 //
 cmd.rectangle2 = function(target, opts) {

test/rectangle-test.mjs

@@ -5,6 +5,15 @@ var Bounds = api.internal.Bounds;
 
 describe('mapshaper-rectangle.js', function () {
 
+  describe('-rectangles command with bbox= option', async function() {
+    var csv = 'bbox\n"[0,0,1,1]"\n"[2,0,3,1]"';
+    var cmd = '-i data.csv -rectangles bbox="JSON.parse(bbox)" -o data.json';
+    var result = await api.applyCommands(cmd, {'data.csv': csv});
+    var json = JSON.parse(result['data.json']);
+    var coords = json.features[1].geometry.coordinates;
+    assert.deepEqual(coords, [[[2, 0], [3, 0], [3, 1], [2, 1], [2, 0]]]);
+  });
+
   describe('applyAspectRatio()', function () {
     var applyAspectRatio = api.internal.applyAspectRatio;
     it('Handle max ratio', function () {