Update website

mbloch · mbloch · commit 246fa621ad07 · 2026-05-08T17:57:10.000-04:00
diff --git a/docs/examples/data/globe.msx b/docs/examples/data/globe.msx
diff --git a/docs/examples/data/ny-state.msx b/docs/examples/data/ny-state.msx
diff --git a/docs/examples/data/us-states.msx b/docs/examples/data/us-states.msx
diff --git a/docs/examples/data/us-states.svg b/docs/examples/data/us-states.svg
diff --git a/docs/guides/geojson-for-web-maps.html b/docs/guides/geojson-for-web-maps.html
@@ -58,7 +58,7 @@ <h3 id="export-geojson-for-leaflet-maplibre-mapbox-gl-and-most-web-map-apis">Exp
 <p>If you&#39;re unsure what CRS your data file is using, you can look it up using mapshaper&#39;s <code>-info</code> command. It will give you the CRS in proj4 format, which is used by Mapshaper&#39;s <code>-proj</code> command.</p>
 <pre><code class="hljs language-bash">mapshaper input.shp -info
 </code></pre>
-<p>If your input is a (non-standard) GeoJSON of TopoJSON file with projected coordinates, you&#39;ll have to tell Mapshaper what CRS the coordinates are in before reprojecting. If you do not know the CRS, look for documentation on the source dataset&#39;s CRS. In the example below, you would replace <code>EPSG:3857</code> (Web Mercator) with the correct source CRS.</p>
+<p>If your input is a (non-standard) GeoJSON or TopoJSON file with projected coordinates, you&#39;ll have to tell Mapshaper what CRS the coordinates are in before reprojecting. If you do not know the CRS, look for documentation on the source dataset&#39;s CRS. In the example below, you would replace <code>EPSG:3857</code> (Web Mercator) with the correct source CRS.</p>
 <pre><code class="hljs language-bash">mapshaper projected.geojson \
   -proj init=EPSG:3857 \
   -proj wgs84 \
diff --git a/docs/guides/geojson-for-web-maps.html.md b/docs/guides/geojson-for-web-maps.html.md
@@ -23,7 +23,7 @@ If you're unsure what CRS your data file is using, you can look it up using maps
 mapshaper input.shp -info
 ```
 
-If your input is a (non-standard) GeoJSON of TopoJSON file with projected coordinates, you'll have to tell Mapshaper what CRS the coordinates are in before reprojecting. If you do not know the CRS, look for documentation on the source dataset's CRS. In the example below, you would replace `EPSG:3857` (Web Mercator) with the correct source CRS.
+If your input is a (non-standard) GeoJSON or TopoJSON file with projected coordinates, you'll have to tell Mapshaper what CRS the coordinates are in before reprojecting. If you do not know the CRS, look for documentation on the source dataset's CRS. In the example below, you would replace `EPSG:3857` (Web Mercator) with the correct source CRS.
 
 ```bash
 mapshaper projected.geojson \
diff --git a/docs/guides/projections.html b/docs/guides/projections.html
@@ -103,11 +103,15 @@ <h2 id="auto-fitted-parameters">Auto-fitted parameters</h2>
 <p>For some conic and cylindrical projections, you can supply just the projection name and Mapshaper will calculate suitable parameters from the extent of the data. This is useful when you want a locally appropriate projection without looking up specific values.</p>
 <p>For <strong>Lambert Conformal Conic</strong> (<code>lcc</code>) and <strong>Albers Equal Area Conic</strong> (<code>aea</code>), Mapshaper calculates the central meridian (<code>lon_0</code>) and two standard parallels (<code>lat_1</code>, <code>lat_2</code>) using the one-sixth rule applied to the data&#39;s bounding box.</p>
 <p>For <strong>Transverse Mercator</strong> (<code>tmerc</code>, <code>etmerc</code>), it calculates the central meridian and latitude of origin (<code>lon_0</code>, <code>lat_0</code>) from the center of the bounding box.</p>
+<p>For <strong>Universal Transverse Mercator</strong> (<code>utm</code>), it calculates the UTM zone from the center longitude of the bounding box and adds <code>+south</code> when the center latitude is in the southern hemisphere.</p>
 <pre><code class="hljs language-bash"><span class="hljs-comment"># Mapshaper fills in lon_0, lat_1, lat_2 based on the data extent</span>
 mapshaper region.geojson -proj lcc -o region_lcc.geojson
 
 <span class="hljs-comment"># Equivalent — Mapshaper fills in lon_0 and lat_0</span>
 mapshaper region.geojson -proj tmerc -o region_tmerc.geojson
+
+<span class="hljs-comment"># Equivalent — Mapshaper fills in zone and hemisphere</span>
+mapshaper region.geojson -proj utm -o region_utm.geojson
 </code></pre>
 <p>When Mapshaper auto-fits parameters, it prints the expanded PROJ string so you can see exactly what was applied — for example: <code>Converted &quot;lcc&quot; to &quot;+proj=lcc +lon_0=-95.5 +lat_1=30.17 +lat_2=44.83&quot;</code>. You can copy that string and use it explicitly if you need reproducible output.</p>
 <h2 id="albersusa">albersusa</h2>
diff --git a/docs/guides/projections.html.md b/docs/guides/projections.html.md
@@ -62,12 +62,17 @@ For **Lambert Conformal Conic** (`lcc`) and **Albers Equal Area Conic** (`aea`),
 
 For **Transverse Mercator** (`tmerc`, `etmerc`), it calculates the central meridian and latitude of origin (`lon_0`, `lat_0`) from the center of the bounding box.
 
+For **Universal Transverse Mercator** (`utm`), it calculates the UTM zone from the center longitude of the bounding box and adds `+south` when the center latitude is in the southern hemisphere.
+
 ```bash
 # Mapshaper fills in lon_0, lat_1, lat_2 based on the data extent
 mapshaper region.geojson -proj lcc -o region_lcc.geojson
 
 # Equivalent — Mapshaper fills in lon_0 and lat_0
 mapshaper region.geojson -proj tmerc -o region_tmerc.geojson
+
+# Equivalent — Mapshaper fills in zone and hemisphere
+mapshaper region.geojson -proj utm -o region_utm.geojson
 ```
 
 When Mapshaper auto-fits parameters, it prints the expanded PROJ string so you can see exactly what was applied — for example: `Converted "lcc" to "+proj=lcc +lon_0=-95.5 +lat_1=30.17 +lat_2=44.83"`. You can copy that string and use it explicitly if you need reproducible output.
diff --git a/docs/guides/simplification.html b/docs/guides/simplification.html
@@ -64,8 +64,8 @@ <h2 id="choosing-a-method">Choosing a method</h2>
 <img src="/docs/images/simplification-mod2.png" alt="image"></p>
 <p>Same file using Douglas-Peucker, also 5% simplification.
 <img src="/docs/images/simplification-dp.png" alt="image"></p>
-<p>Zoomed-in view of Norwegian coastline at 5% simplification; left: weighted Visvalingam, right: Douglas-Peucker.
-<img src="/docs/images/simplification-detail.png" alt="image"></p>
+<p>Zoomed-in view of Norwegian coastline at 5% simplification; left: weighted Visvalingam, right: Douglas-Peucker. These figures illustrate the different ways each method removes detail. In a finished map, you would apply far less simplification than this — simplification artifacts generally should not be discernible to the naked eye.</p>
+<p><img src="/docs/images/simplification-detail.png" alt="image"></p>
 <h2 id="simplification-amount">Simplification amount</h2>
 <p>On the command line, there are three ways to specify the amount of simplification to apply: <code>percentage</code>, <code>interval</code>, and <code>resolution</code>.</p>
 <p>Percentage is the default (you don&#39;t need to type <code>percentage=</code>). It gives the percentage of removable vertices to retain, so lower numbers = more simplification.</p>
diff --git a/docs/guides/simplification.html.md b/docs/guides/simplification.html.md
@@ -27,7 +27,8 @@ Natural Earth 10m coastlines, simplified with modified Visvalingam at 5% point r
 Same file using Douglas-Peucker, also 5% simplification.
 ![image](/docs/images/simplification-dp.png)
 
-Zoomed-in view of Norwegian coastline at 5% simplification; left: weighted Visvalingam, right: Douglas-Peucker.
+Zoomed-in view of Norwegian coastline at 5% simplification; left: weighted Visvalingam, right: Douglas-Peucker. These figures illustrate the different ways each method removes detail. In a finished map, you would apply far less simplification than this — simplification artifacts generally should not be discernible to the naked eye.
+
 ![image](/docs/images/simplification-detail.png)
 
 ## Simplification amount
diff --git a/docs/reference.html b/docs/reference.html
@@ -703,7 +703,7 @@ <h2 id="editing-commands" class="cmd-category">Editing Commands</h2>
 </section>
 <section class="cmd-section" data-id="-proj" data-name="-proj" data-options="crs densify match init target"><h3 id="-proj">-proj</h3>
 <p>Project a dataset using a PROJ string, EPSG code or alias. This command affects all layers in the dataset(s) containing the targeted layer or layers. Information on PROJ string syntax can be found on the <a href="https://proj.org/usage/index.html">PROJ website</a>.</p>
-<p><code>&lt;crs&gt;</code> or <code>crs=</code>  Target CRS, given as a Proj.4 definition or an alias. Use the <a href="#-projections"><code>-projections</code></a> command to list available projections and aliases.  In projections which require additional parameters, such as a zone in UTM, you can pass a Proj4 string enclosed in quotes.  For example, <code>crs=&#39;+proj=utm +zone=27&#39;</code>.</p>
+<p><code>&lt;crs&gt;</code> or <code>crs=</code>  Target CRS, given as a Proj.4 definition or an alias. Use the <a href="#-projections"><code>-projections</code></a> command to list available projections and aliases. In some projections that require additional parameters, Mapshaper can fit parameters automatically from the data extent, for example <code>crs=utm</code> selects a UTM zone. You can also pass a Proj4 string enclosed in quotes, for example <code>crs=&#39;+proj=utm +zone=27&#39;</code>.</p>
 <p><code>densify</code> Interpolate vertices along long line segments as needed to approximate curved lines.</p>
 <p><code>match=</code> Match the projection of the given layer or .prj file.</p>
 <p><code>init=</code> Define the pre-projected coordinate system, if unknown. This option is not needed if the source coordinate system is defined by a .prj file, or if the source CRS is WGS84. As with <code>crs</code>, you can pass a Proj4 string enclosed in quotes if the selected projection requires extra parameters, for example <code>init=&#39;+proj=utm +zone=33&#39;</code>.</p>
diff --git a/docs/reference.html.md b/docs/reference.html.md
@@ -1059,7 +1059,7 @@ Common options: `target=`
 
 Project a dataset using a PROJ string, EPSG code or alias. This command affects all layers in the dataset(s) containing the targeted layer or layers. Information on PROJ string syntax can be found on the [PROJ website](https://proj.org/usage/index.html).
 
-`<crs>` or `crs=`  Target CRS, given as a Proj.4 definition or an alias. Use the [`-projections`](#-projections) command to list available projections and aliases.  In projections which require additional parameters, such as a zone in UTM, you can pass a Proj4 string enclosed in quotes.  For example, `crs='+proj=utm +zone=27'`.
+`<crs>` or `crs=`  Target CRS, given as a Proj.4 definition or an alias. Use the [`-projections`](#-projections) command to list available projections and aliases. In some projections that require additional parameters, Mapshaper can fit parameters automatically from the data extent, for example `crs=utm` selects a UTM zone. You can also pass a Proj4 string enclosed in quotes, for example `crs='+proj=utm +zone=27'`.
 
 `densify` Interpolate vertices along long line segments as needed to approximate curved lines.
 
diff --git a/llms-full.txt b/llms-full.txt
@@ -1207,7 +1207,7 @@ Common options: `target=`
 
 Project a dataset using a PROJ string, EPSG code or alias. This command affects all layers in the dataset(s) containing the targeted layer or layers. Information on PROJ string syntax can be found on the [PROJ website](https://proj.org/usage/index.html).
 
-`<crs>` or `crs=`  Target CRS, given as a Proj.4 definition or an alias. Use the [`-projections`](#-projections) command to list available projections and aliases.  In projections which require additional parameters, such as a zone in UTM, you can pass a Proj4 string enclosed in quotes.  For example, `crs='+proj=utm +zone=27'`.
+`<crs>` or `crs=`  Target CRS, given as a Proj.4 definition or an alias. Use the [`-projections`](#-projections) command to list available projections and aliases. In some projections that require additional parameters, Mapshaper can fit parameters automatically from the data extent, for example `crs=utm` selects a UTM zone. You can also pass a Proj4 string enclosed in quotes, for example `crs='+proj=utm +zone=27'`.
 
 `densify` Interpolate vertices along long line segments as needed to approximate curved lines.
 
@@ -2770,7 +2770,8 @@ Natural Earth 10m coastlines, simplified with modified Visvalingam at 5% point r
 Same file using Douglas-Peucker, also 5% simplification.
 ![image](/docs/images/simplification-dp.png)
 
-Zoomed-in view of Norwegian coastline at 5% simplification; left: weighted Visvalingam, right: Douglas-Peucker.
+Zoomed-in view of Norwegian coastline at 5% simplification; left: weighted Visvalingam, right: Douglas-Peucker. These figures illustrate the different ways each method removes detail. In a finished map, you would apply far less simplification than this — simplification artifacts generally should not be discernible to the naked eye.
+
 ![image](/docs/images/simplification-detail.png)
 
 ## Simplification amount
@@ -3508,12 +3509,17 @@ For **Lambert Conformal Conic** (`lcc`) and **Albers Equal Area Conic** (`aea`),
 
 For **Transverse Mercator** (`tmerc`, `etmerc`), it calculates the central meridian and latitude of origin (`lon_0`, `lat_0`) from the center of the bounding box.
 
+For **Universal Transverse Mercator** (`utm`), it calculates the UTM zone from the center longitude of the bounding box and adds `+south` when the center latitude is in the southern hemisphere.
+
 ```bash
 # Mapshaper fills in lon_0, lat_1, lat_2 based on the data extent
 mapshaper region.geojson -proj lcc -o region_lcc.geojson
 
 # Equivalent — Mapshaper fills in lon_0 and lat_0
 mapshaper region.geojson -proj tmerc -o region_tmerc.geojson
+
+# Equivalent — Mapshaper fills in zone and hemisphere
+mapshaper region.geojson -proj utm -o region_utm.geojson
 ```
 
 When Mapshaper auto-fits parameters, it prints the expanded PROJ string so you can see exactly what was applied — for example: `Converted "lcc" to "+proj=lcc +lon_0=-95.5 +lat_1=30.17 +lat_2=44.83"`. You can copy that string and use it explicitly if you need reproducible output.
@@ -3741,7 +3747,7 @@ If you're unsure what CRS your data file is using, you can look it up using maps
 mapshaper input.shp -info
 ```
 
-If your input is a (non-standard) GeoJSON of TopoJSON file with projected coordinates, you'll have to tell Mapshaper what CRS the coordinates are in before reprojecting. If you do not know the CRS, look for documentation on the source dataset's CRS. In the example below, you would replace `EPSG:3857` (Web Mercator) with the correct source CRS.
+If your input is a (non-standard) GeoJSON or TopoJSON file with projected coordinates, you'll have to tell Mapshaper what CRS the coordinates are in before reprojecting. If you do not know the CRS, look for documentation on the source dataset's CRS. In the example below, you would replace `EPSG:3857` (Web Mercator) with the correct source CRS.
 
 ```bash
 mapshaper projected.geojson \
diff --git a/mapshaper-gui.js b/mapshaper-gui.js
@@ -6726,13 +6726,11 @@
 
     function message() {
       var msg = GUI.formatMessageArgs(arguments);
-      if (gui.notify) {
-        gui.notify({severity: 'info', body: msg});
-      } else {
+      if (!gui.notify) {
         // Fallback for early messages before MessageControl is constructed
         gui.message(msg);
-        internal.logArgs(arguments);
       }
+      internal.logArgs(arguments);
     }
 
     // CLI warnings used to surface as modal alerts, which interrupt the user
diff --git a/mapshaper.js b/mapshaper.js
