Add a /filesize/ page

_data/datasets.yml

@@ -5,6 +5,7 @@
   json-size: 7.0
   gml: 9-284-556.gml
   gml-size: 57
+  gml-size-wo: 40
   # textures: none
   validity: 98% buildings valid
   details: "Buildings in LoD 0, 1.2, 1.3, 2.2; multiple attributes"
@@ -15,6 +16,7 @@
   json-size: 293
   gml: Zurich_Building_LoD2_V10.gml
   gml-size: 2990
+  gml-size-wo: 2100
   # textures: none
   validity: 76% buildings valid
   details: "Buildings in LoD2"
@@ -26,6 +28,7 @@
   json-size: 2.7
   gml:  DenHaag_01.xml
   gml-size: 30
+  gml-size-wo: 19
   # textures: none
   validity: 62% features valid
   details: "'Tile 01', Buildings (in LoD2) and Terrain are merged"
@@ -37,6 +40,7 @@
   json-size: 5.6
   gml:  VM05_2009.gml
   gml-size: 75
+  gml-size-wo: 53
   # textures: none
   validity: 86% buildings valid
   details: Tile 'VM05'. Buildings in LoD2
@@ -48,6 +52,7 @@
   json-size: 110
   gml:  DA13_3D_Buildings_Merged.gml
   gml-size: 980
+  gml-size-wo: 682
   # textures: none
   validity: 99.9% buildings are valid (only 21 are invalid)
   details: Tile 'DA13'. Buildings in LoD2
@@ -59,6 +64,7 @@
   json-size: 2.7
   gml:  3-20-DELFSHAVEN.xml
   gml-size: 25
+  gml-size-wo: 18
   textures: 3-20-DELFSHAVEN.zip
   validity: 76% buildings valid
   details: Neighbourhood 'Delfshaven'. Buildings in LoD2
@@ -70,6 +76,7 @@
   json-size: 4.5
   gml:  LoD3_Railway.gml
   gml-size: 50
+  gml-size-wo: 39
   textures: LoD3_Railway.zip
   validity: 74% features valid
   details: CityGML demo. Buildings, Railway, Terrain, Vegetation (with Geometry Templates), Water, Tunnels
@@ -81,6 +88,7 @@
   json-size: 5.6
   gml:  Vienna_102081.gml
   gml-size: 58
-  # textures: none
+  gml-size-wo: 40
+  textures: none
   validity: 98.5% buildings valid
   details: Buildings in LoD2  

datasets/index.md

@@ -54,7 +54,7 @@ Please be aware that we simply converted the datasets, some datasets contain (ge
 <table >
   <tr>
     <th>dataset</th>
-    <th>CityGML file (size)</th>
+    <th>CityGML-XML file (size)</th>
     <th>CityJSON file (size)</th>
     <th>textures</th>
     <th><a href="https://github.com/tudelft3d/val3dity">geometric validity</a></th>
@@ -78,7 +78,7 @@ Please be aware that we simply converted the datasets, some datasets contain (ge
   {% endfor %}
 </table>
 
-<i class="fas fa-exclamation-circle"></i> It should be observed that on average CityJSON compresses ~6X a CityGML, and that without any loss of information ([see details](https://github.com/cityjson/specs/wiki/Compression-factor-for-a-few-open-CityGML-datasets)).
+<i class="fas fa-exclamation-circle"></i> On average CityJSON compresses ~7X a CityGML-XML file, and that without any loss of information ([see more details]({{ '/filesize/' | prepend: site.baseurl }})).
 
 <i class="fas fa-exclamation-circle"></i> We performed the geometric validation with [val3dity](https://github.com/tudelft3d/val3dity) and report the overall result in the column 'validity'. To understand the errors, we suggest validating the files ([how to do this]({{ '/tutorials/validation/' | relative_url }})) yourself.
 

filesize/index.md

@@ -0,0 +1,67 @@
+---
+layout: default
+title: File size 
+nav_exclude: true
+permalink: /filesize/
+---
+
+# File size
+
+## Table of contents
+{: .no_toc .text-delta }
+
+1. TOC
+{:toc}
+
+---
+
+
+## CityJSON vs CityGML-XML: 7X compression
+
+{% assign ds = site.data.datasets | sort: 'name' %}
+
+<table >
+  <tr>
+    <th>dataset</th>
+    <th>CityJSON v2.0</th>
+    <th>CityGML-XML v3.0</th>
+    <th>textures</th>
+    <th>details</th>
+    <th>compression</th>
+  </tr>
+  {% for i in ds %}
+    <tr>
+      <td><a href="{{ i.url }}">{{ i.name }}</a></td>
+      <td>{{ i.json-size }}MB (<a href="https://3d.bk.tudelft.nl/opendata/cityjson/3dcities/v2.0/{{ i.json }}">download)</a></td>
+      <td>{{ i.gml-size-wo }}MB (<a href="https://3d.bk.tudelft.nl/opendata/cityjson/3dcities/citygml/{{ i.gml }}">download</a>)</td>
+      <td>
+        {% if i.textures %}
+          <a href="https://3d.bk.tudelft.nl/opendata/cityjson/3dcities/citygml/{{ i.textures }}">[ZIP]</a>
+        {% else %}
+          none
+        {% endif %}
+      </td>
+      <td>{{ i.details }}</td>
+      <td><b>{{ i.gml-size-wo | divided_by: i.json-size | round: 1 }}X</b></td>
+    </tr>
+  {% endfor %}
+</table>
+
+<i class="fas fa-exclamation-circle"></i> Observe that the file size doesn't take into account the size of the textures files (PNG, JPG, etc) since CityJSON refers to the same ones.
+
+<i class="fas fa-exclamation-circle"></i> CityGML-XML files have all the carriage returns, tabs and spaces removed with this script, for a fair estimation of the compression factor. 
+
+<i class="fas fa-exclamation-circle"></i> CityJSON files do not contain CR or spaces or any formatting.
+
+
+- - -
+
+## CityJSON compared to traditional computer graphic formats
+
+This very nice study ([evaluation of file formats in the context of geo-referenced 3D geometries](https://github.com/FHOOEAIST/geofiles)) compares several file formats for 3D geometries, with a focus on geographical datasets.
+
+The outcome is that CityJSON is nearly as compact as much simpler formats (OBJ, STL, OFF), and it still allows different CRS, textures, complex attributes, complex geometries, etc.
+
+The [summary graph](https://github.aist.science/geofiles/) is particulary nice, click to get an interactive graph!
+
+[![](summary.png)](https://github.aist.science/geofiles/)

index.md

@@ -43,9 +43,9 @@ It was designed with programmers in mind, so that tools and APIs supporting it c
 We believe that you should use CityJSON because: 
 
   1. its simplicity means adding CityJSON support to your software is easy, [many software already support it]({{ "/software/" | prepend: site.baseurl }}) 
-  2. you can in one-click convert CityGML files to CityJSON files, and vice versa, with the open-source tool [citygml-tools](https://github.com/citygml4j/citygml-tools); we even have a [tutorial]({{ "/tutorials/conversion/" | prepend: site.baseurl }})
-  3. files are on average [6X more compact](https://github.com/cityjson/specs/wiki/Compression-factor-for-a-few-open-CityGML-datasets) than their CityGML equivalent
-  4. you can automatically convert to/from CityGML v3.0 XML files with the excellent [citygml-tools](https://github.com/citygml4j/citygml-tools) 
+  2. you can in one-click convert CityGML-XML files to CityJSON files, and vice versa, with the open-source tool [citygml-tools](https://github.com/citygml4j/citygml-tools); we even have a [tutorial]({{ "/tutorials/conversion/" | prepend: site.baseurl }})
+  3. files are on average [7X more compact]({{ '/filesize/' | prepend: site.baseurl }}) than their CityGML-XML equivalent
+  4. you can automatically convert to/from CityGML-XML v3.0 files with the excellent [citygml-tools](https://github.com/citygml4j/citygml-tools) 
   5. there is a [web-viewer](https://viewer.cityjson.org) where you can drag-and-drop a file
   6. you can easily manipulate files with [cjio](https://github.com/cityjson/cjio), you can for instance merge files, remove/filter objects, change the CRS, manage the textures, etc.
   7. you can *easily* define [Extensions]({{ "/extensions/" | prepend: site.baseurl }}) to the core model