Storage efficiency of SVG Map
We compared the store efficiency between a SVG Map format, a shapefile format, and GML (GML2).
2008.07.30 update: GeoJSON and KML were added. (They were converted from shapefile respectively with a free converter. )
When there is little information content of a property (metadata), the size of a SVG Map data is almost comparable as Shapefile. The store efficiency of SVGMap falls as the information content of a property increases. Since it is an XML format, the size of SVG Map is likely to become large, but since SVGMap describes almost all informations as not an element but the property of XML, it is relatively efficient.
On the other hand, the size of a GML data is more than double precision compared with them. It will be because GML has specifications which express almost all informations as a hierarchical XML element.
The efficiency of GeoJSON seems to be better than that of GML though it is lower than SVG Map. The efficiency of KML seems not to be good, for it is designed based on GML and is included the drawing style.
| Shapefile | GML | SVG Map | GeoJSON | KML | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| shape (.shp) | property (.dbf + .shx) | summary | (shape + property) | graphic (shape + rendition style ) | graphic + property （embedded metadata） | shape | shape + property | graphic (shape + rendition style ) | graphic +property | |
| １ | 1,025 | 58 | 1,083 | 2,446 | 910 | 1,175 | 1,613 | 1,990 | 2,322 | 5,446 |
| ２ | 10,741 | 7,361 | 18,102 | 59,940 | 10,136 | 21,475 | 14,914 | 28,572 | 29,639 | 160,980 |
| ３ | 156 | 97 | 253 | 1,093 | 136 | 405 | 216 | 527 | 437 | 2,793 |
Unit: KB
- The coastline in Japan which makes the GLOBAL MAP an origin (It has 7 properties)
- The road in Japan which makes the GLOBAL MAP an origin (It has 11 properties)
- The building shape of the Toyonaka digital map sample (It has 13 properties)
