GIS Raster formats: comparative benchmark [take two]

JPEG vs WEBP

Exactly two years ago I've published a quick review about the most popular codecs commonly used in order to store compressed GIS raster imagery.
If you are interested in this, you can learn more by reading my previous (2010) review.

This time I'll simply examine two codecs/formats:

Quick overall comparison

TopicJPEGWEBP
Lossless compressionNo Yes
(claiming to be more effective than PNG)
Lossy compressionYes
selectable quality [100 - 0]
Yes
selectable quality [100 - 0]
RGB colorspaceYes Yes
Grayscale colorspace
[aka Black & White]
Yes Yes
Alpha channel
[aka Transparency]
No Yes
Internal tiled layoutNo Yes
Open Source supporting libraryYes Yes
there are two distinct implementations [API-ABI compatible]:
libjpeg [Independent JPEG Group]
custom free software licence
libjpeg-turbo [community project]
BSD-like license
libwebp [Google developers]
BSD license
Supporting applicationsAlmost universal Limited
Google Chrome, Opera, Android
GMail, Picasa, IrfanView, ImageMagik, GDAL
many others using some plug-in

Benchmark images

TopicAlbegna river estuary [Tuscany, Central Italy] Trieste railway station [Friuli Venezia Giulia, North-East Italy]
Samplealbegna
full size - uncompressed
trieste
full size - uncompressed
Short descriptionan RGB orbital scene taken from the OrbView satellite.
Resolution: 4m / pixel
Approx location: 42°26'15"N 11°11'39"E
Freely availble thanks to USGS
a Grayscale [B&W] orbital scene taken from the OrbView satellite.
Resolution: 1m / pixel
Approx location: 45°38'10"N 13°48'15"E
Freely availble thanks to USGS
Test methodologyBoth images have been compressed in lossy, destructive mode. Quality factors tested for both codecs are:
  • 90 [mild compression, high quality]
  • 75 [normal compression, good quality]
  • 60 [strong compression, normal quality]
  • 40 [very strong compression, poor quality]
  • 20 [ultra strong compression, very poor quality]
JPEG compression has been applied using GIMP 2.6
WEBP compression has been applied using the CLI tools cwebp and dwebp included into the recent libwebp 0.1.99

Please note: all the WEBP samples are actually supplied as PNG images. This is strictly required, because not all web browsers are able to visualize WEBP images.
Anyway each PNG image faithfully represents the corresponding WEBP image, and no further quality loss is introduced by this format conversion, because PNG adopts a lossless compression.

Benchmark results [compressed size]

SampleJPEG sizeWEBP sizeJPEG imageWEBP image
Albegna Q=90230 KB161 KB show show
Albegna Q=75130 KB71 KB show show
Albegna Q=6096 KB57 KB show show
Albegna Q=4060 KB42 KB show show
Albegna Q=2040 KB28 KB show show
Albegna Q=1022 KB21 KB show show
Albegna Q=0513 KB17 KB show show
Trieste Q=90374 KB330 KB show show
Trieste Q=75239 KB177 KB show show
Trieste Q=60188 KB149 KB show show
Trieste Q=40146 KB116 KB show show
Trieste Q=2095 KB80 KB show show
Trieste Q=1057 KB62 KB show show
Trieste Q=0531 KB51 KB show show

Just some useful term of comparison:

Conclusions



Last updated: 2012-07-26
Author: Alessandro Furieri
cc-by content on this site is licensed under a Creative Commons Attribution 3.0 License