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The smallest 256x256 single-color PNG file, and where you've seen it (2015)

mjt.me.uk

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Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#11

Post by djbusby »

im3w1l wrote: post #8
softgrow wrote: post #5

Convert to svg maybe? For OpenStreetMap 136 bytes http://www.w3.org/2000/svg " width="256" height="256" viewBox="0 0 256 256">

The png is only 103 bytes though. Btw your svg can be decreased by changing viewBox to 0 0 1 1, and also by changing the path to a circle (implicitly positioned at 0, 0)

Doesn't the SVG scale better? I sure hope so.

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#12

Post by easrng »

lostgame wrote: post #6
softgrow wrote: post #5

Convert to svg maybe? For OpenStreetMap 136 bytes http://www.w3.org/2000/svg " width="256" height="256" viewBox="0 0 256 256">

But the PNG provided was 103 bytes :3 Also - pardon my ignorance, this may be a dumb question, is SVG universally supported in browsers these days? I’m not big up on image standards.

Yes, it's everywhere.

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#13

Post by RKearney »

lostgame wrote: post #6
softgrow wrote: post #5

Convert to svg maybe? For OpenStreetMap 136 bytes http://www.w3.org/2000/svg " width="256" height="256" viewBox="0 0 256 256">

But the PNG provided was 103 bytes :3 Also - pardon my ignorance, this may be a dumb question, is SVG universally supported in browsers these days? I’m not big up on image standards.

Yes

https://caniuse.com/?search=svg

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#14

Post by rbut »

moron4hire wrote: post #10
im3w1l wrote: post #8

Earlier quoted context omitted.

The png is only 103 bytes though. Btw your svg can be decreased by changing viewBox to 0 0 1 1, and also by changing the path to a circle (implicitly positioned at 0, 0)

The SVG could also be served with gzip compression.

  >>> len(''.encode('zip'))
  122
Gzipping doesn't save much.

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#16

Post by danielheath »

tppiotrowski wrote: post #3

One thing I've wondered about are size savings for DEM tiles. Typically elevation values are encoded in RGB values giving a resolution down to fractions of an inch [1]. This seems like overkill. With an elevation range from 0 - 8848 meters (Mt everest), you can use just 2 bytes and get an accuracy down to .2 meters. That seems plenty for many uses. Does anybody know if there's a PNG16 format where you can reduce the…

I’d suggest jpeg; lossy compression over the full precision data will get you to your target bit rate trivially.

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#17

Post by geenew »

danielheath wrote: post #16
tppiotrowski wrote: post #3

One thing I've wondered about are size savings for DEM tiles. Typically elevation values are encoded in RGB values giving a resolution down to fractions of an inch [1]. This seems like overkill. With an elevation range from 0 - 8848 meters (Mt everest), you can use just 2 bytes and get an accuracy down to .2 meters. That seems plenty for many uses. Does anybody know if there's a PNG16 format where you can reduce the…

I’d suggest jpeg; lossy compression over the full precision data will get you to your target bit rate trivially.

People get funny about accuracy in maps. Being able to specify accuracy, even a limited accuracy, is worth a lot. Saving bytes by reducing specified accuracy is in a lot of use-cases better than saving bytes by fuzzing data.

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#18

Post by tristanc »

tppiotrowski wrote: post #3

One thing I've wondered about are size savings for DEM tiles. Typically elevation values are encoded in RGB values giving a resolution down to fractions of an inch [1]. This seems like overkill. With an elevation range from 0 - 8848 meters (Mt everest), you can use just 2 bytes and get an accuracy down to .2 meters. That seems plenty for many uses. Does anybody know if there's a PNG16 format where you can reduce the…

The PNG format already allows grayscale 16bits / channel images. I regularly use this when rendering out depth maps from blender and ffmpeg seems to handle reading from these PNGs just fine (detecting the gray16 pixel format).

However I don’t know of any DEM tile apis that provide these sorts of PNGs but it sounds like a fun project!

Edit: I found this StackExchange post which shows how to generate 16-bit PNGs with gdal https://gis.stackexchange.com/questions/246934/translating-g...

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#19

Post by mynameisvlad »

djbusby wrote: post #11
im3w1l wrote: post #8

Earlier quoted context omitted.

The png is only 103 bytes though. Btw your svg can be decreased by changing viewBox to 0 0 1 1, and also by changing the path to a circle (implicitly positioned at 0, 0)

Doesn't the SVG scale better? I sure hope so.

For a single color? I don't think it really matters. It's all inherently lossless.

Re: The smallest 256x256 single-color PNG file, and where you've seen it (2015)

#20

Post by zamadatix »

djbusby wrote: post #11
im3w1l wrote: post #8

Earlier quoted context omitted.

The png is only 103 bytes though. Btw your svg can be decreased by changing viewBox to 0 0 1 1, and also by changing the path to a circle (implicitly positioned at 0, 0)

Doesn't the SVG scale better? I sure hope so.

For a solid color block it doesn't really matter. For the rest of the map sure, Google Maps in normal mode (instead of classic as in the article) is vector rendering based.
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