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Learning About the GeoTIFF File Format with a Hex Editor (2018)

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Re: Learning About the GeoTIFF File Format with a Hex Editor (2018)

#5
post #2

speaking of this, what hex editor would community recommend for examining (potentially quite large) binaries?

I haven't gotten my hands dirty with it myself yet, but Poke looks super interesting!

https://www.jemarch.net/poke

https://media.ccc.de/v/ASG2019-127-gnu-poke-an-extensible-ed...

Actually, it sounds like a fun weekend task to redo this GeoTIFF writeup in Poke :-)

Re: Learning About the GeoTIFF File Format with a Hex Editor (2018)

#6
This is a good hex editor overview, but also the part about Cloud-Optimized GeoTIFFs is quite good. In the past couple of years COGs have really revolutionized the satellite imagery industry. Even USGS has seen this is the future and publishes the official Landsat data in Cloud-Optimized GeoTIFF format [0].

I've been leveraging COGs recently to quickly bring satellite imagery into the browser for analysis [1].

[0]: https://www.usgs.gov/core-science-systems/nli/landsat/landsa...

[1]: https://www.unfolded.ai/blog/2021-04-28-raster-layer/

Re: Learning About the GeoTIFF File Format with a Hex Editor (2018)

#7
post #4

Could we build a static “Google Maps” using really big GeoTIFF files and downloading part of them with the section of a file functionality. Just like the SQLite example: https://news.ycombinator.com/item?id=27025829

I think that you meant to link to https://news.ycombinator.com/item?id=27016630 instead which was the recently posted SQLite/SQL.js/HTTP range library

And there was a specific sub-thread in the conversation that mentioned using this for maps too!

https://news.ycombinator.com/item?id=27020372

Re: Learning About the GeoTIFF File Format with a Hex Editor (2018)

#8
post #4

Could we build a static “Google Maps” using really big GeoTIFF files and downloading part of them with the section of a file functionality. Just like the SQLite example: https://news.ycombinator.com/item?id=27025829

You could, you'd just have to be wary of how large the header metadata would be. If you had a single Cloud-Optimized GeoTIFF of the world with internal tiles up to zoom 14, the header metadata could be a few MB, which wouldn't be ideal to load in every client.

Re: Learning About the GeoTIFF File Format with a Hex Editor (2018)

#9
post #4

Could we build a static “Google Maps” using really big GeoTIFF files and downloading part of them with the section of a file functionality. Just like the SQLite example: https://news.ycombinator.com/item?id=27025829

You could, you'd just have to be wary of how large the header metadata would be. If you had a single Cloud-Optimized GeoTIFF of the world with internal tiles up to zoom 14, the header metadata could be a few MB, which wouldn't be ideal to load in every client.

The posts on this topic on your site are really fascinating!

https://kylebarron.dev/blog/cog-mosaic/overview

https://kylebarron.dev/blog/cog-mosaic/naip

Re: Learning About the GeoTIFF File Format with a Hex Editor (2018)

#10

Earlier quoted context omitted.

You could, you'd just have to be wary of how large the header metadata would be. If you had a single Cloud-Optimized GeoTIFF of the world with internal tiles up to zoom 14, the header metadata could be a few MB, which wouldn't be ideal to load in every client.

The posts on this topic on your site are really fascinating! https://kylebarron.dev/blog/cog-mosaic/overview https://kylebarron.dev/blog/cog-mosaic/naip

Thanks! The text is still relevant but those demos are a little old. If you're curious these demos are from last week (using Cloud-Optimized GeoTIFFs under the hood to serve image data quickly):

- https://studio.unfolded.ai/public/9a2c5cd8-f0f0-43ce-b231-78...

- https://studio.unfolded.ai/public/96c70224-dd89-431f-ae7a-0a...

- https://studio.unfolded.ai/public/af792fd8-1990-4cdc-bf2b-99...

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