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marklit

2,406 karmajoined 15 वर्ष पहले
Big Data, AI, GIS & Networking Consultant.

Author and Technical Analyst of https://tech.marksblogg.com/

Submissions

Electric aircraft makes historic flight from Sweden to Finland

yle.fi
6 points·by marklit·3 दिन पहले·0 comments

Blue Earth Bathymetry 2.0

shadedrelief.com
4 points·by marklit·4 दिन पहले·1 comments

Pyramids – GIS Utility Package

github.com
3 points·by marklit·5 दिन पहले·0 comments

Planet crisis response imagery related to the earthquakes in Venezuela

source.coop
2 points·by marklit·10 दिन पहले·0 comments

Vantor's Open Satellite Feed

tech.marksblogg.com
1 points·by marklit·11 दिन पहले·0 comments

Estonian camera headed for deep-space mission in 2028

news.err.ee
1 points·by marklit·11 दिन पहले·0 comments

Multi-temporal Sentinel-2 super-resolution by optimization

github.com
5 points·by marklit·17 दिन पहले·1 comments

Cirrus SF50 G3 Vision Jet [video]

youtube.com
3 points·by marklit·17 दिन पहले·0 comments

DuckDB Internals Part 1

greybeam.ai
480 points·by marklit·25 दिन पहले·153 comments

Bank of Estonia recommends keeping cash reserve at home

news.err.ee
3 points·by marklit·26 दिन पहले·1 comments

Optimal Seating on the Airbus A380

tech.marksblogg.com
2 points·by marklit·पिछला माह·0 comments

An open-source aircraft identification library in Python

github.com
1 points·by marklit·पिछला माह·0 comments

3D Japan

twitter.com
2 points·by marklit·पिछला माह·0 comments

Open Source Aviation Maps

tech.marksblogg.com
4 points·by marklit·पिछला माह·0 comments

Open Source Aviation Maps

tech.marksblogg.com
3 points·by marklit·पिछला माह·0 comments

Wi-Fi 8 in the Lab [video]

youtube.com
2 points·by marklit·पिछला माह·0 comments

An LLM Flies X-Plane [video]

youtube.com
1 points·by marklit·पिछला माह·0 comments

1.75B Airport Weather Observations

tech.marksblogg.com
2 points·by marklit·2 माह पहले·0 comments

The EO community probably does not need your weekend package

spectralreflectance.space
5 points·by marklit·2 माह पहले·0 comments

Three Years On: Analysing Advent's Maxar Acquisition

newsletter.terrawatchspace.com
2 points·by marklit·2 माह पहले·0 comments

comments

marklit
·3 माह पहले·discuss
Thanks for pointing that out. I'll update the post.
marklit
·3 माह पहले·discuss
I love that idea. I don't have time for anything elaborate today but I dropped two visualisations at the bottom of the post.
marklit
·3 माह पहले·discuss
141 scenes in this dataset have MP4 counterparts.
marklit
·5 माह पहले·discuss
I can't get the vector basemap to render in QGIS properly with any other projection. I love using EPSG:3301 for Europe, etc.. but loads of strange things happen. Even 4326 is an issue.
marklit
·5 माह पहले·discuss
Glad you enjoyed it.

There should be enough SQL in the blog to re-purpose extracting out the Wildberries locations and seeing where they land on top of. I've never heard of this firm before you mentioned it.

From Google:

> Citibank operates over 2,300 ATMs within more than 600 U.S. branches, with a total network of over 65,000 fee-free ATMs

So the 57,163 Citibank locations are probably a combination of their branches and ATMs.

Update: I reviewed Alltheplaces a while back, they scrape company websites for store locations. They reported 68,227 locations for Wildberries. ATP is one of the sources Overture use but they seem to use 1.55M of the records from their 19M-record dataset. https://tech.marksblogg.com/alltheplaces.html
marklit
·8 माह पहले·discuss
I'm having a hard time tracking down the OSM-specific actions around this but Australia moved 1.8M back in 2017 due to continental shifting https://www.ga.gov.au/news/news-archive/australia-officially...

The Airport in Tartu, Estonia had a navigation upgrade last year in order to help mitigate navigation jamming that's taking place in the region. https://www.eans.ee/en/uudised/tanasest-saab-tartu-lennuvalj...

Defcon had a great talk on all the different navigational systems pilots can use and a note at the end that these shouldn't be decommissioned at the rate they're experiencing atm https://www.youtube.com/watch?v=wSVdfOn737o
marklit
·9 माह पहले·discuss
From what I've seen in news reports, China has built a lot of tower blocks that are 10s of floors, rather than the 4-5-floor buildings I saw when I worked in and travelled around India.

India has ~4x the population of the US so the ratio of buildings isn't much of a surprise.
marklit
·9 माह पहले·discuss
The US has only used 25% of its land. Overture published a land use dataset a while back that could go some way to verify how much land on earth is urban, covered in forest, etc.. That might only need a single SQL statement given how they structured their data.

I have some analysis around that topic in the middle of this post: https://tech.marksblogg.com/overture-land-cover.html
marklit
·9 माह पहले·discuss
That 5 TB of data will probably be 3-400 GB in Parquet. Try and denormalise the data into a few datasets or just one dataset if you can.

DuckDB querying the data should be able to return results in milliseconds if the smaller columns are being used a better if the row-group stats can be used to answer queries.

You can host those Parquet files on a local disk or S3. A local disk might be cheaper if this is exposed to the outside world as well as giving you a price ceiling on hosting.

If you have a Parquet file with billions of records and row-groups measuring into the thousands then hosting on something like Cloudflare where there is a per-request charge could get a bit expensive if this is a popular dataset. At a minimum, DuckDB will look at the stats for each row-group for any column involved with a query. It might be cheaper just to pay for 400 GB of storage with your hosting provider.

There is a project to convert OSM to Parquet every week and we had to look into some of those issues https://github.com/osmus/layercake/issues/22
marklit
·9 माह पहले·discuss
I'm hoping to use most of this system for the next 10 years. At some point, I want to add some beefy GPUs to it when I get back into 3D again.
marklit
·9 माह पहले·discuss
A good percentage of Pakistan did this recently and removed 35% of demand off of their grid https://www.ted.com/talks/jenny_chase_solar_energy_is_even_c...
marklit
·9 माह पहले·discuss
There are ~15 GB of SAR imagery at the bottom being rendered as is from GeoTIFF files. On my 2020 MBP rendering that amount of data in QGIS would lag without building mosaics and tiles.

The Parquet pattern I'm promoting makes working across a wide variety of datasets much easier. Not every dataset is huge but being in Parquet makes it much easier to analyse across a wide variety of tooling.

In the web world, you might only have a handful of datasets that your systems produce so you can pick the format and schemes ahead of time. In the GIS world, you are forever sourcing new datasets from strangers. There are 80+ vector GIS formats supported in GDAL. Getting more people to publish to Parquet first removes a lot of ETL tasks for everyone else down the line.
marklit
·9 माह पहले·discuss
70% of daytime RGB sat imagery is covered by clouds. I'm not sure how easy it would be to spot if clouds were covering a city's lights at night.

I've only seen Maxar publish one night time image and that was of Dubai. I suspect smaller buildings in not so well lit areas could end up getting missed out.

SAR imagery would work well for seeing at night and through clouds but I'm not sure what the state of AI building footprint detection is with SAR atm.
marklit
·10 माह पहले·discuss
I haven't done any deep dives into their road data but there was ~80 GB of it, mostly from TomTom, in the August release. I think the big question would be how much overlap there is with HERE and how would the metadata compare.

TomTom did a few write ups on their contribution, this one is from 2023: https://www.tomtom.com/newsroom/behind-the-map/how-tomtom-ma...

If you have QGIS running, I did a walkthrough using the GeoParquet Downloader Plugin with the 2.75B Building dataset TUM released a few weeks ago. It can take any bounding box you have your workspace centred on and download the latest transport layers for Overture. No need for a custom URL as its one of the default data sources the plugin ships with. https://tech.marksblogg.com/building-footprints-gba.html
marklit
·10 माह पहले·discuss
Amazon, Esri, Grab, Hyundai, Meta, Microsoft, Precisely, Tripadvisor and TomTom, along with 10s of other businesses got together and offer OSM data in Parquet on S3 free of charge. You can query it surgically and run analytics on it needing only MBs of bandwidth on what is a multi-TB dataset at this point. https://tech.marksblogg.com/overture-dec-2024-update.html

If you're using ArcGIS Pro, use this plugin: https://tech.marksblogg.com/overture-maps-esri-arcgis-pro.ht...
marklit
·10 माह पहले·discuss
> primary way to get a clean-ish OSM shapefile

Shapefiles shouldn't be what you're after, Parquet can almost always do a better job unless you need to either edit something or use really advanced geometry not yet supported in Parquet.

Also, this is your best source for bulk OSM data: https://tech.marksblogg.com/overture-dec-2024-update.html

If you're using ArcGIS Pro, use this plugin: https://tech.marksblogg.com/overture-maps-esri-arcgis-pro.ht...
marklit
·10 माह पहले·discuss
I suspect web apps that "query" the GPKG files. Parquet can be queried surgically, I'm not sure if there is a way to do the same with GPKG.
marklit
·9 वर्ष पहले·discuss
Anyone care to chime in on why spot instances are now 10x on-demand instances? I've got a thread going here: https://news.ycombinator.com/item?id=14769026