Global map projections

[tenochtitlanuk]

I've just added a page to my LB site about manipulating data like city populations at given latitude and longitude to show it on a 2D screen.

It's a project I first got interested in in May '78. See Byte May '78 I finally found time for it!

See details on Global map projections

Typical output- I will be adding to the page and putting the data up asap.

[tsh73]

Nice one
I am surprised that there are that many cities of 1e6+ population.

(have you seen some data that allows to draw recognizable night stars (==approximately right), by chance?
To add star pattern on background for this thread
justbasiccom.proboards.com/thread/1097/brain-challenge-black-hole
)

[honky]

What is the volume (MB ?) of GPS data and where can we find it?

[tenochtitlanuk]

There's a zip file of city and star files at data files

Data is easily found on the web, but 2 cautions here- files in Unix form just have LF as separator, while LB/MS expect CRLF. I just run a Linux one-line command file to alter this..
And data ranges may be say -180 to 180, or 0 to 360.

I've had the star constellation demos up for quite a while at constellations Had quite a lot of fun prompted by Ray McAllister's graphics!

[honky]

Thank you for "data files", it work perfect.

[Carl Gundel]

Mar 15, 2024 9:27:18 GMT -5 tenochtitlanuk said:

There's a zip file of city and star files at data files

Data is easily found on the web, but 2 cautions here- files in Unix form just have LF as separator, while LB/MS expect CRLF. I just run a Linux one-line command file to alter this..
And data ranges may be say -180 to 180, or 0 to 360.

I've had the star constellation demos up for quite a while at constellations Had quite a lot of fun prompted by Ray McAllister's graphics!

Hmm.  The data files link doesn't work for me.

[tenochtitlanuk]

Just checked- it's working fine for me. Did you get an error message? Do the links to the web page for this and the Constellations also not work for you??

[honky]

Look in the code, you must rename the file: "City data.txt" in->: "LatLon2.txt"

[tenochtitlanuk]

Thanks honky -Yeah- sorry about the naming. Too many versions I've been playing with!

[honky]

I can't stop and continue the animation.
How and where to do?
Thank you for.

[tenochtitlanuk]

After the for/next loop has gone through all the iterations, you will find it has saved all the screens. I use the GIMP to turn these into an animated GIF- you can select the frame time interval, but other software should do the same. Then load the animation in your web-browser. I can supply info on doing this in GIMP if you haven't done animated GIFs before. I do use it a lot!

If you want to run it 'live' continuously, REM out the bmpsave line, and loop/goto the beginning of the Lo loop...

[honky]

To make ".Gif", I use "Photoscape" (free).
Thank you for your informations, I will try with it.

[Carl Gundel]

Mar 15, 2024 15:42:03 GMT -5 Carl Gundel said:

Mar 15, 2024 9:27:18 GMT -5 tenochtitlanuk said:

There's a zip file of city and star files at data files

Data is easily found on the web, but 2 cautions here- files in Unix form just have LF as separator, while LB/MS expect CRLF. I just run a Linux one-line command file to alter this..
And data ranges may be say -180 to 180, or 0 to 360.

I've had the star constellation demos up for quite a while at constellations Had quite a lot of fun prompted by Ray McAllister's graphics!

Hmm.  The data files link doesn't work for me.

The link looks like this:

http://redirect.viglink.com/?key=71fe2139a887ad501313cd8cce3053c5&subId=6923193&u=https%3A//www.diga.me.uk/dataFilesCityAndSky.zip
So, if I grab the second half of it and change the https%3A to https: then it works.

Maybe Chrome doesn't like the redirect format?

-Carl

[Carl Gundel]

I posted a link to your page on FB and people are asking for the data file. Maybe it would be good to add link(s) to your page.

Thanks again.

[tenochtitlanuk]

Copy/paste this URL directly, and don't click it as a web redirect, for sample code and datafiles in a zip file.

www.diga.me.uk/CitySky.zip

Links from the forum add all the other stuff I assume.... 'tho it works fine for my browsers...