Autor Thema: Maximizing sat image detail  (Gelesen 313 mal)

Offline ogre_en

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Maximizing sat image detail
« am: 17 Juni 2019, 16:57:29 »
FIRST POST! Hi gang.

So thanks to a lot of reading and research on here and youtube, I can now sucessfully create amazing sat image maps for my lowrance elite ti2.
I use the google earth screenshot -> photoshop - >save as PNG file - > google earth KML file -> IMC application -> at5 files and it works perfectly.

Now i want to know how to get more detail and i think its somewhere in the photoshop process. I have an off the shelf navionics platinum + map and for the same location the zoomed in detail is better than my own, even though i am experimenting with very high res hi zoom images and the resulting at5s on my unit look more or less the same at all zoom levels regardless of the quality of the png i load into google earth pro to overlay their map.

Is there a way to save the png differently, or do anything differently, in order to get a better result on the lowrance screen? i assume so since the platinum plus looks so much better at hi / max zoom.

can sort of see it here but in person its a big difference - heres an example:

Offline gregory

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Re: Maximizing sat image detail
« Antwort #1 am: 17 Juni 2019, 19:23:49 »
To me, it looks like the source imagery used here is different.

I'm not real strong on color balancing but there are some people on this forum that are.

Friendly reminder on this thread - Restrict replies on imagery sourcing to legal sourcing methods.


Offline ogre_en

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Re: Maximizing sat image detail
« Antwort #2 am: 18 Juni 2019, 01:36:33 »
yes the source images are much different. i use sat images that show low tide conditions, otherwise id just use the navionics card. i want to make my own but match this level of resolution on the lowrance unit.

Offline gregory

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Re: Maximizing sat image detail
« Antwort #3 am: 18 Juni 2019, 16:11:15 »
Depending on the mapping, it's not uncommon to switch sources based on zoom.  It's fairly rare in the professional world to use one imagery source at zoomed in levels and zoomed out levels.  There's usually levels of transition.  There's a number of reasons for this but the main two are it becomes more difficult to downsample than upsample and images tend to lose vibrancy as they are zoomed out.

You say this is something you think you need to do with Photoshop.  Are you seeing degradation in the image at various levels (before vs after photoshop, before vs after IMC)?  In my limited experience, I know Photoshop sometimes downsamples large images in order to be able to work with them.  My thinking is you might try an uncompressed lossless format like TIFF.  Compression makes it more difficult to work in sections and lossiness makes you lose some information with every save.

Offline ogre_en

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Re: Maximizing sat image detail
« Antwort #4 am: 18 Juni 2019, 22:16:24 »
was a good idea but using a tiff vs using a png had same result on the unit screen.

in photoshop im using a 300 dpi resolution, but again, end result after "save as" png and tif is same as when i start at 72 resolution in the photoshop file.

cant seem to crack this, too bad would be so nice even if its a lot of work only need to do it one time.

any other ideas?

Offline gregory

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Re: Maximizing sat image detail
« Antwort #5 am: 18 Juni 2019, 22:37:23 »
It's out of my realm of knowledge.  I'm not too familiar with the application itself...only the theory.

It looks like there's a lot of potential answers on the internet.

Offline Fishton

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Re: Maximizing sat image detail
« Antwort #6 am: 21 Juni 2019, 09:30:44 »
Greg what is considered legal when it comes to satellite imagery?

As far as fishing chart detail goes I have resorted to capturing key areas with a drone which offers amazing detail 10x that of any satellite and the extra bonus of Elevation view which is 20x resolution of multi beam (C-Map Reveal) - See attachment below ...

Sorry to throw this in here ... Greg, any chance of the Lowrance HDS units offering further zoom capability (50ft range ring full screen) and the IMC handling more data?


Offline gregory

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Re: Maximizing sat image detail
« Antwort #7 am: 21 Juni 2019, 16:27:30 »
Illegal use of satellite data would be data outside the licensing agreement of the source.

For example, Digital Globe or Google.

Google's Term of Usage define some rules about usage:

Zitat
Don’t misuse our Services. For example, don’t interfere with our Services or try to access them using a method other than the interface and the instructions that we provide. You may use our Services only as permitted by law, including applicable export and re-export control laws and regulations. We may suspend or stop providing our Services to you if you do not comply with our terms or policies or if we are investigating suspected misconduct.

Prohibited conduct - Section 2c -
Zitat
mass download or create bulk feeds of the Content (or let anyone else do so);

Prohibited conduct - Section 2d -
Zitat
use Google Maps/Google Earth to create or augment any other mapping-related dataset (including a mapping or navigation dataset, business listings database, mailing list, or telemarketing list) for use in a service that is a substitute for, or a substantially similar service to, Google Maps/Google Earth;

On the last question, I don't control how far the raster is allowed to be used on the chartplotter.  If it were to be expanded, it would be expanded based off a company use case or a general charting improvement.

Offline TACKLEFEVER

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Re: Maximizing sat image detail
« Antwort #8 am: 21 Juni 2019, 17:53:24 »
What is legal in country A can be illegal in country B.
Therefore, we appeal to all, generally not to post descriptions or links to descriptions whose sources are not free worldwide.

Since these are very few where this is the case we need to protect all,
as soon as we can detect even the hint of a problem, and especially in cases of doubt,
we rather moderate and delete if necessary,
without that we consider this for all countries in detail and evaluate.

Also, links should not be posted to sites that refer to procedures or instructions to bypass locks, to access protected content of any kind, to help in the decryption of files, etc..
And of course no such instructions or assistance may be given here.

Specifically, we welcome it if you pay attention to this delicate topic even what you post and in doubt rather distance from the post.
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