Change coodinate system

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Anton

Change coodinate system

Post by Anton » Sun Mar 27, 2016 8:10 pm

Hello, how i can switch coordinate system to SK-42 OR PZ-90 ? my friends showed me that they were able to adjust your program accordingly, but now I have no way to ask them how they did it. Can you tell me?
https://en.wikipedia.org/wiki/SK-42_reference_system

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Re: Change coodinate system

Post by Psyberia-Support » Mon Mar 28, 2016 11:31 am

Hi,
First, you need the paid version to import coordinate systems other than the ones available by default.
Then, in the app click on the main menu button, then "Settings" and on "Location format". At the bottom of the list, click on "Import", then type the codes for those systems:
- "EPSG:4923" for PZ-90;
- "SR-ORG:7809" for SK-42.
Please validate those format with a reference point before relying on them.
Let me know if you have any issue.
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Anton

Re: Change coodinate system

Post by Anton » Tue Mar 29, 2016 7:43 am

Thx for answer, can you give link to paid version, i can't find it.

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Re: Change coodinate system

Post by Psyberia-Support » Tue Mar 29, 2016 12:42 pm

AlpineQuest is available here on Google Play.
And this feature is available for free in OfflineMaps (here on Google Play).
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Anton

Re: Change coodinate system

Post by Anton » Tue Mar 29, 2016 2:08 pm

I try use it on OffilneMaps, and have error - "Cant recognize ellipsoid krasovsky"
What i do wrong?

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Re: Change coodinate system

Post by Psyberia-Support » Tue Mar 29, 2016 6:01 pm

I've just tested both codes with the last version (2.2c) and it worked fine...
However I've changed a parameter order that may not work in older version, so you should try the import, it may work better now. What version do you use?
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Anton

Re: Change coodinate system

Post by Anton » Tue Mar 29, 2016 6:44 pm

Version 2.2c
I try PZ-90, it work fine.
But when i try SR-ORG:7809
I have first error: Cant recognize ellipsoid krasovsky
then: conversion parameter not found
and after all this the coordinates are wrong, x is negative and not correct, y simply incorrect.

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Re: Change coodinate system

Post by Psyberia-Support » Wed Mar 30, 2016 11:50 am

Ok, I don't get why you have errors when importing this coordinate system, by anyway it is not correct.

I've made further research and SK-42 is actually composed of various different projections, each one depending on the current area. Just like UTM. At least this is what I understood from this document, page 14, graphic 11 (I don't read Russian but the graphics talk). Note also that "X" is for latitude (towards north), and Y towards east.

Each "band" needs to be imported separately to work (they all have there own projection code). The complete list is here (all the codes from EPSG:2492 to EPSG:2522). The names contain the central latitude (ie "Pulkovo 1942 / Gauss-Kruger CM 57E" is for area from 54°E to 60°E, or 6° width centered on 57°E).

For example, if you are at a location with a latitude of around 56° East, then you'll need to import and use EPSG:2500 (which covert latitude from 54°E to 60°E as explained in the linked page)

I know this more complicated then classical coordinate systems, but right now this is the only way to make it work.
In order to make this work in the app for every areas just like UTM, it will require a new version.

Let me know is anything isn't clear.
Do you like AlpineQuest ? Leave a small comment on Google Play !

Anton

Re: Change coodinate system

Post by Anton » Sat Apr 02, 2016 5:32 am

Thank you very much! This solution work fine!

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