Irish Grid projection.

[Sputnik]

Hi,

Great software. I'm hoping to roll this out to 20 - 25  Tablets. I was really hoping you could include the Irish Grid system (http://spatialreference.org/ref/epsg/29902/) for coordinate display/input. The Irish system uses a prefixed letter a little like the UK system. Is there any hope you could include this in a future version ?

Cheers.

[Sputnik]

Hi Menion,

Please consider this. I'd be willing to wait and I personally will buy 25 full versions. I know there would be hundreds of other Irish people interested. All of our maps use the Irish Grid system. So for any app here to be useful in the real world it has to include the Irish Grid. AlpineQuest does at the moment but with respect to AlpineQuest it's not a patch on what you are achieving here particularly with the POIs. Please.....

[idk]

I know this is not really the place for a discussion of that kind BUT:

What is the use/need of such a system???  :roll:  (I do not mean in Locus, but generally...)

[Sputnik]

Hi idk,

All topographic maps printed in Ireland (and the UK) use a national grid system (EPSG:29902, there is a newer system ITM but this is generally not in use yet) based on a different projection than wgs84. So basically for a Locus user to be able to refer to the real world - i.e. Look at a position on a paper map, or communicate your position to somebody who is using a paper map you need to use the local system (Ireland is broken into 25 squares, each square has a letter then an easting and northing). There is no useable wgs84 lat/lng degrees/min/sec on a paper map.

All handheld GPS units would have this facility. For Locus or any app to be useable in the real world it really needs to support local grid.

I'm keeping my fingers crossed. Locus is great. I'd love to be able to use it.

Cheers.

[Menion]

Hi Sputnik,
  what are main differences? For me it seems same as OSGB36 except modified datum parameters (modified Airy datum), are there more diffs? Have to check ..
  also I'm just curious how are you converting maps to locus? I know that one of main problems is not well wrote support for various projections. So there is need to convert maps to supported (usually SQLite) maps.

[Sputnik]

Hi Menion,

Thanks for the reply. I think they are quite similar. The Irish system just uses 1 letter as a prefix see http://goo.gl/n2eUf

There's some javascript code here showing/discussing some of the differences (Half way down the page 'Modifications for Ireland') but I think you are right its mainly the 'Modified Airy' http://goo.gl/O7tPc

Official http://osi.ie transformation booklet http://goo.gl/l2dqw

For the maps. I had some geotiffs (irish grid) I converted them with mapc2mapc (supports irish grid) to moile atlas sqlite. seems to work perfectly.

Hope that is some help, Thanks for your time and effort.

[Menion]

perfect. Seems as mapc2mapc is my savior

Thank you for info, I'll look at it during next week

[Sputnik]

Fantastic. I look forward to testing it if you manage to do it. Locus is great. Keep up the good work.

[Menion]

added, test please this version viewtopic.php?f=25&t=1250#p7349 because I have no converted map with such coordinate system grid to test

[Sputnik]

Genius! Thanks Menion. Appears to work perfectly. Will test loads more during the week. Many thanks. I'm looking forward to working with your software.

[Sputnik]

Hi Menion,

The Irish grid is working great. there is just one little thing to amend. The positions should always remain in 10 digit. i.e. M 01111 21111 at the moment Locus will drop the first 0 from an easting or northing so the position above would appear as  M 1111 21111. It would be important that the preceding 0 is preserved. I guess if the position is <10000 you could just stick a zero at the front ?

Many thanks,

[Menion]

no problem ... fixed. Release together with this feature will be probably in monday or tuesday

[Sputnik]

Cool...