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Map Overlay position error? - NSW AU Oceania - Printable Version

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Map Overlay position error? - NSW AU Oceania - Stephen.Walker - 2014-09-16

Hello,

I have noticed on the live maps display for New South Wales - Oceania, there appears to be a position eror of around 200km.
I have referenced two stations of known location to illustrate the apparent error.

I know the position error also seems to apply to the Albury station - as the Albury station should be close to the NSW/VIC border.

I can't reference the New Zealand stations - although their detections are shown on the "New South Wales" map, the stations are of fthe map.

regards,
Stephen

(Sth Sydney 1 & 2).

RE: Map Oerlay position error? - NSW AU Oceania - David.Gamble - 2014-09-17

I have noticed the same thing.

RE: Map Oerlay position error? - NSW AU Oceania - KeriWX - 2014-09-18

My station (Kerikeri) appears to be OK for NZ, if you zoom right in on the lightningmap real time map it is a couple of km out

RE: Map Oerlay position error? - NSW AU Oceania - Stephen.Walker - 2014-09-18

(2014-09-18, 08:50)KeriWX Wrote: My station (Kerikeri) appears to be OK for NZ, if you zoom right in on the lightningmap real time map it is a couple of km out

Hi KeriWX,
thanks for the reply.

the map overlay error is on the Blitzortung 'live maps' page - specifically on the NSW page - (http://www.blitzortung.org/Webpages/index.php?lang=en&page_0=22&session=1). It isn't apparent on the Oceania map.

I havent checked lightningmaps.org to see if it the position error is visible there - I will check when we next have lightning in the area.

thanks

Stephen

RE: Map Oerlay position error? - NSW AU Oceania - Egon - 2014-09-18

Dear Stefen,

I will try to find the error.

If you see the error, then please login at blitzortung.org and look first whether thes coordinates are corrrect. These are the coordinates your stations send:

http://www.blitzortung.org/Webpages/index.php?lang=en&page=5&session=1&sort_column=user&sort_order=desc&selected_stations=874,966

If these coordinates are right then show me the image where the station is located at the wrong place. In this case we have a projection error, but I also see that the cities Melbourne and Sydney are correctly placed on the NSW page. These cities are place by the same algorithm the stations are placed.

Regards,
Egon

RE: Map Oerlay position error? - NSW AU Oceania - Ross.Wheeler - 2014-09-18

(2014-09-18, 21:42)Egon Wrote: If you see the error, then please login at blitzortung.org and look first whether thes coordinates are corrrect. These are the coordinates your stations send:

http://www.blitzortung.org/Webpages/index.php?lang=en&page=5&session=1&sort_column=user&sort_order=desc&selected_stations=874,966

If these coordinates are right then show me the image where the station is located at the wrong place. In this case we have a projection error, but I also see that the cities Melbourne and Sydney are correctly placed on the NSW page. These cities are place by the same algorithm the stations are placed.

One of the sites he's specifically quoted as being "way out" is mine (Albury) and of course he can't see what my station GPS info is.

I've just written a little tool to display my GPS data without exposing my controller to the world - so Stepfen, if you see this again, please click here to get the data!

Cheers,
RossW

RE: Map Oerlay position error? - NSW AU Oceania - Tobi - 2014-09-19

If the positions of all stations are wrong, then there's a problem with the map projection.

@Egon: The cities are already on the underlying map image, so they can't be wrong. Wink

RE: Map Oerlay position error? - NSW AU Oceania - Stephen.Walker - 2014-09-29

Hi,
Sorry for the delayed response.

Ross - thanks for the location data for your Albury station. If I apply it to the original map snapshot, it gives nominally the same error.

I haven't looked at the NSW map during storms to see if the error is still there. I will try to do this next time we have storms in the area.

regards
Stephen

RE: Map Overlay position error? - NSW AU Oceania - Michael.Sanders - 2014-10-01

Another anomaly I notice on the Oceania map, is whenever there is a strike detection from the station in Hawaii, the line to that station takes the "long-way" westerly around-the-world route. See attachment. The line heading off to the West is going to Hawaii. (The other 2 lines to the North West are going to Bangkok Shy and Phnom Phen.)

Maybe something to do with the International Date Line...?

RE: Map Oerlay position error? - NSW AU Oceania - cutty - 2014-10-01

(2014-10-01, 10:00)Michael.Sanders Wrote: Another anomaly I notice on the Oceania map, is whenever there is a strike detection from the station in Hawaii, the line to that station takes the "long-way" westerly around-the-world route. See attachment. The line heading off to the West is going to Hawaii. (The other 2 lines to the North West are going to Bangkok Shy and Phnom Phen.)

Maybe something to do with the International Date Line...?
Smile That will make "Lonesome Stan" Silversword, in Maui, smile, to know he's detecting across 3 oceans and continents...especially with his issue with the huge ELF Sub transmitter nearby. Stan, as far as I know, is the only station to actually be in 2 regions, , Oceania and North America. His Signal track to Region 3 is from the West, on the Reg 3 Map. You may be correct in that it's a "Dateline" thing and server parameters, ,... if memory serves, at least early on, his signals showing in Oceania came in from the east... so I have no real answer.. He's sitting out there by himself in the middle of the Pacific, awaiting development of the Blitzortung Buoy System, since that seems to be about the only way, so far, any group of receivers will be deployed around him. But he's keeping the faith!

Mike

RE: Map Oerlay position error? - NSW AU Oceania - Tobi - 2014-10-02

(2014-10-01, 10:00)Michael.Sanders Wrote: Maybe something to do with the International Date Line...?
Exactly. It has been fixed. Smile

RE: Map Oerlay position error? - NSW AU Oceania - Stephen.Walker - 2014-10-11

Hi,

I have just checked the NSW map - the position error is still present.
Egon, thanks for your suggestion - I have checked the position reporting from 874 - it is ok.

Also, my position on the Oceania area map is correct (harder to be precise due to scale) but the New South Wales map has an error.

I have marked the position error with orange triangles. I know the location of Sth Sydney 1, Brisbane Nth & Albury -one of RossW's stations.
Thanks Ross for the link to your GPS data. For reference, South Sydney ! should be about 10km from the 'Sydney' city marker on the map.

These stations all appear to be out by the same error. Very roughly, the error is -1.25 degrees latitude +0.5 degress longitude.

Regards,
Stephen

RE: Map Oerlay position error? - NSW AU Oceania - Ross.Wheeler - 2014-10-11

(2014-10-11, 11:25)Stephen.Walker Wrote: Thanks Ross for the link to your GPS data. For reference, South Sydney ! should be about 10km from the 'Sydney' city marker on the map.

These stations all appear to be out by the same error. Very roughly, the error is -1.25 degrees latitude +0.5 degress longitude.

OK, to add information to this:

If the "Albury" orange triangle is me, the other two stations shown "nearby" will be:
Wagga-Wagga (the next marker north-north-east of the indicated Albury location)
Corryong (the marker east-south-east of the indicated Albury location)

Both are "roughly" 100km from me (and are both my stations also). Their relative positions look right, but the offset is consistent.

RE: Map Oerlay position error? - NSW AU Oceania - Stephen.Walker - 2014-10-12

(2014-10-11, 22:26)Ross.Wheeler Wrote:
(2014-10-11, 11:25)Stephen.Walker Wrote: Thanks Ross for the link to your GPS data. For reference, South Sydney ! should be about 10km from the 'Sydney' city marker on the map.

These stations all appear to be out by the same error. Very roughly, the error is -1.25 degrees latitude +0.5 degress longitude.

OK, to add information to this:

If the "Albury" orange triangle is me, the other two stations shown "nearby" will be:
Wagga-Wagga (the next marker north-north-east of the indicated Albury location)
Corryong (the marker east-south-east of the indicated Albury location)

Both are "roughly" 100km from me (and are both my stations also). Their relative positions look right, but the offset is consistent.


Thanks Ross.

There is a lot of storm activity in NSW at the moment.
The position error is apparent if NSW maps & Oceania maps are compared.
My station is a bout 3km from the cost, but it is a fair way inland on the NSW map.

Tobi & Egon, let me know if you need anymore information on this.
regards,
Stephen

RE: Map Oerlay position error? - NSW AU Oceania - argus42 - 2014-10-13

The lightning strikes appear to be roughly in the correct position but the stations are 150 - 200 km from where they should be.

Argus42

RE: Map Oerlay position error? - NSW AU Oceania - Stephen.Walker - 2014-10-13

Hi argus42,

I agree - Ive attached 2 images of a storm passing through Sydney (Blitzortung & local weather radar). The NSW map is correctly reporting the storm locations, but the stations detecting the strikes are all showing the position error.

regards,

Stephen

RE: Map Overlay position error? - NSW AU Oceania - Egon - 2014-10-15

You are right, its corrected!

Egon

RE: Map Overlay position error? - NSW AU Oceania - Stephen.Walker - 2014-10-16

Thanks Egon.

Regards

Stephen