Home PageFacebookRSS News Feed
PocketGPS
Web
Read the current newsletter! Weekly
Newsletter
SatNav,GPS,Navigation
MacFixer, the iPhone, iPod, and iPad specialists
Pocket GPS World - SatNavs | GPS | Speed Cameras: Forums

Pocket GPS World :: View topic - Motarola Moto g and CamerAlert volume!
 Forum FAQForum FAQ   SearchSearch   UsergroupsUsergroups   ProfileProfile   Log in for private messagesLog in for private messages   Log inLog in 

Motarola Moto g and CamerAlert volume!
Goto page Previous  1, 2
 
Post new topic   Reply to topic    Pocket GPS World Forum Index -> CamerAlert on Android
View previous topic :: View next topic  
Author Message
M8TJT
The Other Tired Old Man
The Other Tired Old Man


Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK

PostPosted: Tue Feb 03, 2015 3:18 pm    Post subject: Reply with quote

@Howard.
It seems like your settings should not give too many false alerts, although having the ignore direction set would have increased them as you would get alerts for cams trapping in the other direction.

I'm not sure, but I think that the ignore direction, if set on, still takes into account your cone etc. settings so should only alert if you are travelling in the direction that the cam is set to trap to AND in the opposite direction. I don't think it works on a xx second circular radius, but I could be wrong.

Here's a recent example of what goes on 'behind the scenes' by the aforementioned unpaid volunteers . Im sure that the poster will not mind me quoting him in open forum, but I'll delete it if he does.
Quote:
A34/A4130 Milton Interchange, near Didcot, Oxfordshire

The following have all been submitted by Xxxx and me via CamerAlert:

South East direction

Add new Average camera (MY #5) at Lat:51.629711 Lon:-1.311059 Speed 70, Heading 157, This side.
Add new Average camera (MY #6) at Lat:51.621639 Lon:-1.305464 Speed 70, Heading 156, This side.

North West direction

Add new Average camera (MY #7) at Lat:51.603924 Lon:-1.2813 Speed 70, Heading 339, This side.
Add new Average camera (MY #8) at Lat:51.612946 Lon:-1.292055 Speed 70, Heading 310, This side.
Add new Average camera (MY #9) at Lat:51.616268 Lon:-1.298853 Speed 70, Heading 308, This side.
Add new Average camera (MY #10) at Lat:51.619713 Lon:-1.304276 Speed 70, Heading 331, This side.

Info for MaFt and fellow verifiers:

1. Xxxxx and I unexpectedly came across the SPECS system whilst travelling SE, I captured two SPECS but missed two. On the return trip, i.e. NW, we were ready for them so Xxxxxx, who was passenger, was able to capture all four on the A34 in NW direction.

2. There are two more SPECS in the SE direction of the A34 that need to be caught.

3. There are junction END SPECS (and presumably START SPECS) that need capturing.

4. There is are major "improvements" being done to the junction's roundabout (turning it into a hamburger layout).

5. Speed limit is currently 70mph on A34 but when roadworks start (sign stated 26 January 2015) there were 50mph and 40mph signs ready for use. The website even mentions 30mph Shocked! But until it starts we don't know. Will have to wait for submissions when it starts.

6. SPECS will be long term Temporary ones as Anticipated End Date\Time is 21 February 2016.

@bmuskett. I'll go along with that. Laughing
Back to top
View user's profile Send private message
DennisN
Tired Old Man
Tired Old Man


Joined: Feb 27, 2006
Posts: 14871
Location: Keynsham

PostPosted: Tue Feb 03, 2015 8:16 pm    Post subject: Re: Thats interesting Reply with quote

hwalker1 wrote:
It gives the appearance of a professionally run one
[snip]

My cone is set at 23 degrees and the Direction Difference at 13 degrees,
[snip]

my set range of 40 seconds at 70MPH

I'm no expert, so the following may well be absolute drivel, but try it on for size just to humour me.

Cone 23 degrees - is that at one side, 12 degrees off to the side?

Direction Difference 13 degrees - would that imply that a camera at the extreme side (12 degrees) will register if it is aimed 13 degrees off that direction?

Would that add up to a camera pointing say 24 degrees away from your direction?

Range of 40 seconds at 70mph - would that be a distance of approx 1,365 yards? Or three quarters of a mile away?

Would that explain why I get warned of a 30mph camera half a mile off the M4 at Reading?

I could actually believe that, if only I had any confidence in my logic and maths - logic being that the Range Distance is "time to camera" at the speed I'm travelling (70mph), NOT the speed at which the camera is set to trap, so a 30mph camera warns at whatever distance my speed controls the range.

I think. Smile
_________________
Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!
Back to top
View user's profile Send private message
M8TJT
The Other Tired Old Man
The Other Tired Old Man


Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK

PostPosted: Tue Feb 03, 2015 10:30 pm    Post subject: Re: Thats interesting Reply with quote

I understand it a little different to you Dennis.
Quote:
Would that add up to a camera pointing say 24 degrees away from your direction?
NO.

Lets say your cone is set to 24 degrees, this means that the camera must be less than 12 degrees to either side of your direction of travel i.e. pretty much straight ahead of you. If the camera is outside this limit CA will not alert.

Now take direction difference of 24 degrees and a camera on an overbridge. Assume your heading is due North (0 degrees) and the camera is trapping on the East/West bearing, then the direction difference is 90 degrees, so although the camera is well within your cone acceptance angle, it won't alert because the direction difference is too great.
But of course it will alert if the camera heading is given as 0 degrees. If the camera heading has been wrongly entered into the database as 15 degrees, it won't alert, as the direction difference is now greater than your setting of +- 12 degrees.

I think that the OP's apparently high 'false alarm' rate is high because he had 'ignore direction' set. I'm not certain but the name implies that so long as the camera is in your cone, it will alert, regardless of the direction the camera is 'pointing'. In this case, the camera on the aforementioned overbridge trapping East/West would alert.

A combination of a fairly tight 'cone' and 'direction difference' should (in theory) suppress a lot of real false alarms, but cameras 'around corners' might be suppressed as your heading and the camera trap 'heading' may be greater than your 'direction difference' setting. i.e. if the camera is just after a 15 degree bend, CA will not detect it until you round the bend enough so that your heading is within 12 degrees of the camera heading, which may or may not be too late, especially for a mobile. (All the above assumes that you have set both angles to 24 degrees)

There are also a lot of variable speed cams on at least one of the routes that the OP mentioned, all of them trapping his direction of travel, so he will get a lot of alerts because there are a lot of cams.

As to the 30MPH cams on a M'way. There are none that I can find on his routes, but there are a few close to the M'way on minor roads which might be the cause especially with 'ignore direction' set. But certainly not enough to cause a 30MPH alert every 20 yards, although I think that the OP has pretty much admitted that hi might have exaggerated a bit on that one.
Back to top
View user's profile Send private message
DennisN
Tired Old Man
Tired Old Man


Joined: Feb 27, 2006
Posts: 14871
Location: Keynsham

PostPosted: Wed Feb 04, 2015 9:18 am    Post subject: Re: Thats interesting Reply with quote

M8TJT wrote:
I understand it a little different to you Dennis.
Quote:
Would that add up to a camera pointing say 24 degrees away from your direction?
NO.

Why not?

Allow a different example for my small mind.

I'm travelling on heading 100 degrees. My cone is 24 degrees, so the look ahead sweep covers an arc from 88 to 112 degrees. If I'm right about variance, a 20 degree variance will accept a camera at 112 degrees, pointing at 122 degrees.

I didn't design CamerAlert so I could well be wrong about that 122 degree camera, maybe it has to be pointing only at 112.

But my VERY important point is the Distance Time. I must surely be right in assuming that the distance time is governed by the vehicle speed, not the camera speed (otherwise you could be warned at a distance too short to slow down before hitting the camera). So at 70mph, the outreach distance is about 1,365 yards - well over three quarters of a mile. Taken to ridiculous lengths, if I set my warning distance time to two and a half hours, I'll be warned about that nasty camera in London. So false alarms are pretty much inevitable if CamerAlert is to be any good. Remember, for the PND version, we recommend settings of the camera speed times 10 to give 20 seconds warning. It's inaccurate because we do it at the camera speed, not the vehicle speed, but it's a pretty good rule of thumb.

So any camera within the cone/variance/distance parameters will alert.

So there. And I wish I had never started this, just because I react to anybody criticising CamerAlert, which I have admired ever since it was given to us (and is the SOLE reason why I bought an iPhone).
_________________
Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!
Back to top
View user's profile Send private message
M8TJT
The Other Tired Old Man
The Other Tired Old Man


Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK

PostPosted: Wed Feb 04, 2015 11:05 am    Post subject: Re: Thats interesting Reply with quote

DennisN wrote:
I'm travelling on heading 100 degrees. My cone is 24 degrees, so the look ahead sweep covers an arc from 88 to 112 degrees.
Agreed
Quote:
If I'm right about variance, a 20 degree variance will accept a camera at 112 degrees, pointing at 122 degrees.
No, it has to be pointing within your direction difference angle. So if we assume that you have set that to 20 degrees (+-10) it will alert only if the cam is pointing between 90 and 110, so your 112 cam will not alert even though it is within your 'look ahead' cone of 88 to 112
Quote:

But my VERY important point is the Distance Time. I must surely be right in assuming that the distance time is governed by the vehicle speed, not the camera speed (otherwise you could be warned at a distance too short to slow down before hitting the camera). So at 70mph, the outreach distance is about 1,365 yards - well over three quarters of a mile. Taken to ridiculous lengths, if I set my warning distance time to two and a half hours, I'll be warned about that nasty camera in London. So false alarms are pretty much inevitable ....
Agreed, but the cam must still fall within the 'look ahead cone and the direction difference parameters
Quote:
Remember, for the PND version, we recommend settings of the camera speed times 10 to give 20 seconds warning. It's inaccurate because we do it at the camera speed, not the vehicle speed, but it's a pretty good rule of thumb.So any camera within the cone/variance/distance parameters will alert.
Is there a CA for PND?Settings like this will give you a constant distance, not a constant time (but not on CA)

Quote:
So there. And I wish I had never started this, just because I react to anybody criticising CamerAlert, which I have admired ever since it was given to us (and is the SOLE reason why I bought an iPhone).
Agreed, but for iThing, read Android

As per what you intimated, the OP could also reduce his warning time, and as he doesn't seem too interested in mobiles, shorten it considerably, 15 -20 seconds should be enough to check and adjust your speed in necessary for a fixed cam.

Of course, I do accept that my interpretation of the parameters could be wrong and it would be good if lutz would confirm or deny this.
Back to top
View user's profile Send private message
DennisN
Tired Old Man
Tired Old Man


Joined: Feb 27, 2006
Posts: 14871
Location: Keynsham

PostPosted: Wed Feb 04, 2015 11:41 am    Post subject: Re: Thats interesting Reply with quote

M8TJT wrote:
Is there a CA for PND?

Yes there is - perhaps before your time, but we used to download a zip file, unzip it and install it on our TomToms, Garmins and stuff. I do believe some people still don't have iThings and aThings, so they have a funny lump of a thing which sort of clings to their windscreens and somehow tells them how to get from A to B. Laughing
_________________
Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!
Back to top
View user's profile Send private message
M8TJT
The Other Tired Old Man
The Other Tired Old Man


Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK

PostPosted: Wed Feb 04, 2015 11:44 am    Post subject: Reply with quote

Quote:
perhaps before your time
You're less than two months older than me on the forum Dennis Not Worthy didn't know that! (PNDs)
Back to top
View user's profile Send private message
hwalker1
Occasional Visitor


Joined: Jul 02, 2007
Posts: 21
Location: UK

PostPosted: Wed Feb 04, 2015 2:44 pm    Post subject: Re: Thats interesting Reply with quote

M8TJT wrote:


As per what you intimated, the OP could also reduce his warning time, and as he doesn't seem too interested in mobiles, shorten it considerably, 15 -20 seconds should be enough to check and adjust your speed in necessary for a fixed cam.

Of course, I do accept that my interpretation of the parameters could be wrong and it would be good if lutz would confirm or deny this.


As the OP concerned, all this is very interesting. I was informed that many cameras, especially those on the top of a rise can have a range exceeding 1000 yards. Which is why I set the time to camera at 40 seconds, having done the same calculation as Dennis. If fixed cameras don't need that distance then I will change it. I only use the system on motorways as I take great care never to exceed the speed limit on normal roads. However, on motorways I occasionally do so as the 70 limit is somewhat slow compared with most of Europe.
Back to top
View user's profile Send private message
M8TJT
The Other Tired Old Man
The Other Tired Old Man


Joined: Apr 04, 2006
Posts: 10118
Location: Bexhill, South Sussex, UK

PostPosted: Wed Feb 04, 2015 3:17 pm    Post subject: Reply with quote

The LTI 20-20 has a maximum display range of 999 metres (a little over 1000yds) and as a handheld, I suspect that It and its tripod mounted pals are actually used at a much shorter range than this.
Fixed cameras only work over a short range (several 10s of yards) Gatso type, after you have passed them and Truvelo type a short distance before you get to them.
But having said that, you are right in being concerned about the much longer range of the laser based mobile cameras. But whether you need 1,400 yards (40 sec at 70) warning is debateable.
Back to top
View user's profile Send private message
DennisN
Tired Old Man
Tired Old Man


Joined: Feb 27, 2006
Posts: 14871
Location: Keynsham

PostPosted: Wed Feb 04, 2015 7:28 pm    Post subject: Reply with quote

Before I was granted the exalted status of an unpaid Verifier, I used to delete all 70mph cameras from my copy of the downloaded database (on my old fashioned PND Very Happy ), because that's the maximum speed limit which we should all know, so there's no excuse for exceeding it, so I don't, because I'm a goody-two-shoes.

It won't be just on the brow of hills, it'll be far-seeing from a motorway overbridge.
_________________
Dennis

If it tastes good - it's fattening.

Two of them are obesiting!!
Back to top
View user's profile Send private message







Posted: Today    Post subject: Pocket GPS Advertising

Back to top
Display posts from previous:   
Post new topic   Reply to topic    Pocket GPS World Forum Index -> CamerAlert on Android All times are GMT + 1 Hour
Goto page Previous  1, 2
Page 2 of 2

 
Jump to:  
You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum

Powered by phpBB 2.0.11 © 2001 phpBB Group
phpBB port v2.1 based on Tom Nitzschner's phpbb2.0.6 upgraded to phpBB 2.0.4 standalone was developed and tested by:
ArtificialIntel, ChatServ, mikem,
sixonetonoffun and Paul Laudanski (aka Zhen-Xjell).

Version 2.1 by Nuke Cops 2003 http://www.nukecops.com

Make a Donation



CamerAlert Database

Click here for the PocketGPSWorld.com Speed Camera Database

Download Speed Camera Database
20.065 (29 Jun 22)



WORLDWIDE SPEED CAMERA SPOTTERS WANTED!

Click here to submit camera positions to the PocketGPSWorld.com Speed Camera Database


12mth Subscriber memberships awarded every week for verified new camera reports!

Submit Speed Camera Locations Now


CamerAlert Apps



iOS QR Code






Android QR Code







Terms & Privacy


GPS Shopping