Same LAT or LONG: possible duplicate entries on Speed Camera POI

I take it you have never been to Phoenix. Many of the streets there are long N/S or E/W stretches of straight road. If you use a program such as http://www.itouchmap.com/latlong.html you can enter the coordinates and see you are dealing with different points on a straight road.

Your location is defined by both the latitude and longitude.

Longitude = angular distance east or west from the prime meridian.

Latitude = angular distance on a meridian north or south of the equator.

So, if you move exactly North or South, your longitude will not change but your latitude will. Hence a street that runs exactly North-South will have the same longitude for every intersection, only the latitude will change.

Jack j

Batera,

Using just the coordinates on iTouch as one of the other posters suggested I find the cameras are posted on two different freeways here in Phoenix. They are both located at 15th Avenue which runs North and South, but are separated by at least 2 miles from each other.

I am surprised there are not more duplications like you have shown because of the number of cameras here in the Valley of the Sun.

I hope this helps.

Open the redlight or speed camera (or any POI) file in Extra_POI_Editor. Then ask EPE to display the points on Google Earth (F9). Zoom in on Phoenix and you will see a bunch, many of which are lined up precisely in a row on an E-W street.

If I was geocoding those points one by one, I'm sure each would be off by several digits at 5 decimal places. Since these streets are on an exact grid for some distance, it was probably easier from an editing standpoint to establish a valid Lat or Lon for that segment and then input the other unique values. As you can see from GE, the points where the cameras are reported line up quite nicely with the intersections and roadways.

The maintainers work hard to update and verify these particular files to make them as current and as accurate as possible. Phoenix happens to be one of those places that the surveyors had few natural land features in the way when they laid out the streets and may have taken it as a personal challenge to get many of them as close to E-W and N-S as possible.

a_user: I'd like visit Phoenix one day. Haven't had a chance yet. Thanks for the link. I had been using Google Earth previously, which is not as easy as this site to find coordinates on a map. I'll start using this one from now on.

jack180: thank you for explaining the basics of latitude and longitude. I wish I knew all this when I was in the Navy driving those big ships around!

vegasbound: I see it as well. However, based on personal experience, I know that sometimes we might report the camera on the wrong location. It happened when I reported two cameras to MsPOI last week. When passing through the camera at a certain speed, I can't slow down to save the coordinate on the GPS or write down the coordinates, so when I get back home I launch Google Earth and get the coordinates of that location to the best of my memory. Well, two things happened: (1) in one of the camera locations I accidentally wrote MsPOI a 0 instead of a 3 on the LONG, which threw the site to another state, and (2) on the other site I plotted the wrong intersection on Google Earth. I entered them on my GPS and went through the cameras again, that's when I noticed they weren't flagged and found the mistakes.

TXRver: I'm not familiar with Extra POI Editor. I use the cheap Editor that came with my cheap Magellan!

Anyway, I can see now that a lot of cities out there indeed have a very flat complexion with perfectly straight streets going N-S or E-W which could explain duplicate LAT or LONG. I thought that some of the 4 cases I brought up could have been an incorrect sighting and/or report as happened to me recently. I guess not.

Cheers to all,
Claudio (batera)

Your question was probably something others were curious about as well. Glad we could clear a little of the fog.

TXRver, after replying to you, I searched for and downloaded the Extra POI Editor. It seems fun to use and definitely offers lots of options and screens that the cheap Magellan tool does not.

I'll play with it some more tonight.

Thanks for the tip.

Claudio (batera)

A_USER Thanks for the link to http://www.itouchmap.com/latlong.html

neat app.

If you already knew the answer, why ask the question.

Jack j

Jack, I believe I already answered why. I thought that it would be more probable an entry error on the POI file, then a long stretch of road N-S or E-W that was perfectly linear to have many cameras in it with the same LAT or LONG. As I wrote on my original post, I thought the second option was improbable. I learned that there are such long stretch of roads just that way over there.

Thanks for contributing to the discussion.

Claudio (batera)

Claudio (Batera),

I find very few of the camera locations in the Phoenix area are incorrect. Whoever started the project here and those that are maintaining it are doing a fantastic job considering how many locations came online quickly and how many there currently are.

Come visit Phoenix when you can, but be sure to use your GPS and drive safely here in the Valley of the Sun.

Just being curious plotted the coordinates on Google maps.Zoom in real close and it will give you a pretty good view. http://maps.google.com/maps/ms?ie=UTF8&hl=en&msa=0&msid=1142...

33.42949 -11209124

33.46186 -11209124

Distance 2.231 miles, Azimuth 0.00 degrees