Comments and Suggestions
Sun, 21/03/2010 - 21:47 — matt
Please use this entry to submit your comments and suggestions about how to improve the site.
Please use this entry to submit your comments and suggestions about how to improve the site.
Comments
Post Box Types
Would it be possible to add annother page showing the post box types for people like me who don't know what they all look like.
Alternatively have pictures appear of the types when you hover the cursor over the 'Marker Key' box on the left hand side of the page.
Postbox types
Thanks for your suggestion.
On the first incarnation of PostBoxr I did have a link to this Wikipedia page, which I thought helped people differentiate between the types of boxes. I will add a link to the about page and underneath the marker key.
Searching, Radii, and Geocoding
Well, what can I say ?
There appear to be two separate errors.
First:
I've just looked at the raw data from Geocoding of the address "PE12 0BE". Google Maps gets the position spot on, but the geocoding URL gives about five possibilities, all of which are approximate and wrong !
Try it and see what I mean.
Second, the "distance" is wrong as well:
I've tried doing a PB search with PE12 0BE and I get a load of postboxen. I drew circles around some of them representing the "distance from" miles. Not only were these distances not distances from the given point, but the radii didn't intersect at all.
I have prepared a JPEG, which I will send to you.
Postboxr can not work like this.
Search
Matt - you need to improve the "Search" facility. I've just added 4 postboxes in Herne Bay, Kent, CT6 area; if I search for "Herne Bay" I get "no records". If I search for my postcode I get one box in Herne Common, which is allegedly 0.6 miles away (which I doubt), yet 3 of those I have added are closer. The ones I have added are on the map if I slide them into view.
If I search for "Beltinge, Herne Bay" it finds the ones that I have added in that village.
Searching
Well I've just tried smited01's example of Herne Bay.
Using a radius of 2mi:
a) "Herne Bay" returns "no results found"
b) Typing "Herne Bay" into a standalone GM geodecoder returns the single result 51.37149,1.12555
Typing those coordinates into Postboxr's search box, I get the correct five postboxen displayed.
WTZ is going on ?
[later]
I've tried searching in postboxr for the full postcode "PE12 0BE". I get two postboxes about 5 km from that location, even though I know there are some closer.
If I type that postcode into the geodecoder, I get 52.81425,0.09835. Typing that into postboxr gives the correct set of 20+ boxen. In both cases, I used a search radius of 2mi.
Matt, this is a SERIOUS ERROR. postboxr is unusable in this state, except for people who want to post (not search)
Can you, as a diagnostic, show the intermediate results from the geodecoder when searching, so we can see if it is a problem with the geodecoder, or with the distance-determining algorithm.
Distance calulations
For your information this is how the distances are calculated.
http://www.movable-type.co.uk/scripts/latlong.html using the Haversine formula.
Searching
I've been having the same problem since PB went live (or at least since the number of postboxen was significant).
I can't see where the fault lies: Google Maps itself works correctly and all Matt is allegedly doing is submitting a single string to GM, to get a coordinate-pair back.
I can see several reasons why this might fail in the way that we are experiencing; I don't know which, if any, are correct.
a) A postcode-lookup only returns the center of that postcode, without reference to its boundaries; the center of the postcode could be some way from where the PB are. This fault would not show up on GM. A more sensible way would be for GM to return a bounding polygon for that postcode. (The same applies for any settlement.)
b) Matt's distance-determining algorithm is not right. To do the search, you have to potentially do a pythagorean calculation between the (center of) the postcode and each-and-every PB in the database. I suspect that Matt is doing a Brute-Force calculation, rather than basing the database on tiles. Perhaps any optimisation he is doing ("don't do the square root" because it's obviously too far) is not right.
c) Google is not returning a unique match, and Matt is treating that as "no match".
Also, I've noticed that "no results found" also happens when the server is too busy or when the address/location can not be parsed.
For a casual user, the search facility (the very raison d'être) is next to useless, because of problems which we have experienced. To expect a user to have to try "Baldock", "Baldock SG7", "SG7" to get a list of PB in that town is not on. (Only one of those strings gave the right result.)
I would suggest that
a) any search radius greater than 10mi is unhelpful; no-one is going to go that far to post a letter
b) break the database up into tiles of, say 5km x 5km, with each PB going into exactly one tile (you'll need to map to OS coordinates at the point of entry, rather than recalculating it every search)
c) Get the geocoding working sensibly
d) Map the geocoding into a tile.
e) work out the pythagorean distance between that location and others in that tile and the eight surrounding tiles (tip: you don't need to do the square root bit, if you're just looking for "less than")
f) Render all those whose pythagorean distance (square of) is less than the specified radius.
Update
I'm updating my code to work with a newer version of the Google Maps API. This will solve the issues with the Geocoding. Can't give a time frame I'll post on the blog when it's live.
Thank you everyone for your feedback.
Zooming and searching
What's up with the zoom function ? For the past week, I haven't been able to zoom in (or out) to any level other than the "2 miles" scale. All I get when I scroll with the mouse wheel is some animation. Using the drag-bar at the left of the map has no effect either.
Also, searching is very erratic. Typing in a postcode such as "SG7" returns "no results found" (when I've added some in that postcode myself). More often that not, it gets stuck at the "transferring data ..." stage.
What on earth is going on ?
Richard [in SG2]
Zooming and geocoding
I've just come into the Library to use their computers, which use IE. Zooming here is the same as on my own computers: just gives a "zooming" animation, with no actual zooming.
Can you also sort out how the geocoding works: at the very least distinguish between "can't interpret location" and "no results found". "Baldock" returns "no results found", "SG7" returns "no results found". "Baldock SG7" works correctly. You can't expect casual visitors to this site to have to try various combinations to get their search parameters right !
Surely, all you're doing is passing a search string into Google Maps and getting the result from it. Why is there such a disparity between Google Maps' and postboxr's decoding of an address ?
Postcodes
Can you try doing a search with "SG6" and "SG7", please ?
SG6 returns with the correct results of the search. SG7 returns almost immediately with "no results found".
Richard [in SG2]
Geocoding
PostBoxr uses the Google Maps API Geocoder. Whatever is typed in the text field is sent to Googles' Geocoder which then returns coordinates which are then processed. I'll have a look to see if anything can be optimised.
Geocoding
Does Google's Geocoding always return a unique match ?
Surely, if you type in something ambiguous, it gives you a choice ? Google Maps does that but postboxr doesn't; I assumed that if you were getting a "non-unique match", you were treating it as a "not found".
Did you try the examples I gave ?
Also, I have 30-odd postboxen marked for deletion. Can you review these please and, if you agree, remove them. I don't make the decision to delete lightly: I am working through existing postboxen from the beginning, and I am finding tens of them which are many hundreds of meters away from where they should be.
Google Maps overlay
Is there any reason why a Google Maps "My Maps" layer from the PostBoxr .xml download could not be made available ? I'd do it myself but I'm not sure whether this wouldn't violate the CC Licence.
Advantages:
You (matt) can concentrate on the database input/edit aspect, leaving the Google Maps infrastructure to deal with the searching. Postboxr has severe troubles looking up certain locations, returning "No results found" far too often, when it simply can't get a unique match for a given location, or when it can't contact the server in a reasonable time. Also, the panning and zooming would work sensibly and the loading of markers would happen at a much more sensible speed.
People who are interested in just finding out (i.e. not being a spotter) where a PB is, can just goto Google Maps and/or GSV to find it, correlating it with other things on those services, without having to learn a new user interface.
It'll work on mobile phone browsers (currently, Postboxr doesn't work on my mini-Opera for some reason: no map)
It'll make it a bit more acceptable to Royal Mail if they can (eventually) provide a link to the GM Layer from their web site. They're more likely to provide a link to Google than to Postboxr.
Google Maps
What's happened to the maps on postboxr ? Nothing is showing, in search, browse, contribute, or edit.
Google Maps itself is working fine.
??
It's working fine for me...?
Google Maps
Tried it on three computers, three different internet connexions, all Firefox. No map, had to work manually entering the coordinates; not nice.
Started working again about a day after I reported it.
External picture hosting
How about the facility to have pictures of postboxen hosted on some other site, such as image-shack or flickr ? You've previously told me you were concerned about the file-sizes of images hosted on PostBoxr and the images get recompressed, which makes them look awful.
Of course, you could just put a hyperlink in the further_details field, but that would take up space in that field, suffer from all the weird escapings that PB does, and wouldn't be in a consistent place for people to click on.
postboxr and postbox finder
I am beginning to question the need for such a complicated entry screen.
Do we really need to enter "town/city/village" and "county" for every single postbox ? Surely this info can be derived by looking at the map of which it is a part.
All you need is "box number" and "coordinates".
The mission statement is "to help find your nearest postbox". I really don't care if my nearest postbox is in a different street, or in a different county; I'm only bothered about the closeness.
I'm currently entering about 40 new boxen a week, and I would love an API of the nature postboxr.co.uk?set="G1R;0AA;50.000;-3.000"
Similarly for the last posting times: Given that RM have now released these times, can't the database be augmented with these automatically ?
Suggestions (again!)
1. A flag which says whether the last collexion for the day has "gone", according to the last collexion times, if given. Should take account of Sundays and BHs and those boxen which have no collexion on Saturdays.
2. A standard format for specifying last collexion times, so that the above can work sensibly.
3. A new category of box "wall box in a brick pillar". I've come across a few where I don't know whether to call them a "pillar" or a "wall" box.
4. A new category of box "plastic pillar". These are made of some polycarbonate (?) and are exclusively inside other semi-public buildings, where they are not subject to the elements. Having this category will help reinforce that the box is generally not accessible unless the containing building is "open".
5. A "percentage complete" for each postcode district
6. Optional smaller search radius, like half a mile instead of 2 miles.
7. Some guidelines as to what to put in the County field for neighborhoods in city locations such as Manchester and London
8. (my favorite boeuf) Have the search area and radius change as the map is panned/zoomed.
9. A method of showing "this is a very approximate location" for a given postbox, so that people can enter them straight from the RM .pdf file, and have someone come along later and get the exact location.
10. A banner showing latest-entered postboxen (and by whom)
11. A banner showing that "we need more volunteers to do district XX99"
12. Now google streetview has
12. Now google streetview has went online, is it possible to have a button to jump to the streetview of a postbox's location - pop it up in a separate window? I know the direction will be impossible to do automatically, you'd have to spin round 360, but this could possibly be refined by a user if they're bothered enough, and it'll be a good way to see if a postbox is actually there (well, at the date when the google car went past at least)
Streetview
I uploaded a few hundred postboxen to "My Maps" and streetview manages to get the direction correct 90% of the time, assuming the position of the postbox is correct. GSV uses the center-line of the road and postboxen are rarely in the center of the road. The simple trignometry used by GSV seems to do its job reasonably well in determining direction.
However, there seems to be a terrible mismatch generally between the 3D and 2D worlds of Google Maps. The marker in streetview almost never matches the position in the 2D world; it seems to have terrible difficulty determining perspective. This is not a fault of postboxr; it's a weakness of GM and GSV.