Postcodes

Our system fundamentally works using postcodes. This article explains why.

What's wrong with free-form locations?

Back in the days of Yahoo Groups, we had free-form locations that people just typed. This sounds appealing. What's wrong with it? Well, several things. And a key point to remember is that these problems happened over and over again - for a certain percentage of wrong posts.

We got bad locations

1. People didn't know what to put. Some people would put in vague terms like 'Anywhere', or 'Edinburgh', or 'Can collect', or 'just round the corner from the Post Office'. Users (especially new users) can't be expected to know what kinds of locations are suitable for a Freegle group. We should help them.
2. So we did a lot of moderation of posts around vague or wrong locations. That meant bouncing posts back to users to correct them. That's very off-putting for them, and tedious for us.
3. They had to type locations. The more typing people have to do, the more user friction there is, the more people give up or make mistakes. The less typing, the better.

Even those of us around in Yahoo days tend to forget now just how much of a pain this was.

There are some solutions to getting human readable friendly lcoations, such as Google Autocomplete. But:

• The good ones cost too much, the bad ones are too bad.
• They are aimed more aimed at producing street or postal addresses, not the kind of addresses we want.
• They don't include "unofficial" locations that everyone knows and uses but aren't on maps.

Which group?

Another massive problem in Yahoo days was knowing which group to post on. We expected people to have found a group somehow, worked out (the name or reading a long description) what area each group covered, and decided which group to post on. This is a terrible user experience because it requires users (including new users) to solve complex geospatial problems in their heads. Imagine doing that if you're blind.

In some areas of the country, especially those with dense populations (no pun intended) this problem is very much worse than others. If you live in an area where you don't think it is a problem, your experience may not apply to areas where it is.

We spent a lot of time telling people they'd posted on the wrong group. We shouldn't let people get into that situation.

More precise locations

For these reasons alone, it's very useful for the system to know a more precise location. There are other advantages, which we'll see later.

Many countries have long had similar issues with postal addresses, and introduced solutions such as postcodes or zip codes. These are now extremely well-understood ways of defining a location quite precisely (roughly 92% of people know their own postcode from memory see here).

There is no international system for this.

• Latitude/longitude isn't suitable for humans.
• "Find my location" buttons are often not accurate.
• What3Words is trying to become a standard, but it is still extremely rare for people in the UK to know their W3W address by heart.

Our system asks for the postcode as the first item when someone posts. This means that we can identify a suitable default for them to post on - which means they don't have to make a complex choice, and also means that we don't have to spend time correcting wrong choices.

Friendly locations

We don't show people's full postcodes for privacy reasons - just the first part. It's still useful for many groups to have a human-readable location that people would recognise, for example in an email. This is partly an accessibility issue, since not everyone will be able to view maps.

We have a method to map postcodes to friendly locations. Briefly, we'll choose the smallest area that the postcode is inside, or the closest area if it's not inside one. This means moderators effectively have control over the locations that are in use on their group.

This mapping was set up many years ago, and if you've not looked at it recently (or at all) then you should do so - see the link above. If it looks a mess, then you can sort it out yourself or get help. It might seem intimidating, but remember that you only have to sort this out once.

Once the mapping is correct for your area, then all postcodes will be mapped to sensible locations - the problem of some people getting them wrong on posts has been removed.

Other benefits

Once we have a precise location, there are other useful things we can do:

• Show people how far away a post is, to help them decide whether it's reachable.
• Find other nearby posts they might be particularly interested in.
• Automatically show people posts based on approximate travel time.
• Generate statistics on a postcode basis, which is something that ties in to work councils and other organisations do (a lot of demographic data is postcode-based)

None of these are things you can do without locations which are accurate to around the postcode level.

TrashNothing

TrashNothing has the same problems. But as an international system it can't have a single solution. So it does a mixture of things:

• You can define the subject line format, for example to include a short location and part of a postcode
• You can forbid certain locations.
• It tries to establish a precise location (which is passed to us) and allows the user to correct it.
• Find my location and IP location.

This still leaves a fair number of posts where the location is wrong, and you will occasionally see this. You may have to ask TN users to correct their location:

To edit your post, follow the instructions at: https://help.trashnothing.com/how-do-i-edit-my-post. And once you’re editing your post, click on the map to change where the map shows or use the 'New Location' option that is part of the Location selection on the edit post page.