Help:Filter

Restricting Trigpoint Types

The problem

Not all trigpoints are the familiar pillars that all walkers will be familiar with. In fact the majority of the stations used by the OS, both historically for the 1936 retriangulation, and more recently for the Passive Station Database, are smaller marks, such as Bolts and Blocks. In addition, many of the stations used for triangulation were not installed by the OS at all, but are simply various flagpoles, towers, vanes etc, which were used as Intersected Stations.

Although all of the marks used by the OS for triangulation are included in the TrigpointingUK database, we do recognise that many of our users are mainly interested in bagging pillars. Others, possibly from a geocaching background, may be interested in finding "hidden treasures" such as Rivets and Berntsens, but are not interested in finding a random church spire which the OS once made a sighting of. For these people, it is possible to restrict which types of trigpoint appear in the search results.

In the Android app

In the "Nearest" list, select "Filter" from the menu. The dropdown selection button will allow you to select various types of trigpoint. NB "passive types" is a misnomer, dating back to when the only minor survey marks were those from the Passive Station Database. The minor marks from the 1936 retriangulation are included here, even if they were not resurveyed for the PSD.

On the website

In your [/mytrigs/preferences.php Preferences page], you can select the types of trigpoints you are interested in, from the "Restrict trigpoint searches to" dropdown. By default, only Irish trigpoints, benchmarks and other oddities are excluded. NB the filtering is not quite the same as on the Android app. On the website, major structures such as Curry Stools are included alongside FBMs, whereas on the Android app, anything which isn't a pillar is categorised as a minor "passive type" of station.

Bugs, features and limitations

• The Quick Search feature in the header, and any other TrigTools functionality, is not affected by this filter. Only the main search form, home coordinate searches, nearby trigs etc currently honour your preferences.
• The setting only affects new searches. Previous searches, listed under My Searches, are not affected.
• Dots for unfound trigs in the maps do not currently honour this preference. Eg [1]
• You can explicitly overide this preference, by selecting a Physical Type in the search form.