OTISS lets you divide an estate into several ‘sites‘.  A ‘site’ could be a park, a field, a groups of fields, a property, a car park – whatever you want it to be.

  • On the OTISS Map and Spreadsheet web pages, sites are used as a quick way of the viewing different parts of the estate.
  • Surveys are always carried out on a per-site basis.
  • Reports can be created for a specified site or for all the sites together.


Press the Sites button to goto the Sites webpage. This page has a table of all the sites for the estate.

  • The ? Help button provide a quick reminder of how to use these features.
  • The buttons along the top of the table are used to add new sites and manage the site maps.
  • The button icons at the start of each row allow for edit and deletion of the sites.
  • Pressing the buttons within a row will take you to the maps or surveys for that site.
  • Use the Search button and click on the column headers to search, filter and sort the table.

Each OTISS ‘site’ record includes;

  • A name and general description of the site, including notes on access arrangements.
  • Location/address information of the site and the access point.
  • Contact information (name, telephone, email) for the site manager, caretaker, warden or key holder.
  • An uploaded site plan or map in PDF, JPEG, PNG, TIFF, GeoTIFF formats – or simply use the online world maps.
    • When a site is linked to a geo-referenced map, then it (and its surveyed items) can be viewed on the map which is overlaid on top of the world map. The trees and items can be ploted using the GPS in your mobile device.
    • When a site is linked to a non geo-referenced plan (e.g. PDF), then it (and its surveyed items) can only be viewed on the plan, and not on the real-world maps. GPS cannot be used on these sites.

Tree Safety Zones

map risk zones example1

For users with the Tree Safety subscription, sites should also be used as ‘risk zones‘ as part of your Tree Safety Policy – in fact sites and zones are the same. A ‘risk zone’ could be a park, a group of streets, a school play ground, car park – whatever you want it to be. Often you may create 2 risk zones to cover a particular area – one high risk the other moderate risk.

  • Site boundaries can be drawn on the map around each risk zone and coloured appropriate to the risk level.
  • A site/zone is allocated a Risk Category of high, medium or low. The high risk category is recommended for ‘where there is frequent public access to trees‘ (e.g. in and around picnic areas, schools, children’s playgrounds, popular foot paths, car parks, or at the side of busy roads).
    map risk zones example2
  • The Inspection Period field allows you to specify the expected frequency of safety inspections for this Risk Zone, e.g. every year, every 3 years, etc. All the trees in the zone use this Inspection Period value, but you can also change an individual tree’s Inspection Period to deal with exceptional circumstances.

Further guidence on Tree Safety Policies and Risk Assessment Zones can be found in OTISS and HSE guidelines. and also in Common sense risk management of trees, National Tree Safety Group.



Site Boundaries

Site boundaries are optional polygons or lines drawn on the maps that you can use to show the extend of each site (or risk zone) within the estate. Simple sites would have a single polygon tracing the outline of the site (e.g. park, parish, field, woodland, etc), or a single line along a road or avenue of trees. More complex sites can have several polygons or lines as required. The line colour and width can be configured as part of the Site form.

Site boundaries can be created, modified and deleted on the map page (similar to ploting the other assets, trees, groups, etc).  The site boundaries and site names can be visible or hidden on the map as required – sometimes they just clutter the map when you want to focus on something else.

When a site is selected on the map or the spreadsheet pages of the website, the page is populated with

  1. All the assets/trees that are part of the surveys for the selected site, and
  2. All the other assets/trees that are geographically within the site’s boundaries – even if they are also part of another site.

Currently, the site boundaries are not displayed on the mobile survey apps.

Groups of Sites

For reporting and management purposes, it is often convenience to group several sites or risk zones togther and view the assets/trees for all these sites. Within OTISS, this is achieved using the Site Boundaries feature.

Group sites are created in the same way as the normal sites. Then an appropriate site boundary (or several distinct boundaries)  is drawn for the group site to include the required geographical areas. When the group site is selected on the map, spreadsheet pages or reports, then all the assets/trees that are geographically within the site’s boundaries are displayed.

Typically, all the surveys are created and carried out on the ‘lower level’ sites. The group sites have no surveys of their own, they are simply a management tool to represent various combinations of the lower level sites.

Note on Performance

Although there is no limit to the number of trees/items within each site, for performance reasons on the website and on the mobile survey devices or phones, it is best to restrict each site to less than 400 trees.