Web GIS portals: what they do and when you need one

Many organisations keep their land and asset information in several places at once: a spreadsheet of properties, a folder of scanned plans, a CAD drawing on one computer and a map printed on the office wall. Each copy is updated at a different time, so nobody is quite sure which one is right.

A web GIS (a geographic information system you use in a web browser) brings those pieces together. The map becomes the way in: click a stand, a pipe or a field, and you see its records, documents and history.

What a web GIS usually includes

• A map viewer with base maps (streets or imagery) and your own layers on top — parcels, buildings, roads, water lines or field boundaries.
• Records linked to the map — owner, status, dates, measurements and notes for each feature.
• Search by name, number or address, so people can find a stand or asset without knowing where it is.
• Documents such as survey diagrams, photos and approvals attached to the feature they belong to.
• Users and permissions, so each person sees and edits only what their role allows.
• Exports to spreadsheets, PDF maps and GIS formats for consultants and authorities.

Signs you may need one

1. Several people ask the same "where is it and what is its status?" questions every week.
2. Field teams work from printed maps that are out of date by the time they reach site.
3. Records and plans disagree, and checking them takes days.
4. You report regularly to a board, a council or a funder, and building the report is manual.
5. You already have GIS data, but only one person can open it.

How a project normally runs

1. Discovery — what questions the system must answer, who will use it and what data already exists.
2. Data clean-up — existing spreadsheets, drawings and maps are checked, corrected and put on one coordinate system.
3. First version — a working portal with the most important layers, tested by a few real users.
4. Training and handover — short sessions for each type of user, with written guides.
5. Improvements — new layers, reports or forms added as the team uses it.

Things to decide early

• Who owns the data and who is allowed to change it.
• Where it is hosted — on your own server, or on a hosted service — and how it is backed up.
• Which coordinate system your surveys and maps use, so new data lines up with old.
• How people will use it in the field, including with a weak or no mobile connection.

A small, well-used portal is worth more than a large one that nobody opens. Start with the questions people ask most, and grow from there.