When the asset is not inside a building
In a plant, you find an asset by its line and its room. On a street lighting or parks contract, the asset is a light pole on a street, a bench or a tree.
The companies that maintain these services usually work for a city, a water or power utility or a large property owner. And that customer almost always keeps its inventory in a geographic information system (GIS), such as QGIS or ArcGIS.
The trouble starts when the work order lives somewhere else. To send someone out, you look at the map in one tool and open the job in another. And nobody knows whether the two inventories still match.
What a GeoJSON file carries, and what it does not
GeoJSON is the most practical open format for moving an inventory between a GIS and other software. Each item carries two things:
- Its geometry: a point (a light pole), a line (a pipe or cable run) or an area (a park).
- Its attributes: the columns of the GIS table, such as the ID, type, model or installation date.
What it does not carry is the history: failures, inspections, photos or documents. That is exactly what maintenance adds.
If the customer gives you the inventory as a shapefile or KML, ask them to export it to GeoJSON from their GIS. It is a standard option and takes a minute.
The coordinate system: the decision you have to get right
The same point is written with very different numbers depending on the reference system. If the file uses one and the software reads another, your items show up in the ocean or on another continent.
- The GeoJSON standard uses longitude and latitude, in degrees.
- Local government data in the US often comes in a State Plane zone or in UTM, in feet or meters. In Spain it is usually ETRS89 with a UTM projection.
- Many web maps work in Web Mercator.
Before importing anything, ask the customer’s GIS technician which system they export in, and write it down with its EPSG code. If in doubt, ask for longitude and latitude (EPSG:4326), which is what GeoJSON expects. It is a one-minute question that saves an afternoon of errors.
An ID that identifies and a name that reads well
Of all the columns in the inventory, two matter more than the rest:
- The ID: the item’s stable identifier in the customer’s GIS, such as “LUM-04512.” It is how you recognize the item on every import and avoid duplicates.
- The name: what the technician reads, such as “Light pole · 14 Main St.” It has to make sense without opening the map.
If the inventory has no IDs, ask for them to be added before you import. A name changes; an ID never should.
From a point on the map to an item with a history
Once it is in, each point stops being a drawing and becomes an item you maintain. It has its inspections, its failures and its documents, like any piece of equipment in a plant.
- The report of a light that is out is opened on that light pole, not on “Main Street.”
- The technician sees on the map where it is and what was done to it last time.
- Under the inventory you can show aerial imagery or parcel maps, to place what has no street address.
And preventive maintenance is planned by area: the items in the same neighborhood are inspected on the same route.
Re-importing without duplicates
The inventory changes: items are installed, others are removed and positions get corrected. You need to decide which system is the master and how often you update.
- Agree on the master. Typically, the customer’s GIS for position and technical data, and your system for the maintenance history.
- Re-import by ID. What already exists gets updated and what is new gets created.
- Review what does not match before you confirm. An item with no match may be new, or an ID with a typo.
And always test with one neighborhood before loading the whole city.
Common mistakes
- Items that land in the ocean because the import used the wrong coordinate system.
- Re-importing everything every time, without IDs, and ending up with every light pole twice.
- Names without IDs, which force you to match items by hand.
- Loading thousands of items at once without first testing with a few.
- Losing the link with the customer’s GIS. Six months later, the two inventories no longer look alike.
How to tell it is working
- Work orders with the item identified, out of all the work orders on the contract.
- Items with no position, or with a position outside the contract area.
- Duplicates after each import. This should be zero.
- Time to find the item during a failure, as your technicians report it.
If you also maintain equipment indoors, see where to start an asset inventory. The method is the same: first the ID, then everything else.
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