Author Archives: Grant Slater

Meet Grant Slater, the OpenStreetMap Foundation’s new Senior Site Reliability Engineer

Thanks to the support of corporate donors, the OpenStreetMap Foundation has been able to hire its first employee, who is starting on 1 May 2022. Grant Slater and Guillaume Rischard, the Foundation’s chairman, sat down for a virtual chat.

Hi! Tell us about you?

Hi! I’m Grant Slater, and I’m the new Senior Site Reliability Engineer (SRE) working for the OpenStreetMap Foundation. I’m originally from South Africa, and now live in London (UK) with my wife Ingrida and our son Richard.

What do you do in OSM? Where do you like to map?

I’ve been mapping since 2006, mostly in the Southern Africa and in the United Kingdom. I have a strong interest in mapping the rail network of South Africa; holidays “back home” often involve booking railway trips across the country, with a GPS in hand.

My latest toy is an RTK GPS base station and rover. I’ll soon be mapping my neighbourhood with centimetre-level accuracy.

For the last 15 years, I’ve been part of the volunteer OpenStreetMap Operations Team who install and maintain the servers and infrastructure which runs the website and many other related services.

What are your plans for the new SRE job?

My main objective will be helping improve the reliability and security of the project’s technology and infrastructure.

One of my goals will be to improve the project’s long-term stability as we grow. OWG can’t work without volunteers, and I will be improving the Operation Team’s bus factor by also improving our processes, documentation, and by smoothing the path to onboarding new team members.

I will be helping to drive forward modernising the project’s infrastructure by reducing complexity, paying-down technical debt, and reducing our need to maintain undifferentiated heavy lifting, by tactically using Cloud and SaaS services, where suitable.

Is there anything else you’d like to say?

With time, I would like to see OpenStreetMap introduce new tools and services to improve our mappers’ access to opted-in passively collected data to improve the mappers’ ability to map and detect change.

Gamification! OpenStreetMap should always remain a fun and gratifying experience for all. We’re building an invaluable and unique dataset with far-reaching consequences for which we should be incredibly proud. Happy Mapping!

I would like to hear your feedback and suggestions, please email me

Grant gave a talk at State of the Map US (2013) – OSM Core Architecture and DevOps and is hoping to give an updated talk at State of the Map 2022 in Florence, Italy 19–21 August 2022.

Upcoming Maintenance

On Saturday 5th of July 2014 between 09:00 and 19:00 (GMT / UTC) we are moving our servers hosted by University College London to another data center.

The following services will be affected:

  • Search ( will be unavailable. *
  • Slower map updates / Reduced tile rendering capacity. (Yevaud outage)
  • OSM Foundation websites and will be unavailable.
  • Taginfo ( will be unavailable.
  • Development Server (errol) will be unavailable.
  • Some imagery services will be unavailable. (GPX Render, OS
    Streetview, OOC, AGRI, CD:NGI aerial)

Other OpenStreetMap provided services should not be affected – all of the following are expected to function normally:

  • web site will allow edits as per normal (iD or
  • API will allow map editing (using iD, JOSM, Merkaartor etc.)
  • Forum
  • trac (bug-tracker)
  • tile serving (“View The Map” & “Export”)
  • Wiki
  • mailing lists
  • subversion and git (source code repositories)

Technical: We are moving all the servers listed here to a new UCL data center. The current building is being closed soon for refurbishment. The new data center has better server racks, power feeds, cooling and faster networking.

* Searches through the website will still work – we will redirect
them to another nominatim instance temporarily.

Grant Slater
On behalf of the OpenStreetMap sysadmin team.

OpenStreetMap Enhances User Privacy

Today, OpenStreetMap has enabled encryption (SSL) to all of the website, thereby enhancing the privacy of its users.

You can now browse the site at (note the ‘https’). This means your browsing activity is secure from snooping.

OpenStreetMap stands with the Open Rights Group and the Electronic Frontier Foundation in asserting greater Internet freedom, including the right to individual privacy. With this action providing the highest quality Free/Open Data Geographic resource to everyone.

We are proud to roll this out on the same day as the “Day We Fight Back” campaign.

Other aspects of privacy around OpenStreetMap are discussed on this wiki page.

OpenStreetMap infrastructure donation – Bluehost

Thanks to generous donations and active local community members, the OpenStreetMap distributed tile delivery infrastructure continues to grow.

Two tile servers, nadder-01 and nadder-02, have been added to the OpenStreetMap tile cache network.  Based in Provo, Utah, USA, these servers provide tiles to the Americas.

Map tiles are delivered to users based on their GeoDNS location. The OpenStreetMap Foundation seeks additional distributed tile servers. If you would like to donate a tile server and hosting, please see the Tile CDN requirements page on the wiki.

tile serving geodns map

We would like to thank the BOSS team (Bluehost Open Source Solutions) and especially Jared Smith at for this generous donation to OpenStreetMap infrastructure.

The OpenStreetMap Foundation is a not-for-profit organization, formed in the UK to support the OpenStreetMap Project. It is dedicated to encouraging the growth, development and distribution of free geospatial data and to providing geospatial data for anyone to use and share. The OpenStreetMap Foundation owns and maintains the infrastructure of the OpenStreetMap project. You can support OpenStreetMap by donating to the OpenStreetMap Foundation.

New tile rendering and CartoCSS stylesheet

The default “standard” map was switched across to a new rendering server setup over the last weekend.

In addition to new hardware, the rendering server also uses the new “openstreetmap-carto” stylesheet. This is a complete re-write of the old XML stylesheet to use CartoCSS, making it easier for our cartographers to work with. The style is designed to look as similar as possible to the old XML stylesheet.

Andy Allan presented a great talk at State of the Map US conference describing the reasons for re-writing the stylesheet: Putting the Carto into OpenStreetMap Cartography

Andy Allan Stylesheets

Andy will present a follow-up at State of the Map next month.

The “openstreetmap-carto” stylesheet is maintained on github

“openstreetmap-carto” is a good base for creating custom styles, and should be much easier to work with. If you want to help improve the style, or add new features, please fork it and contribute pull requests!

Please support OSM’s server hardware fundraising drive