While editing the next edition of WeeklyOSM, I stumbled upon a fascinating case study that caught my full attention.

A certain team, responding to a certain request, set out to display a mobile device’s geolocation on a map—completely offline, without any network access.

Their initial approach? Crawling OpenStreetMap tile images one by one and storing them locally.

It didn’t take long before they hit a wall: the data size exploded, and keeping the tiles up-to-date turned into a maintenance nightmare. Sensibly, they scrapped that plan.

Next, they evaluated two open-source tools: tileserver-gl (JavaScript) and mbtileserver (Go).

In the end, they opted for mbtileserver, citing Go’s “security” over JavaScript. I still don’t fully grasp that reasoning (somehow, it involves a decision between verifying their own source code and verifying the entire JavaScript interpreter), and I even asked them in the comments section. But for now, let’s accept that as a given and move on.

After choosing mbtileserver, they needed MBTiles files to serve. Eventually, they discovered tilemaker, a tool that converts .osm.pbf files into .mbtiles.

They successfully tested it on a small area. Encouraged, they moved on to larger datasets. Then came the pain.

“…half an hour passes, and we experience a computer freeze as all the RAM runs out.”

Their machine couldn’t handle the memory load. So they requested a beefy VM—256 GB of RAM—and tried again. Still no luck.

That’s when they discovered tilemaker’s --store option, which dumps intermediate stages to disk instead of holding everything in RAM. That tweak made it work.

Creating an offline, custom OSM map has been my white whale for years. So I decided to replicate their setup on my own desktop.

I began with installing mbtileserver. That’s when I hit this cryptic error:

cc1.exe: sorry, unimplemented: 64-bit mode not compiled in

According to StackOverflow, the issue stemmed from a broken GCC toolchain. The fix? Replace it with TDM-GCC. That worked.

Next, I needed an .mbtiles file to test.

The BBBike Extract Service came to the rescue—letting me select a custom region. I grabbed one for my hometown and placed it in the required tilesets/ directory.

Running mbtileserver… and it crashed.

Apparently, this kind of crash typically happens when Go calls external C code and something goes wrong—like a segmentation fault. Likely, this server-side tool hasn’t been stress-tested on Windows desktops like mine.

As a last resort, I turned to the JavaScript-based tileserver-gl.

The trick is to download the sample ZIP file (which contains a config file, style sheet, and a sample Zurich MBTiles file), then replace the Zurich MBTiles file with my own hometown MBTiles file that I just extracted from the BBBike extract service.

It started—but with missing text labels.

Even worse, the server would occasionally exit with no log at all.

After some digging, I found others had experienced similar issues—again, only on Windows.

Despite the original team’s success, I hit too many roadblocks—most of them likely tied to running server software in a desktop Windows environment. Their success probably hinged on using a properly configured server environment.

Someday, with access to a dedicated Linux VM, I’ll try again. Maybe.

Quick Overview/Summary

It’s been a year since my last diary entry on this, and I haven’t done too much (I don’t think) in that timeframe. The GIF below should give a good idea of the progress made. Unfortunately, a couple of the changes made in the bottom left corner haven’t been rendered yet.

What’s changed?

I’m still pushing through and adding buildings, or adjusting existing ones. There does seem to be someone else working here every now and then, as I had some of my changes deleted/modified (although I’m not sure of the reason, as the changeset description is not great).

More recently, I have been trying to add in more landuse=* as there is next to none currently. This is still a challenge, though, as so much has changed in 7 years that you’d need an on-the-ground survey or a local to confirm if certain buildings are shops or not.

Plan Going Forward

I want to try to get a couple more “big buildings” (e.g., shops or other POIs) added, as it breaks up the constant adding of odd-shaped houses. Having said that, I still find the whole process very therapeutic and immensely satisfying.

I have a craze for adding addresses to OSM. Unfortunately, in Delhi it is ridiculously hard to find a place with addresses properly displayed on the front. If you come across a house with no nameplate on it, you can be almost sure to not guess the correct house number.

This irks me a lot. So, I have decided to look for guide maps made by the locals while travelling around the city, and use those to map the neighbourhoods. I have got some nice pictures, which I have uploaded to my commons profile.

Here’s one I recently clicked. The amount of detail really supplements my survey a lot.

品牌內容細節有錯誤或修正需求， 在name suggestion index的Github修改， 可直接修改儲存為Fork分支，提issue後待審核即會更正。

品牌列表源資料庫

Jetzt ist klar: die letzten vier Blog-Einträge werden automatisiert angezeigt. Weshalb auch immer das sein muss …

ist Latein und bedeutet: der fünfte

Ja mei

Nur um mal zu schauen, wieviele Einträge im Profil ausgebreitet werden.

Warum erscheint der letzte Blog-Eintrag automatisch, wenn man alle Blog-Einträge doch aufrufen kann, wenn man daran interessiert ist?

Hat jeder oft mehrere Jahre alter letzter Eintrag noch Relevanz?

Wieso hat man wie auch bei der Aktivitätsdarstellung keine Möglichkeit, selbst festzulegen, ob man das will? Im Forum war die Mehrheit für eine solche selbstbestimmte Lösung. Aber sowas interessiert die DWG ja nicht.

⚠🚧 Work in Progress 🚧

⚠🚧 Çalışma Devam Ediyor 🚧

Following mobilization of volunteers and OSm newbies at Benue State University to kick-start a new chapter and team of Unique Mappers to drive Map Nigeria Mapathon project and the Makurdi on going project .We had a training for newbies. More than 20 newbies has been mobilized and signed up to OSM. These include William Hundu, the Team Coordinator, Lucas, Glory,Shater ,Jacob an others After the virtual meeting ,I hope to travel to Makurdi for in-person training and MOU with the University and Unique Mappers Network,Nigeria

Also .we are planning for stakeholders workshop for data use cases

For many years, I’ve used pre-made Garmin maps from the internet on my devices while hiking, running, or mountain biking. These maps have always been based on data from the OpenStreetMap (OSM) project. In the early days, a map of Europe was just a few hundred megabytes in size and usually fit comfortably on the device’s memory card. However, in recent years, the OSM dataset has grown so extensively that, depending on styling and content, the required storage space for maps can quickly reach into the gigabyte range.

Since my old Garmin device only allows one map to be loaded at a time, switching between, for example, a Germany map and an Alps map isn’t easily possible for me. So, what to do? The answer: build my own custom map, including a style tailored to my personal preferences.

While researching how to build a Garmin-compatible map from OSM data as easily as possible, I came across the Freizeitkarte project by Klaus Tockloth. His website offers a complete development environment for creating maps. Using this framework, I began building my own maps, starting with some initial tests using (very) small data extracts.

My main goal during development was to create a minimalist map consisting of the complete road and path network, selected landmarks that might assist with orientation, shelters or similar places to take cover, and contour lines. A nice side effect: by heavily reducing the map data to just the essentials (mainly the transportation network), the image size of the resulting Garmin map files is significantly smaller.

Here’s a comparison table showing the image size of the generated Garmin map files for the standard Freizeitkarte style versus my minimal custom style:

For all map builds, routing functionality, house numbers, and address search indexing were disabled. I conducted all tests on a dedicated test machine with roughly 0.5 TB RAM, 48 CPUs, and 2 TB NVMe storage. The map generation process was configured to use 100 GB RAM and all available CPU cores. This same machine also builds my global OSM vector tiles (zoom level 14) with a custom style and TileMaker in under 2 hours, as part of various quality assurance processes under the ResultMaps project.

A big thank-you to Klaus for his project, which served as both an inspiration and an extremely useful foundation!

So much data can be added, it’s very cool

I want to try to add a lot of QLD Translink services.

Bonjour à tous,

Avec des utilisateurs marocains nous avons constaté que la frontières entre le Maroc et le Sarah Occidentale était encore présente.

Je ne la vois pas sur la carte ci-dessous.

Mais elle présente sur la version en ligne intégré dans notre logiciel.

目前编辑范围：甘肃省白银市白银区、兰州市；浙江省杭州市、嘉兴市

2025年05月22日

编辑范围：白银市白银区、兰州市 添加道路名称、添加道路信息，添加文化遗址、自然要素内容和一些建筑物。未来有时间可能会修改村庄范围、建筑物边界等。

Hello fellow mappers.

My name is Ayame Otsuki, and I am honored to be nominated as a 2025 voting member of the Humanitarian OpenStreetMap Team (HOT).

I’m based in Japan, and I’ve been engaging in mapping activities as a member of NPO Crisis Mappers Japan since 2015, and I set up a youth team within this community.This February, I gave a presentation about “20years Journey of OpenStreetMap” at State of the Map Japan. Sorry for it’s Japanese

I currently work as a data scientist and analyst at a Japanese telecom company.

What does HOT mean to me?

To me, HOT is a community of people who believe in the power of open data and try to provide humanitarian support across borders. HOT is the one that taught me that a single computer can help some people all over the world.

How did I become involved in HOT?

I first became involved with HOT when I participated in a crisis mapping activity for the 2015 Nepal earthquake, which was organized by Professor Taichi Furuhashi at university. I got to engage in mapping activities since then, and developed an efficient tool (BCr.map) for drawing buildings (rectangles) as my university graduation research project in 2019.

Why do I want to be a voting member?

I would like to be more actively involved in HOT community by becoming a voting member. And also, I want to serve a statistical and objective perspective in HOT’s strategy and governance as a data analysis expert.

My involvement in HOT, mapping, and/or humanitarian response:

I’ve been engaging in mapping activities by using HOT’s tool for 10 years and expand the Crisis Mappers Japan community. I’m also a drone pilot of a Japanese disaster drone rescue team and taught how to operate a drone to local kids.

My most important responsibility as a voting member:

To collaborate with other voting members to maintain HOT as a diverse and sustainable organization. And to support decision-making that strengthens the relationships between local communities and global humanitarian organizations.

How I plan to get involved:

I would love to participate in Community and Training working groups. I’m especially interested in community engagement. Mapping can sometimes be a lonely job, so I want to support mappers and learn how to increase their engagement.

HOT’s greatest challenge and my contribution:

I think one of the greatest challenges HOT faces is ensuring equity in data volume and long-term sustainability as a global movement. I will contribute to sustaining a global, volunteer-based movement, especially in Asian region.

Thank you for this opportunity, and I look forward to connecting with you!

Warm regards, Ayame Otsuki

Twitter/X: https://x.com/ayame_o_13

LinkedIn: https://www.linkedin.com/in/ayameo

حقل

رستوران باران پذیرای شما عزیزان میباشد

So today I get to talk other mappers. and I get to know how they map the challenges the have like; 1. Unavailability of internet connection 2. lack of Devices or tools for mapping etc. After the challenges we get to talk about solutions where we find a solution about getting a router and recharging it so the mappers in a particular area can come together and use it for mapping. And we still Provide systems for those without system to use for mapping till they get their own. I really learned alot from their experiences then by the end of this week i will be able to use JOSM cause we are suppose to be taught by a more experienced mapper. I really enjoy mapping and i still plan to meet mappers around the world so we can share our ideas together

Le portail cartographique Vélodatamap est publié par l’organisme Réseau vélo et marche dans le cadre de son observatoire du réseau national des véloroutes : https://velodatamap.velo-territoires.org/

Nisreen Mahmoud, 2025 HOT Voting Member Nominee

Hello fellow mappers, My name is Nisreen Mahmoud, and I am a GIS and remote sensing expert. I am originally from Sudan, and I currently reside in Egypt. I currently serve as the Supervisor of Surveying, GIS, and Remote Sensing Group in the Khartoum Reconstruction Initiative (KRI). In addition to my supervisory role, I also lead OSM Sudan. Previously, I served as the East African zone coordinator for African Women in GIS (AWiGIS) in 2023. Today, I’m also a proud mentee in the Women+ in Geospatial Mentorship Programme, where I continue growing my leadership and technical outreach abilities. I am passionate about creating spaces where emerging mappers, especially women, African mappers, and those from conflict-affected areas, are able to feel seen, heard, and empowered to lead. I am honored to have been nominated as a 2025 Voting Member of the Humanitarian OpenStreetMap Team (HOT). As someone whose life and work are deeply rooted in both humanitarian response and geospatial science, this opportunity feels especially meaningful. I am pleased to introduce myself and articulate my aspirations to contribute to HOT’s mission.

What Does HOT Mean to Me? HOT represents the fusion of community, technology, and humanitarian action. It’s a space where open data becomes a lifeline—used to empower communities, support climate resilience, and respond to crises. For me, HOT is about building bridges between people and tools, between local knowledge and global support.

How I Got Involved in HOT and Mapping Last year I met Pete Masters in WUF12 in Cairo, Egypt and this was the first time to know about HOT ! I was introduced to the Humanitarian OpenStreetMap Team (HOT) through my professional and volunteer activities in Sudan, and officially joined the HOT team as a Data Analyst Volunteer in December 2024 to lead a team of six volunteer Sudanese cartographers in Khartoum, El Fasher and Port Sudan projects using HOT’s Tasking Manager mapping platform.

Why I Want to Be a Voting Member I want to serve as a voting member to ensure that voices from conflict-affected and underserved regions—especially in Africa—are reflected in HOT’s strategy and governance. I believe strongly in data equity and localization, and I want to support HOT’s transition toward more inclusive and community-driven decision-making.

My Most Important Responsibility as a Voting Member To represent, amplify, and advocate. As a voting member, I see my role as a conduit between the local and the global—helping shape HOT’s priorities while remaining rooted in the realities of the communities we serve.

How I Plan to Contribute I would love to participate in the following working groups: • Community Engagement • Diversity, Equity & Inclusion • Environmental Mapping & Resilience I also hope to support HOT’s outreach in conflict-affected regions, contribute to capacity-building through open training resources, and help strengthen partnerships with local academic and humanitarian institutions.

HOT’s Greatest Challenge – and How I Hope to Help One of HOT’s greatest challenges is long-term engagement and support for local mapping communities—especially in regions affected by displacement, conflict, or lack of infrastructure. I hope to help by advocating for more sustained funding, mentorship programs, and accessible learning pathways that allow communities to move from data consumers to data producers—and leaders.

Mapping has not only shaped my career, it has shaped my purpose: combining spatial science, humanitarian principles, and the power of collective action. I am excited to continue contributing to HOT’s vibrant community as a voting member, helping move forward a more inclusive, equitable, and impactful future for humanitarian mapping.

Thank you for taking the time to read my introduction. I look forward to connecting with fellow nominees, current members, and the wider HOT community to learn from each other and build a more resilient, equitable open mapping future.

Warm regards, Nisreen Mahmoud GIS & Remote Sensing Expert LinkedIn: www.linkedin.com/in/nisreen-mahmoud-862342111 Email: nisreen.abubaker19@gmail.com

So, I got invited to speak at a certain OSM community’s monthly online talk.

Nice, right?

Well, there’s just one problem: I have absolutely no idea what to talk about.

Sure, I could present one of my recent OSM-related programming projects, or share updates on what I’ve been mapping over the past few weeks. Maybe even talk about my personal hopes and dreams for the OpenStreetMap movement—or write a more reflective essay on the movement’s progress and future.

The deadline is still a ways off, so while I mull over the best topic, I figured I’d start with something simple. Something fresh. Something that literally popped into my head minutes before writing this post.

It all starts with a very basic question:

“Who is the most active mapper in city X?”

Why This Question Matters

If answered properly, this question could open the door to a whole series of follow-ups:

• Are they local, organic contributors—not affiliated with a distant organized mapping group but actual residents who have lived in the city for a long time?
• What does their OSM diary look like?
• What have they been mapping lately?
• Are they part of a local mapping group?
• Have they initiated any projects in the past—or are they running one now?
• Can we collaborate with them? Reach out?

Active mappers are often the “local ambassadors” of OSM. They can be our primary point of contact for a specific area—people who know the region inside out. They might even offer local tips, points of interest, or become a valuable reference for others mapping or traveling to the same area. Sometimes, these mappers even maintain detailed wiki pages for their city—outlining points of interest, transit routes, historical context, recent updates, or even personal anecdotes.

Meet Your Mappers

As a regular editor for WeeklyOSM, I come across all sorts of gems—news, tools, and stories from across the OSM universe. One of the more interesting discoveries recently was a tool called mappers.osm.lol, also known as “Meet Your Mappers!”

Here’s how it works:

• Log in with your OSM credentials
• Select a region
• Click “Meet My Mappers”

And voilà—you get a list of active mappers in the selected area.

Neat, right?

How Does It Work?

Thankfully, the source code is open, so I took a peek under the hood.

Turns out, it uses the full changeset archive from planet.osm.org.

The weekly changeset dump alone is around 7.1 GB at the time of this article’s writing.

From what I can tell, the app parses and processes changeset data to build an index of contributors. It uses PostgreSQL for the database and Docker to containerize the app. Configuration is handled via a .env file.

By looking at the programming language breakdown on its GitHub repository, my rough guess is that the app is built primarily with Python (~40%) and JavaScript (~31%). Python handles the backend logic for communicating with the PostgreSQL database and also uses FastAPI—a Python web framework for building APIs.

Changeset data is loaded into a PostgreSQL database, where it can be queried and analyzed. But there’s a catch: it doesn’t process all changesets. By default, it uses a RETENTION_DAYS setting (365 days) to limit the data to just the last year. So if a prolific mapper was active two years ago but hasn’t edited anything since, they won’t show up in the results. That explained why some results didn’t align with my expectations.

What If You Want All Changesets?

If you want to go deeper—say, analyze all changesets from the very beginning—you can do that too. But it comes with a price: disk space and processing time.

The compressed changeset archive is around 7.1 GB, but once extracted, it becomes a very large XML file.

There’s a tool for that: ToeBee/ChangesetMD. It parses changesets into PostgreSQL for querying. It even includes sample queries.

One query, for example, counts all changesets within a bounding box:

SELECT count(id)
FROM osm_changeset c,
     (SELECT ST_SetSRID(ST_MakeEnvelope(-74.0474545, 40.6884971, -74.0433990, 40.6911817), 4326) AS geom) s
WHERE ST_CoveredBy(c.geom, s.geom);

Note:

• ST_MakeEnvelope(…) creates a rectangle (bounding box) defined by two corner points— the lower-left and upper-right corners.
• ST_SetSRID(…, 4326) assigns the spatial reference system (WGS 84).

Want to find the most active user in that area? Just modify it slightly:

SELECT c.user_name, COUNT(*) AS changeset_count
FROM osm_changeset c,
     (SELECT ST_SetSRID(ST_MakeEnvelope(-74.0474545, 40.6884971, -74.0433990, 40.6911817), 4326) AS geom) s
WHERE ST_CoveredBy(c.geom, s.geom)
GROUP BY c.user_name
ORDER BY changeset_count DESC;

This would give you a ranked list of mappers based on the number of changesets they’ve made within the specified area.

But again—processing all of this data yourself requires at least 100 GB of free disk space and a few hours of CPU time. The author of ChangesetMD stated that it takes 2–3 hours to import the dump on a decent home computer. Right now, I’ve only got 38.9 GB of space left. So, yeah… that’s not happening today.

Let’s Stick With the Web App (for Now)

For now, the 1-year retention on mappers.osm.lol is good enough for quick analysis and outreach. It may not uncover the true historic local kings of the map, but it can tell us who’s currently active in the area—and that’s a solid starting point.

By the way, out of curiosity, I looked up who owns the osm.lol domain.

whois osm.lol
dig osm.lol

Registered via porkbun.com, created on 2022-10-29, last updated on 2024-12-12, set to expire on 2025-10-29, and hosted on Cloudflare.

Seems like a small suite of OSM tools lives under that domain. A quick Google Dork (inurl:osm.lol) reveals subdomains like:

• 2008.osm.lol
• way.osm.lol
• first.osm.lol
• files.osm.lol
• i.osm.lol

It seems to be a collection of OSM-related tools created by someone.