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geohacker's Diary

Recent diary entries

A little over a year ago, I wrote about Observe — a new field mapping tool for OpenStreetMap that works offline. There was a lot of interest from the community to use Observe and we got a lot of great feedback. Ever since, we have slowly been working on adding new features and improving the overall performance.

Few weeks ago, we released a new version of Observe. I’m excited to invite you all to test this version and give us feedback. I’ll highlight some of the changes in this release.

You can download the development version of Observe for Android and iOS from here. Note that this uses the OSM Dev API. If you don’t have an account, you can create one. You can read about all Observe features and how to use them in the user manual.

Taking photos and recording traces

Two important features that we wanted to add to improve the field mapping experience of Observe is being able to capture photos and record traces. Photos are critical when it comes to mapping outdoors, as we tend to take pictures of features so we can refer to them later on to create additional tags. For example, I take pictures of the sign boards of businesses so I can enter address and opening hours when I’m back at my computer.

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Location: Balaji Layout, Lingarajapuram, Bengaluru, Bangalore North, Bengaluru Urban, Karnataka, 560005, India

Over the last few months, we’ve been building an offline-first field mapping tool for the OpenStreetMap ecosystem called Observe. Observe makes field surveying and verification easy for mappers, and works on iOS and Android.

Motivation

Field verification is an important part of keeping OSM data accurate. So far, field mapping exercises are largely manual, cumbersome, or require internet connectivity. OpenStreetMap has an active mobile editing ecosystem, but doesn’t offer the same editing experience as iD for beginners. Most often, mapping campaigns need a tool as good as iD that allows edits from the field to verify existing data and improve data quality.

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It’s important to see what exactly happened to features in a changeset. This means identifying the state of each feature, the history, including geometry and tags that changed. The OSM changeset page doesn’t give you a clear idea of what happened in a changeset - you see a list of features that changed, and the bounding box of the changeset.

image

The changeset XML from OpenStreetMap only has current version of the features that changed in the changeset.

Overpass offers augmented diffs between two timestamps that contains current and previous versions of each feature that changed in that period. We put together an infrastructure that queries Overpass minutely, prepares changeset representation as a JSON, and stashes them on S3. The augmented diffs are also cached on S3. This means that the load to Overpass instance can reduce drastically while many of us are looking at the same changeset.

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Location: Indiranagar 1st Stage, Bengaluru, Bangalore North, Bengaluru Urban, Karnataka, 560038, India

I’ll be at State of the Map in Brussels this week presenting all of our work on validating OpenStreetMap data. At Mapbox, we spent the last few months looking at changes that happen in OpenStreetMap closely - geometry, tags, users and the community. I’m really excited to share what we learned, and to open the conversation on how the community can focus on keeping the map from breaking while growing. I’ll be presenting the tools we have been building, insights about problematic changes, response, mechanics of communication and more during my talk.

Our team just published an approach to validating OpenStreetMap data - talking about identifying problematic changes, inspecting them, communicating and eventually fixing. Let me know what you think!

What makes OpenStreetMap special is the community. The community is what makes OpenStreetMap a truly self-healing map. The community is the map.

Map of recently reverted changesets

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Why I'd like to become a HOT member

Posted by geohacker on 27 November 2015 in English.

I’m a software developer at Mapbox based in Bangalore, India, co-leading our data team. Prior to Mapbox, I’ve been part of projects at Karnataka Learning Partnership, Moabi, and organizations like the Center for Internet and Society and Tactical Technology Collective. What makes writing this note special is that I’m in Doha this week, talking about OpenStreetMap data, tools and running a Digital Humanitarian workshop along with Heather Leson and the Qatar Red Crescent Society. In doing so, I’ve been able to engage entrepreneurs, engineers and scientist - introducing them to the largest living map, and OpenStreetMap as a project that is truly “moving the map.” What makes me believe in what we do at HOT and OpenStreetMap is the power of bringing people together.

I have been part of OpenStreetMap since 2008. Since the Haiti activation, I regularly lurked on the HOT mailing list and occasionally mapped. More than mapping, I was drawn to how the OpenStreetMap software infrastructure worked and the idea of mapping anything and everything. I started off my career building data infrastructures and advocated the use of OpenStreetMap software for other use cases. The recent Nepal activation is when I truly got involved in HOT. Right after the earthquake, our team in Bangalore got together to start mapping priority areas. I was communicating with folks at the Kathmandu Living Labs and relaying requests to map, make map data available for download, and working with actors on the ground to design maps for print. I also got a chance to help and learn about imagery acquisition through Mapbox and the Indian Space Research Organisation.

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Location: Unaiza, Doha, Qatar