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.

Observe is a cross-platform, offline-first field mapping tool for OpenStreetMap, perhaps the first of its kind. Our primary goal was to build an application that makes field observation easy, and to provide a comparable experience to iD on Android and iOS — with some success. Observe focuses on browsing OSM data and allows users to add new points or verify existing information. The edits made offline are stored on the phone and uploaded when the mapper goes online. Observe is a product of several iterations of user research and a couple years of conceptualization.

Using Observe

Today, we’re launching development builds for both Android and iOS. You can download the Android APK from here or request for access if you’re on iPhone (you’ll have to submit a request with your email, then download and install a profile that’s sent to your email, we’ll then let you know when you can install the app). The app will be configured to use the OSM development API by default, as opposed to the production API. If you don’t have an account on the development API, create one. We want to let community members test Observe thoroughly and to give us valuable feedback before releasing a version for the production API.

Functionality

Observe allows mappers to add new points, move/delete existing points, and edit attributes of existing ways. Observe does not support complex way drawing operations or relation editing at the moment. To learn more about how to use Observe, read the user manual. Observe creates one changeset per feature. Past experience has led us to make this choice - it’s easy to revert the single defective changeset without losing many good changes. The app also supports a very rudimentary resolution of conflicts by allowing to see the changes upstream, and allowing to continue uploading.

Presets

Observe uses presets from iD. We’ve tried to include as many as possible, but there could still be certain combinations missing since this is an MVP. To keep the MVP performant, a handful of features are not available for editing. These will still be available on the base map.

Offline mapping

You can download areas of interest for editing offline. Observe will allow you to download areas of up to about 400 square kilometers, but it’s still dependent on your device, storage space, and quality of network. Edits made while offline are stored on the phone, and uploaded when the device is back online. The status of each upload can be seen in the contributions screen. When creating an offline pack, Observe downloads OSM data, base map tiles, and satellite imagery tiles for that area. When the user pans the map, while connected to the internet, these areas are automatically refreshed to fetch latest data.

Use-cases for Observe

We think Observe is excellent for the following use-cases:

• Quickly map POI features - Observe is best for adding POIs. As you walk down the street, it only takes a few seconds to add a shop, bus stop, or any point of interest to OpenStreetMap.

• Community mapping parties and field mapper exercises - Observe will work great particularly for mapping parties that identify clearly what feature to map beforehand. For instance, gathering a group of people to map trees in a neighborhood could be a really easy task with Observe.

• Verify names of streets, shops, or other features - A lot of times we want to verify and correct tags of existing features. Observe allows us to edit tags and to add new tags to ways.

Development and future

Observe is built using react-native, and Mapbox GL. There are some really cool ideas on the list, and we’re exciting to see what feedback you have. On the roadmap are:

1. Clear outstanding bugs, technical debt, and validate decisions. These are documented on GitHub.
2. Tasking Manager integration
3. Validation - both preset level and geometry level
4. Notes - add a layer of OSM notes, and potentially add notifications
5. Integrate Nominatim for search

Feedback

We’re looking for feedback. You can open a ticket in http://github.com/developmentseed/observe and let us know any bugs or issues you come across while using Observe. We’ve only tested Observe on a handful of devices, so if it doesn’t work on your phone, let us know. Any reasonably performing phone with Android 8+ should work well, as well as iOS 10.