Map corrections

Larry Babcock shared this question 11 months ago

I find instances where a trail shown on my Lomap is wrong or not there at all. What is the procedure for submitting corrections?

Comments (4)


LoMaps are derived from OpenStreetMap (OSM).

OSM is the "Wikipedia of Maps"; it is created by volunteer map contributors/editors (the general public).

The easiest way to indicate an error in OSM is to add a Note. Your note will appear as a red icon on the map (but only if you enable the option to display Notes). OSM's volunteer map-editors will see your Note and, depending on their interest and availability, someone may act on your Note.

You can create Notes on OSM's web-site or, more conveniently, directly from Locus Map.

You don't need an OSM account to create a Note. However, without an account, your Note will be authored by "Anonymous" and map-editors won't be able to contact you if they have questions.

Alternately, you can make the changes yourself. Get a free OSM account, read/view the tutorial information, and draw the missing trail yourself using one or more GPS tracks you've recorded (if you have any or just use other people's tracks). This is what I did.

I've been updating the High Peaks region of the Adirondack Park since May 2016. I hike in the area very frequently so I have lots of recorded data that I've entered into OSM (over 300 edits so far). I started with simple things first (adding missing campsites) and slowly progressed to more complex tasks. The map now shows 99% of all trails including details like routes, trail-difficulty, lean-tos, campsites, bridges, toilets, viewpoints, guideposts, ladders, staircases, etc. It's an enjoyable hobby and my contributions help others discover this beautiful place.!44.1393!-73.868


Now I am intrigued.  I have a friend who is doing red-lining which, in New Hampshire parlance, is walking every trail.  He will gladly give me a .kmz of his hikes from his Garmin.  So how do I go about finding who the other contributors for New Hampshire are so that we are not wasting a lot of effort on the same trails?

From: Locus Map

Sent: Sunday, October 29, 2017 3:30 PM

To: Larry Babcock

Subject: New Comment in "Map corrections"


Red-liners are an excellent source of data as are hikers seeking to complete the NH48 Grid (FWIW, I'm 3/4 of the way through the ADK Grid).

I congratulate you for your forward thinking. Getting in touch with the local map-editors is a very good strategy. If an area is being managed by one or more frequent contributors/editors, the most courteous thing to do is contact them first.

To determine who created a specific "way" (OSM parlance for road, trail, river, stream, etc) or other mapping object is to query it. In the map's right-hand menu you'll find a question-mark icon. Click it then click on a map object. A left-hand menu will appear with search results. Click the most appropriate one (typically the first one in the list) and its properties, or "tags", will be displayed.

For example, here's the Wamsutta Trail and it was created by "iamkryzs" (who also happens to be a map-editor who I have communicated with in the past).

Another technique is to use this web-site which displays a historical list of all changes for a given map area. I've centered it on the northern Presidentials:

You can see that someone named "j3kestrel" made several changes ... but many people have been involved in this area. It's best to contact whoever has done a lot of editing in the area because they will (probably) know it best.

If you see an author mention "MapRoulette" then they may not necessarily be a regular contributor to that area or "know it best". MapRoulette is like a giant task list. Anyone can pick a task and go off somewhere on the map to complete it. Usually the tasks are common mapping bugs and MapRoulette is a game-like approach to get people to fix these bugs wherever they may be.

It is best to use more than one GPS track as a reference for drawing a trail. The more tracks, the better. A single GPS track is better than nothing but it can be many meters off the true path. With multiple tracks, you can manually "average" them to help reduce errors.

Another source of GPS tracks is OSM itself! The general pubic can upload GPS tracks to a common, public folder. When a map-editor wishes to create/modify a trail, they can display the relevant tracks from that public folder. You don't even have to be a map-editor to see those tracks. In OSM's right-hand menu, click the "Layers" icon then enable "Public GPS Traces".

Wikiloc is another source of GPS traces. Strava's Running Heat Map is also very good because it shows many overlapping GPS tracks in "heat map" format. However, to my knowledge, you can only display Strava's Heat Map in the JOSM editor.

There are three mapping editors available: ID, Potlatch, and JOSM. ID runs in a browser and is the easiest, most user-friendly means to add/modify OSM's mapping data. I've never used Potlatch so I can't comment on it. JOSM is the most sophisticated and powerful but has a bit of a steep learning curve. I started with ID and switched to JOSM because it provides me with better control plus it can validate your work and identify mistakes.

There's a Beginner's Guide available on However, this video by Blake Girardot provides a quick (and practical) introduction to map-editing with the iD editor. He volunteers his time for "HOT" (Humanitarian OpenStreetMap Team) which involves mapping areas of the earth devastated by natural disasters.



thank you Taras for detailed descriptions. Larr,y please follow the instructions from Taras he mentioned all important points.

Thank you guys.