More illustrations and animations would improve this page significantly

Introduction to JOSM

JOSM Terminology

Node

A node is a point.

Way

A way is a line connecting multiple nodes. Way, therefore, is a general term for series of joined nodes, not just for roads or ways in reality.

Relation

A relation is an ordered sequence of ways and nodes, a logical container used to group elements.

Area

An area is a way whose ends are connected.

Tag

Tags describe what each node or way represents. Tags are organized into "keys" and "values." Keys are basically larger categories, such as "Highway" or "Land Use," while values are specific features, such as "Primary Road" or "Residential Street," and "Residential" or "Retail" land use.

Have a look at Objects - The basic building blocks of OSM data and maps for more information.

If a road or track or path is curved, the curve is approximated using a number of nodes within a way, and short lines connecting them. If a way has a direction, that is indicated partly by using tags. For example, "oneway=yes" is a road that goes only in one direction. (See Conventions in "Creating certain types of ways" at the bottom of this page for special considerations when creating a one-way road.) Other tags refer to being on the left and right of the direction of way along the way.

Start a JOSM

JOSM is a Java program, can be run from main page.

Your first edit with JOSM

Welcome screen

When JOSM starts, it presents you with a few messages about recent changes in JOSM. You should have a look at this page from time to time as it keeps you informed on some of the more interesting changes.

Downloading

The next step is to download some data. You can practice using JOSM by downloading your neighbourhood or locality you know or just recently visited.

OSM data

Next, add data for that area from main server. Open the download dialog by clicking Download from OSM (Ctrl+Shift+↓).

"Slippy Map" tab will be displayed, a map of the world. But you need to select smaller area for your edit, not entire globe (thus you will see "Download are too large" message).

To move around the map and select the specific area you want to download, there are several tools:

• Click with the right mouse button to drag the map
• Use the scroll wheel to zoom in and out
• click with the left mouse button to define an area.

After "Download are too large" error disappeared and you selected a region, click "Download" to fetch the data from main server.

Enable Aerial imagery

For most places on earth, there at least one imagery available. You can pick one from Imagery menu at the top of the editor.

Editing in JOSM

JOSM is an offline editor which means everything you do won't be visible for anyone else until uploading it to the server. This makes it possible to experiment and repeatedly moving, tagging, adding and deleting elements without breaking anything. Subsequent actions on a single element will go into the database as a single modification when uploaded.

Adding a Node or a Way

The first step of actual editing is to add a node or way to the OSM data. You can add standalone nodes or you can add nodes to ways, especially where there is a junction between two ways or a significant change in direction of the way.

To add a node, highlight the "Node" button, either by clicking the 2nd button in the left menu bar , or by hitting the "A" key on the keyboard (the 2nd button should then be highlighted). Then, move the mouse cursor over where you want the node, over a way or over your GPS track (if you uploaded one) and left click wherever you want a node. A white dot (a selected node) should appear and a rubber-line span from that dot to the mouse cursor. If you create subsequent nodes, the earlier nodes will be shown as yellow dots.

A series of joined nodes forms a way.

Adding Tags

Ways or nodes on their own are not of much use unless they are tagged to say what they represent. The Map Features web page ​Map Features shows and explains the most used tags that could be used on a point or way.

The first step in adding tags is to be sure the Tags/Membership Dialog is open on the right hand side of JOSM. The button on the left should be highlighted. If it is not highlighted, click on it or hit Alt+Shift+P. You will see the Tags/Membership Dialog, which has three buttons: Add, Edit and Delete.

To edit the properties of a node or way (such as adding a tag) in the Tags/Membership Dialog, the way or node must be selected.

1. Enter Select mode by clicking on of the left-hand icons or hitting the S key.
2. Highlight the way or point you wish to select. Click the Add button.
3. A dialog box will appear, and you will be asked to select a key and a value for each tag. Type in the key/value pair that represents the tag you are creating. For example, for the key, you might type "highway," and for the value "secondary" (no quotes).
4. Click OK. You have now tagged your way. You can add several tags to one object.

Instead of adding tags manually you can also use Presets.

Uploading to OSM

If you are happy with all that you have done then you must upload your work to the OSM server. Click on the green up arrow .

JOSM will give you an overview of the elements that it is about to upload. You will be asked to provide a short text summary and the source of your edits. This description will be saved with your data on the server and provides information, for example, for the ​Recent Changes list.

Click on "Upload changes" and your data will be uploaded, saved and visible to everyone else.

See Upload to OSM for further information on uploading.

What next

Results of your job

• Will appear at ​openstreetmap.org "Standard" layer within few minutes
• Data in your routing software, maps and other services: will be updated per each service (from minutes to days, weeks and months)

Tell your friends

• How it is easy to update data, how your results get displayed quickly. Truck drivers, couriers, photographers, bikers, journalists, fisherman and simply runners with GPS are always welcome in OSM.
• Precise and actual information may affect how you make decisions in your life. The more people active in project - the faster data gets updated. And while ​a few contributors can be called as "active" at given point in time. Every small change advances OSM to complete and actual state
• OSM data may be viewed as clocks: without an arrow you wouldn't know minutes. it's often gets outdated - simply refresh it, when clock "stops" we wind up.
• OpenStreetMap is about whole planet in the same way how your clock about current time

If you use JOSM as main editor

(stub) Consider fine-grained customization based on your needs and your tasks.

Conventions in Creating Certain Types of Ways

A couple of other points about creating ways.

1. Dual-carriage ways (divided roads such as motorways, interstate highways, etc.) should be drawn as two separate parallel ways, with each carriage way being a different direction.
2. If a street is one-way (including the individual carriage ways of a dual-carriage way), that way should be drawn in the direction of travel.
3. Key-and-value tagging is case sensitive. All keys should be entered in lower case.

External links

• ​Mapping with JOSM with animations, by Mapbox team, covers mostly the same topics
• ​Your first steps with JOSM - the Java OpenStreetMap editor 09/02/2016 by Ramya Ragupathy at Mapbox blog

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