In MapComplete, it is relatively simple to make your own theme. This guide will give some information on how you can do this.
Before you start, you should have the following qualifications:
- You are a longtime contributor and do know the OpenStreetMap tagging scheme very well.
- You are not afraid of editing a .JSON-file
- You're theme will add well-understood tags (aka: the tags have a wiki page, are not controversial and are objective)
- You are in contact with your local OpenStreetMap community and do know some other members to discuss tagging and to help testing
If you do not have those qualifications, reach out to the MapComplete community channel on Telegram or Matrix.
The custom theme generator is a special page of MapComplete, where one can create their own theme. It makes it easier to get started.
However, the custom theme generator is extremely buggy and built before some updates. This means that some features are not available through the custom theme generator. The custom theme generator is good to get the basics of the theme set up, but you will have to edit the raw JSON-file anyway afterwards.
A quick tutorial for the custom theme generator can be found here.
If you have your .json file, there are three ways to distribute your theme:
- Take the entire JSON-file and base64 encode it. Then open up the
url
https://mapcomplete.osm.be?userlayout=true#<base64-encoded-json-here>
. Yes, this URL will be huge; and updates are difficult to distribute as you have to send a new URL to everyone. This is however excellent to have a 'quick and dirty' test version up and running as these links can be generated from the customThemeGenerator and can be quickly shared with a few other contributors. - Host the JSON file on a publicly accessible webserver (e.g. github) and open
up
https://mapcomplete.osm.be?userlayout=<url-to-the-raw.json>
- Ask to have your theme included into the official MapComplete - requirements below
Did you make an awesome theme that you want to share with the OpenStreetMap community? Have it included in the main application, which makes it more discoverable.
Your theme has to be:
- Make sure the theme has an English version. This makes it easier for me to understand what is going on. The more other languages, the better of course!
- Make sure your theme has good tagging
- Make sure there are somewhat decent icons. Note that there is no styleguide at the moment though.
The preferred way to add your theme is via a Pull Request. A Pull Request is less work for the maintainer (which makes it really easy and for me to add it) and your name will be included in the git history (so you'll be listed as contributor). If that is not possible, send the .Json-file and assets, e.g. as a zip in an issue, per email, ...
Via a pull request:
- Fork this repository
- Go to
assets/themes
and create a new directoryyourtheme
- Create a new file
yourtheme.json
, paste the theme configuration in there. You can find your theme configuration in the customThemeBuilder (the tab with the Floppy disk icon) - Copy all the images into this new directory. No external sources are allowed! External image sources leak privacy
or can break.
- Make sure the license is suitable, preferable a Creative Commons license or CC0-license.
- If an SVG version is available, use the SVG version
- Make sure all the links in
yourtheme.json
are updated. You can use./assets/themes/yourtheme/yourimage.svg
instead of the HTML link - Create a file
license_info.json
in the theme directory, which contains metadata on every artwork source
- Add your theme to the code base: add it into "assets/themes" and make sure all the images are there too. Running ' ts-node scripts/fixTheme ' will help downloading the images and attempts to get the licenses if on wikimedia.
- Add some finishing touches, such as a social image. See this blog post for some hints
- Test your theme: run the project as described in development_deployment
- Happy with your theme? Time to open a Pull Request!
- Thanks a lot for improving MapComplete!
There are three important levels in the .JSON-file:
- The toplevel describes the metadata of the entire theme. It contains the
title
,description
,icon
... of the theme. The most important object islayers
, which is a list of objects describing layers. - A
layer
describes a layer. It contains thename
,icon
,tags of objects to download from overpass
, and especially theicon
and a way to ask dynamically render tags and ask questions. A lot of those fields (icon
,title
, ...) are actually aTagRendering
- A
TagRendering
is an object describing a relationship between what should be shown on screen and the OSM-tagging. It works in two ways: if the correct tag is known, the appropriate text will be shown. If the tag is missing (and a question is defined), the question will be shown.
Every field is documented in the source code itself - you can find them here:
- The top level
LayoutConfig
- A layer object
LayerConfig
- The
TagRendering
- At last, the exact semantics of tags is documented here
A JSON-schema file is available in Docs/Schemas - use LayoutConfig.schema.json to validate a theme file.
There are few tags available that are calculated for convenience - e.g. the country an object is located at. An overview of all these metatags is available here
A tagRendering can have a group
-attribute, which acts as a tag. All tagRenderings with the same group name will be
rendered together, in the same order as they were defined.
For example, if the defined tagrenderings have groups A A B A A B B B
, the group order is A B
and first all
tagrenderings from group A will be rendered (thus numbers 0, 1, 3 and 4) followed by the question box for this group.
Then, all the tagRenderings for group B will be shown, thus number 2, 5, 6 and 7, again followed by their questionbox.
Additionally, every tagrendering will receive a the groupname as class in the HTML, which can be used to hook up custom CSS.
If no group tag is given, the group is `` (empty string)
By default, the questions are shown just beneath their group.
To override this behaviour, one can add a tagrendering with id questions
to move the questions up.
To add a title to the questions, one can add a render
and a condition.
To change the behaviour of the questionbox to show all questions at once, one can use a helperArgs in the freeform
field with option showAllQuestions
.
For example, to show the questions on top, use:
"tagRenderings": [
{ "id": "questions" }
{ ... some tagrendering ... }
{ ... more tagrendering ...}
]
To show all the questions of a group at once in the middle of the tagrenderings, with a header, use:
"tagRenderings": [
{
"id": "questions" ,
"group": "groupname",
"render": {
"en": "<h3>Technical questions</h3>The following questions are very technical!<br />{questions}
},
"freeform": {
"key": "questions",
"helperArgs": {
"showAllQuestions": true
}
}
}
{ ... some tagrendering ... }
{ ... more tagrendering ...}
]
All the texts are actually HTML-snippets, so you can use <b>
to add bold, or <img src=...>
to add images to
mappings or tagrenderings.
Some remarks:
- links are disabled when answering a question (e.g. a link in a mapping) as it should trigger the answer - not trigger to open the link.
- If you include images, e.g. to clarify a type, make sure these are icons or diagrams - not actual pictures! If users see a picture, they think it is a picture of that actual object, not a type to clarify the type. An icon is however perceived as something more abstract.
Not publishing because 'it is not good enough'. Share your theme, even if it is still not great, let the community help it improve
Making a tagrendering as if it were a question only. If you have a question such as: Does this bench have a backrest?,
it is very tempting to have as options yes for backrest=yes
and no for backrest=no
. However, when this data is
known, it will simply show a lone yes or no which is very unclear.
The correct way to handle this is to use This bench does have a backrest and This bench does not have a backrest as answers.
One has to think first in terms of what is shown to the user if it is known, only then in terms of what is the question I want to ask
MapComplete is in the first place a tool to help non-technical people visualize their interest and contribute to it. In order to maximize contribution:
- Use simple language. Avoid difficult words and explain jargon
- Put the simple questions first and the difficult ones on the back. The contributor can then stop at a difficult point and go to the next POI
- Use symbols and images, also in the mappings on questions
- Make sure the icons (on the map and in the questions) are big enough, clear enough and contrast enough with the background map
One layer should portray one kind of physical object, e.g. "benches" or "restaurants". It should contain all of them, disregarding other properties.
One should not make one layer for benches with a backrest and one layer for benches without. This is confusing for users and poses problems: what if the backrest status is unknown? What if it is some weird value? Also, it isn't possible to ' move' an attribute to another layer.
Instead, make one layer for one kind of object and change the icon based on attributes.
Using layers as filters - this doesn't work!
Use the filter
-functionality instead
There are a few advanced features to do fancy stuff available, which are documented only in the spec above - for example, reusing background images and substituting the colours or HTML-rendering. If you need advanced stuff, read it through!