How to use a text field in a view to link to maps (OpenStreetMap + OpenTopoMap)

In the view, make a Global: Custom text field. This field should be located behind (down) other fields you want to use the fields content of.

Look carefully to the replacement patterns; they tell you what machine fields are available as parameters.

Here is an example of the view PLACES:

{{ edit_node }} == Link to edit Content
{{ title }} ==
{{ field_pl_name }} ==
{{ field_pl_type }} ==
{{ field_pl_address }} ==
{{ field_pl_parent_place }} ==
{{ field_pl_coordinates }} ==
{{ nothing }} == Custom text

We are using the geofield approach with coordinates Latitude, Longitude as a couple in the machine field. The field contains HTML code which needs to be stripped by the "clean" function first before the coordinates can be used separately.

Map providers used

The platform uses two external map viewers:

Provider	Used For	Reason
OpenTopoMap	Continent, Country, Region, Province, City, Village, Square, Street	Clean, readable, calm map style; ideal for borders and terrain; no marker needed
OpenStreetMap.org	Point	Supports marker display via URL parameters

This hybrid approach keeps the system simple and readable while still allowing precise point-level markers.

URL formats

OpenStreetMap (with marker support)

In the example of going with this field to look to the map at OpenStreetMap, you should first study what OpenStreetMap requests as an URL in order to show a map centered around a point given by coordinates, and this with a certain zoom level.

Basic centered map:

https://www.openstreetmap.org/#map=<zoom>/<latitude>/<longitude>

If you also want to display a marker at the coordinates spot then it becomes:

https://www.openstreetmap.org/?mlat=<latitude>&mlon=<longitude>#map=<zoom>/<latitude>/<longitude>

This form is used only for the Point type, where a marker is essential.

OpenTopoMap (no marker support)

OpenTopoMap uses a slightly different URL format:

https://opentopomap.org/#map=<zoom>/<latitude>/<longitude>

Example:

https://opentopomap.org/#map=6/50.85/4.35

Notes:

OpenTopoMap does not support markers.
It may rewrite the URL after loading (rounding coordinates). This is normal behavior.

Final Twig code (hybrid solution)

If we on top of this want to use the TYPE field (Continent, Country, City,...) to set the zoom level, and use OpenTopoMap for all types except Point (where we still want a marker via OpenStreetMap), the final code is like this:

{% set clean = field_pl_coordinates|striptags|trim %}
{% if clean %}
  {% set parts = clean|split(',') %}
  {% set lat = parts[0]|trim %}
  {% set lon = parts[1]|trim %}

  {% if field_pl_type matches '/Continent/' %}
    {% set zoom = 3 %}
  {% elseif field_pl_type matches '/Country/' %}
    {% set zoom = 5 %}
  {% elseif field_pl_type matches '/Region/' %}
    {% set zoom = 7 %}
  {% elseif field_pl_type matches '/Province/' %}
    {% set zoom = 7 %}
  {% elseif field_pl_type matches '/City/' %}
    {% set zoom = 10 %}
  {% elseif field_pl_type matches '/Village/' %}
    {% set zoom = 10 %}
  {% elseif field_pl_type matches '/Square/' %}
    {% set zoom = 16 %}
  {% elseif field_pl_type matches '/Street/' %}
    {% set zoom = 18 %}
  {% elseif field_pl_type matches '/Point/' %}
    {% set zoom = 18 %}
  {% else %}
    {% set zoom = 10 %} {# default #}
  {% endif %}

  {# Use OpenStreetMap only for Point (marker needed) #}
  {% if field_pl_type matches '/Point/' %}
    <a href="https://www.openstreetmap.org/?mlat={{ lat }}&mlon={{ lon }}#map={{ zoom }}/{{ lat }}/{{ lon }}" target="_blank">🌐</a>
  {% else %}
    <a href="https://opentopomap.org/#map={{ zoom }}/{{ lat }}/{{ lon }}" target="_blank">🌐</a>
  {% endif %}
{% endif %}

Zoom levels to be used

OpenStreetMap and OpenTopoMap use fixed zoom levels to define how much detail a map shows, from global views to building-level precision.

Zoom	Visible Area	Meters per pixel (approx.)	Typical Use
0	Whole Earth	156412	Global overview
1	Continents	78206	Very broad context
2	Large regions	39103	Continental regions
3	Countries	19551	National maps
4	Large provinces	9776	Regional overview
5	Regions / states	4888	Macro-regional planning
6	Large metropolitan areas	2444	Wide urban areas
7	Cities	1222	City-level context
8	Large towns	610	Town overview
9	Towns	305	Local town context
10	Urban areas	152	City districts
11	Neighborhoods	76	Neighborhood-level detail
12	Local areas	38	Local context
13	Streets	19	Street-level detail
14	Street blocks	9.5	Street blocks, POIs
15	Buildings	4.8	Building footprints
16	Building details	2.4	Entrances, precise locations
17	Entrances	1.2	Very fine detail
18	Very fine detail	0.6	Door-level precision
19	Ultra-detailed	0.3	High-precision mapping (if available)

These are suggestions of course, and personal adjustment is your choice.