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Trees (again)

Posted by SomeoneElse on 26 April 2016 in English (English)

A while back I described how I was showing tree types in woodland. The "unfinished business" there was "what about forest areas where the trees have been cleared?". Mapping of that is a bit hit and miss. "Forestry" has been suggested, but doesn't have many takers, and "forest" is actually often used for "the entire forestry area" (at least where I'm interested in rendering tiles for - I suspect it varies considerably worldwide). The wiki page and the standard style rendering discussion don't distinguish, but I thought it was worth trying to separate out "natural=wood" and "landuse=forest" where the latter is used for "the entire forestry area, including where there are currently no trees".

Here's the result:

Trees east of Bolsover

That corresponds to here in OSM's standard style. The dark green bit corresponds to "trees" (natural=wood; if there's a surveyed leaftype then obviously that is shown too). The lighter green bit means "forest, but no trees" (landuse=forest - the lighter green is only visible if there's no natural=wood also there). The forest and wood colours are defined here; here is the leaf_type handling in the stylesheet and here is where the natural and landuse tags are checked to see whether the current object should be treated as "trees with a known leaf type", "trees without a known leaf type" or "forest, but not necessarily trees".

Sidewalks!

Posted by SomeoneElse on 13 March 2016 in English (English)

(or if you're English, "Pavements!")

I finally got this working for tertiary and secondary roads:

Sidewalk rendering example

That location corresponds to here in OSM.

There were three bits to it:

1) Determining which roads should have a sidewalk rendered. This is done in lua, and creates e.g. a road type "tertiary_sidewalk" to go with "tertiary" and "tertiary_link":

https://github.com/SomeoneElseOSM/SomeoneElse-style/blob/sidewalk/style.lua#L230

2) Handle "tertiary_link" the same as "tertiary" in the style's MML, e.g.:

https://github.com/SomeoneElseOSM/openstreetmap-carto-AJT/blob/sidewalk/project.mml#L403

3) Handle "tertiary_link" the same as "tertiary" in the style's roads.mss, e.g.:

https://github.com/SomeoneElseOSM/openstreetmap-carto-AJT/blob/sidewalk/roads.mss#L2363

... except where we want to do something different:

https://github.com/SomeoneElseOSM/openstreetmap-carto-AJT/blob/sidewalk/roads.mss#L1114

"sidewalk_width-z13" etc. are declared at the top:

https://github.com/SomeoneElseOSM/openstreetmap-carto-AJT/blob/sidewalk/roads.mss#L119

There's scope for further tinkering, and I've yet to see how usable it is on a small mobile phone screen in poor light, but it looks OK so far...

Trees!

Posted by SomeoneElse on 14 June 2015 in English (English)

As you may be aware, mapping of areas of trees in OSM is complicated. It's not possible to tell just by looking at the data which of the four(!) approaches described on that page someone is using "natural=wood" and/or "landuse=forest" to mean. It therefore didn't make a lot of sense to me to display them differently on a map created from OSM data.

Last year there was a proposal to record "leaf_type" and "leaf_cycle" separately, which makes sense (though the wider range of non-European tree types doesn't seem to be catered for as well as previously. Unfortunately a previous version of that page suggested that "wood=deciduous" should be replaced by "leaf_type=broadleaved", and a no doubt well-meaning non-local mapper decided to change some areas of mainly deciduous woodland to "leaf_type". Whilst some of these were correct, clearly there are some issues with this, but as I was changing some that I did have local knowledge of, the thing that mainly struck me was that the situation on the ground was far more complicated than previously mapped, or rendered, on OpenStreetMap. I therefore decided to start trying to record "leaf_type" and (when there was enough data, render it. Initial results can be seen here: Trees in Clipstone That location corresponds to here in OSM. There's a lot more to do there, but at least there's a bit more detail than "a large area of trees".

That rendering is created by a combination of this lua script at osm2pgsql data import time and this stylesheet. It's primarily designed for showing England-and-Wales-specific rights of way, but trees seemed like a natural extension.

Notes and Fixmes

Posted by SomeoneElse on 22 December 2014 in English (English)

A while back I wrote https://github.com/SomeoneElseOSM/Notes01 to enable OSM notes to be converted to a useful Garmin format so that you can actually check them when out and about.

A week ago I added support for extracting "fixme" tags from Overpass. There are about 20 notes within 9km of my house, so I was interested to see how many fixmes there were. It turned out that there were 430! As someone said on IRC, "that'll keep you busy over Christmas".

Best Regards,

Andy

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Posted by SomeoneElse on 16 September 2009 in English (English)

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