Maurutania map

[steve owens]

Hi,

Just purchased this app as we are travelling through africa into maurutania. On the home page it lists Maurutania as one of the countries included in the app. When I go to download the country and select africa in the app I dont see it?? Any help Please  cheers

[Horst Müller]

Hello,
I think you have to download the whole map of Africa. Afaik OsmAnd only offers country specific maps when they are offered by the OSM community themselfes.
In other words: OsmAnd does not create sub-regions on its own. They use the maps offered by some OSM-supportes (like geofabrik.de)

Regards,
Horst

Am 23.05.2013 15:50 schrieb "steve owens" <steve...@gmail.com>:

Hi,

Just purchased this app as we are travelling through africa into maurutania. On the home page it lists Maurutania as one of the countries included in the app. When I go to download the country and select africa in the app I dont see it?? Any help Please  cheers

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[steve owens]

Thanks Hoest got it now great app

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[Victor Shcherb]

If someone can provide poly of Mauritania, I think we can provide it as well.

Please make pull request https://github.com/osmandapp/OsmAnd-misc/tree/master/osm-planet/polygons/africa.

Victor

[Harry van der Wolf]

Hi,

I created a simplified poly using QGIS and simply extracted Mauritania. See attached poly file named after it's ISO2 name.
To me this poly seems correct. If so, please let me know. Now that I've got the grip of it, it takes about 5 minutes per country to create a new poly.

Harry

2013/5/23 Victor Shcherb <victor....@gmail.com>

[Harry van der Wolf]

Just to make sure I attached the simplified poly and the original poly. Based on what's available in the github I think you want the original, but the simplified is just as good (I think).

Harry

2013/5/23 Harry van der Wolf <hvd...@gmail.com>

[Victor Shcherb]

I would use simplified it just need to have a little extent in order to render coastline and borders correctly.

If it would be possible, please create pull-request  

https://github.com/osmandapp/OsmAnd-misc/commits/master. It will simplify a lot (just look at 2 last commit)

and this

https://github.com/osmandapp/OsmAnd-tools/commit/0d005a3ef7fb5eb83d8d65fe61c4e469f16bc801

Generated 

http://download.osmand.net/download.php?file=Mauritania_africa_2.obf.zip

http://download.osmand.net/osm-downloads/

Thanks,

Victor

[Harry van der Wolf]

Hi,

I do not exactly understand what you mean.

2013/5/24 Victor Shcherb <victor....@gmail.com>

I would use simplified it just need to have a little extent in order to render coastline and borders correctly.

What do you mean? You don't want the extra space around the border, or do you want extra space around the border?

If it would be possible, please create pull-request  

https://github.com/osmandapp/OsmAnd-misc/commits/master. It will simplify a lot (just look at 2 last commit)

and this

https://github.com/osmandapp/OsmAnd-tools/commit/0d005a3ef7fb5eb83d8d65fe61c4e469f16bc801

I can work with git, but do not understand what you want. Do you mean that I have commit access? Or do you want me to pull a local git repository and simply create a (unified) diff for you?
Please explain.

Harry

 

[Victor Shcherb]

I want extra space around the border (around 50 meters).

No need to work with git, you just need to create /copy file on github this is doable from browser.

You press Fork and edit on file and press create pull-request.

Regards,

Victor

--

[Ab_fab]

For your information :

Jocelyn Jobert admins the pool of servers of OpenStreetMap France, and takes care of the osmose quality tool [1]:

In order to add new countries to be analysed, he developped this tool and interface, quite easy to use (just need the osm relation id for the boundary as input and few parameters to adjust the simplification of the polygon) :

http://osm102.openstreetmap.fr/~jocelyn/polygons/index.py

It's possible to adjust the X setting as follows :

  - X > 0, polygon surrounds the boundary.
  - X = 0, follows the boundary as close as possible, depending on the simplification parameters Y & Z
  - X < 0, polygon is included inside the relation.

Bye

-----------------------------

[1] http://osmose.openstreetmap.fr

2013/5/23 Victor Shcherb <victor....@gmail.com>

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ab_fab
"Il n'y a pas de pas perdus", Nadja

[Harry van der Wolf]

Thank you for mentioning it.

However, I've seen that tool but it requires to have the id, like you mention, and you can only acquire that by clicking on the boundary. This works fine for a city or small (admin) boundary, but not for an entire country as both JOSM and Potlach (inside OSM) do not allow your to download/work with such a huge chunk of data. That's why I switched to QGIS which has a very easy way of working as well (I will write a technical article for the wiki) based on shape maps (or QGIS projects), which are by default much maller.

 

I would appreciate though if you can tell me if there is a way to get the id from a country border from JOSM or Potlach.

 

Harry

2013/5/24 Ab_fab <gamm...@gmail.com>

[Ab_fab]

You can easily get it from http://www.openstreetmap.org

Zoom on a fraction of the boundary, click on the top right corner button (for layers selection) and select "explore map data" (or similar, my interface is in French ^^)

When I try it for Mauritania, I get the list of elements, including this way "Border Western Sahara - Mauritania"

http://www.openstreetmap.org/browse/way/22689304

The detailled description of the way indicates that this way is part of the "Mauritanie" relation, with appropriate link to its description, and obviously its id.

http://www.openstreetmap.org/browse/relation/192763

Hope it clarifies !

2013/5/24 Harry van der Wolf <hvd...@gmail.com>

[Stephan75]

Hello Harry,

you can also go to http://nominatim.openstreetmap.org and enter there the name of any country or region where you assume that it has a boundary relation.

In the result list of the search each result is marked with a little sign. If it is the one with a signpost positioned on a kind of a little area, this is the sign for relation!

Click that result and you will get detailed information about that relation ... even with the ID number of it from the raw OSM data.

Success?

Stephan

[Harry van der Wolf]

Hi Stefan75 and Ab_fab,

 

Thanks for your suggestions.

Both options work where Stefan's way works slightly simpler. In Ab_fab's manner you have to be careful. I thought I had the id, but it turned out to be the ID of Algeria, the nabor country, as they share the same border of course.

 

I need to play with the parameters now to get the 50-60 km buffer around the border Victor needs in the poly.

But it is simpler then the QGIS method.

 

Harry

[Harry van der Wolf]

2013/5/24 Victor Shcherb <victor....@gmail.com>

I want extra space around the border (around 50 meters).

50 meters is undoable. The tools are not that accurate and neither is a person if he needs to handdraw it.
Do you mean 50km? Because that's about the current size.
You can hardly go smaller then 2 km and you will still have over 2500 points.

Harry

[Ab_fab]

Victor mentionned a 50 *meters* buffer, not 50 km

2013/5/24 Harry van der Wolf <hvd...@gmail.com>

Hi Stefan75 and Ab_fab,

 

I need to play with the parameters now to get the 50-60 km buffer around the border Victor needs in the poly.

But it is simpler then the QGIS method.

 

Harry

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[Harry van der Wolf]

Hi, That was a typo. sorry,
But that's what I just responded. I tried it but a 50 meter border is really undoable: The tools are just not that accurate. And by hand it will take hours and hours. I will not do that.

Harry

2013/5/24 Ab_fab <gamm...@gmail.com>

[Victor Shcherb]

Hi,

Could you let us know what is the current status?

- Border should be bigger than original border

- Border should include as less neighbor country as possible (usuall 100m-1km is enough), keeping in mind that area will be rendered twice. Also keeping in mind to many points, worse extracting results.

- Coastline can be included with much bigger buffer. It is common practice to not create islands border but create a big ocean/sea border containing islands.

Victor

 

[Harry van der Wolf]

Hi,

Yesterday evening I did the fork and pull request for the updated Mauritania poly, which you already merged in the master branch. That one has 300-500 meters border, but also for the coastline border. However, the coastline border in the original, not simplified poly is already much wider and includes two small islands.

The poly from last night has been created using the Mauritania ID and the poly tool at http://osm102.openstreetmap.fr/~jocelyn/polygons/index.py
As such the tool is very simple, but it turns out that "tweaking" the buffer around the border takes some trial and error and is different per changing longitude (1 minute on the map is 69 km at the equator, but decreases towards the poles), but is also dependent on the size of the poly, be it a country or a region or a city.

I tried to make the border as narrow as possible but it is a delicate equilibrium between narrowness of the buffer and the number of points in the poly: The narrower the border, the more detail you need, the more points you get.

When looking at the Mauritania poly in JOSM (for example), you can see that the southern border with Senegal is very tortuous. To maintain a narrow border requires a lot of points in the polygon. By far the majority of the polygon points (my guess: 80%) is in that small part of the southern border alone.

So I just did a manual correction of that southern border as the number of points in the poly could really be reduced.
I just did another pull request which contains the optimized poly.
For me it is now finished :)

Harry

2013/5/25 Victor Shcherb <victor....@gmail.com>

[Ab_fab]

Good morning,

For your information, please note that Jocelyn's service to generate simplified polygons surrounding OSM boundaries is now available at the following url :

http://polygons.openstreetmap.fr/

Source : http://lists.openstreetmap.org/pipermail/dev/2013-June/027079.html

2013/5/25 Harry van der Wolf <hvd...@gmail.com>