[Talk-ht] Propositions for more efficient Nominatims searches and consistent classification of cities, towns, villages and hamlets of Haiti for better rendering on maps

Pierre Beland infosbelas-gps at yahoo.fr
Wed Nov 17 20:36:50 GMT 2010

I have passed a long time searching, correcting town names, try to validate if Health units where located at the right place. This made me realize how many city names where still missing or inconsitently classified for Nominatim searches or Map rendering.

Except for the boundary relations for each levels of the Administrative structure of Haiti, I have not seen propositions about how to classify the different villages, towns and cities of Haiti. And looking at the map of Haïti, I have have seen a lot of inconsistencies. The towns corresponding to Administrative levels Department, Arrondissement and Commune where not seen properly on the map or could not be searched properly in Nominatim.  And some hamlets, peaks or simply names in haiti-tlm-50 corresponding to no housing where classified like important cities.

An other example is Search for Gros Morne. Search was indicating Gros Morne peak but not Arrondissement Gros Morrne.

I started to correct things in Nord-Ouest and Artibonite Departments and modified the various tags to see the effect on Map rendering. The Wiki page http://fr.wikipedia.org/wiki/Haiti presents the Administrative levels of Haiti and estimated population of 2008.

From that, I propose the following guidelines :

Boundary Relations

To facilite Nominatim searches, I propose to modify the Boundary Relations by adding in the name tag a suffix that represents the administrative level (ie. Département, Arrondissement, Commune). If you make a Nominatim search, you will see the effect of this. Try (Arrondissement, Haiti) or (Gros Morne). You will also see thats it facilitate the search for people trying to see administrative level boundaries.

Artibonite Department boundary relation would show :
    <tag k='admin_level' v='4'/>
    <tag k='boundary' v='administrative'/>
    <tag k='name' v='Département Artibonite'/>
    <tag k='pcode:1' v='5'/>
    <tag k='type' v='boundary'/>

Dessalines Arrondissement boundary relation would show :
    <tag k='admin_level' v='5'/>
    <tag k='boundary' v='administrative'/>
    <tag k='name' v='Arrondissement Dessalines'/>
    <tag k='type' v='boundary'/>

Gonaïves Commune boundary relation would show :
    <tag k='admin_level' v='8'/>
    <tag k='boundary' v='administrative'/>
    <tag k='id_commune' v='511'/>
    <tag k='name' v='Gonaïves'/>
    <tag k='pcode:2' v='511'/>
    <tag k='source' v='US Census Bureau, boundary import, 16/01/2010'/>
    <tag k='type' v='boundary'/>

    <tag k='addr:country' v='HT' />
    <tag k='admin_level' v='8' />
    <tag k='alt_name:en' v='Gonaïves' />
    <tag k='is_in:Department' v='Artibonite' />
    <tag k='is_in:country' v='Haiti' />
    <tag k='name' v='Gonaives' />
    <tag k='name:fr' v='Les Gonaïves' />
    <tag k='name:ht' v='Gonayiv' />
    <tag k='population' v='263716'/>
    <tag k='pcode:2' v='511' />
    <tag k='place' v='city' />
    <tag k='source' v='http://fr.wikipedia.org/wiki/Les_Gona%C3%AFves' />

Town nodes
For towns representing the administrative levels 4. Département, 5. Arrondissement and 8. Commune, I propose to add systematically the Population tag indicating population size (The info is provided in http://fr.wikipedia.org/wiki/Haiti for each Administrative level).

The Tags place=city (pop 100,000+) and place=town (10,000 - 100,000) should be reserved to cities corresponding to  Département, Arrondissement and Commune.

The Tag place=village should be reserved for Sections communales (Administrative level=10).
All other places should be classified place=hamlet.

When homonyms exist like Gros Morne, it seems that searches are more efficient in Nominatim when adding the tags addr:country=HT and is_in='The superior Administrative Level'. In this case, all the homonyms will be showed while searching for that name.

Polygons for Residential areas

These polygons when they are to important gives some confusion. I wonder if we should systematiqually avoid using them for hamlets (towns other than Département, Arrondissement, Commune or Section communale).

Pierre Beland
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