Import SEN ARD-STL CSE Saint-Louis

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06/30/13 : Import is done

Goals

This is the first import for Senegal done as a part of the HOT Senegal Project. Its goal is to include the ARD-STL (Agence Régionale de Développement de Saint-Louis) & CSE (Centre de Suivi Ecologique) data for administrative boundaries and administrative centers for the region of Saint-Louis, Senegal into OSM.

Schedule

  1. Preparation, discussion - Second half of May 2013
  2. Import - expected in ending may 2013

Import Data

Data description

The dataset consists of 3 shapefiles covering Saint-Louis region :

- one shapefile "Limite_Communauté_Rurale" : 18 polygones for the 18 rural communities of Saint-Louis region with following attributes : NOM, Superficie, Pop_04, Périmètre, Nb_Part.
Only the attribute NOM is tagged in OSM, considering the authorization given by ARD Saint-Louis.

- one shapefile "Chef-Lieu_de_CR" : 19 points for the 18 administrative centers of the 18 rural communities of the Saint-Louis region (19th point concerning Rao village is a mistake, this point will be ignored) with following attributes : TOPONYMIE, POP, ADMI1, ADMI2, 1DMI3, ADMI4, ADMI5, ECOLP, PSANTE, EAU, COMMERC, ROUTE, INDEX, POP_1, X_COORD, Y_COORD, NOMCR, NOMARRO, NOMDEPA, NOMREGION, INDEX05, ECOLEP, ECOL05, Dist_SL.
Only the attribute TOPONYMIE is tagged in OSM, considering the authorization given by ARD Saint-Louis.

- one shapefile "communes" : 20 points for the 20 communes of the Saint-Louis region with following attributes : Id, NomCommune, Superficie, Nb_Part.
Only the attribute NomCommune is tagged in OSM, considering the authorization given by ARD Saint-Louis.

Background

ODbL Compliance verified: YES
The authorization given by ARD Saint-Louis was approved by the OSMF License Working Group as ODbL compatible. The original authorization given by ARD Saint-Louis is held by Augustin Doury and a copy is avaible here

Import Type

This is a one-time import done manually in JOSM.

Data Preparation

Data Reduction & Simplification

The data will be reduced only to the keys listed above (NOM for "Limite_Communauté_Rurale", TOPONYMIE for "Chef-Lieu de CR", NomCommune for "communes").

Tagging Plans

These tagging plans treat with administrative data and must be related to the tag boundary=administrative and especially to the row concerning Senegal in the table of admin_level=*. A chapter in WikiProject Senegal is related to this subject : Frontières administratives.

We deal with one of the lowest administrative level of Saint-Louis region, and more generally of Senegal, this is the admin_level=8 related to rural communities and communes which are at the same administrative level in Senegal. From rural communities limits, we will be able to determine bigger administrative entity, as arrondissement and departments.

Import will be done from each of the 3 shapefiles through JOSM :

  • Step 3, shapefile "Limite_Communauté_Rurale" (type polygone) : these are the rural communities, after cleaning data by deleting doubloons and merging/splitting ways, we'll
    • tag each way with
      boundary=administrative,
      admin_level=8, if the way belongs to an other administrative boundary (Saint-Louis region for example), the value associated to admin_level=* must be the lowest level,
      source=ARD_STL;CSE in agreement with the data donor, exception could be observed in conflation situation with existing data, see below Import_SEN_ARD-STL_CSE_Saint-Louis#Conflation
    • use a relation
      type=boundary to group together the ways forming the boundary (role:none) and the node symbolizing the administrative center (role:admin_center) added in the step 2.
      The relation will be tagged with
      boundary=administrative,
      admin_level=8,
      name=* and
      source=ARD_STL;CSE in agreement with the data donor
      .
    • as said before : from rural communities limits, we will be able to determine bigger administrative entity, as arrondissements, departments and region of Saint-Louis.

Changeset Tags

We will use the following changeset tags.

Data Merge Workflow

Approach

The importation is prepared and will be done by augustind with the support of HOT. The original authorization given by ARD Saint-Louis is held by Augustin Doury and a copy is avaible here

References

The import will be discussed in the import list.

Workflow

Following the three steps described above, each shapefile will be opened with JOSM. Original attributes will be changed in agreement with Import_SEN_ARD-STL_CSE_Saint-Louis#Tagging_Plans above.

  • shapefile "communes" and "Chefs-Lieux_de_CR" (type point) : if some communes or rural communities admin center already exist in OSM, be sure that the node is well located (in the center or the residential area using Bing Imagery) and well tagged (in agreement with Import_SEN_ARD-STL_CSE_Saint-Louis#Tagging_Plans.
  • shapefile "Limite_Communauté_Rurale" (type polygone) : each rural community is delimited by a closed-way, some ways must be merged inside the shapefile, at the junction between two rural comunities for example. Considering boundaries from the shapefile and from OSM, some ways must be merged, notably because of some rural communities boundaries (from shapefile) are joint with the national border (from OSM).

Save the file before uploading and upload.

Reverse plan

In case of any trouble, JOSM reverter will be used.

Conflation

Considering Saint-Louis region, the only boundaries mapped are national border (wdb:source=CIA World database II - africa-bdy.txt - segment xx) and the joint borders of Louga region and Saint-Louis region (source=http://www.naturalearthdata.com/downloads/10m-cultural-vectors/10m-admin-1-states-provinces/).