Pour importer des données à l'aide de la section "Importer", vous devez d'abord choisir la "classe de données". La classe de données dans AccessMod définit à la fois le type de données (raster, vecteur ou table) et le type de contenu (par exemple, occupation du sol, population, ...). Cela permet à AccessMod de pré-remplir divers champs de texte dans l'interface utilisateur avec le type correct d'informations, ce qui empêche (dans de nombreux cas) les utilisateurs d'utiliser des jeux de données non appropriés pour les analyses.
Les différentes classes de données sont les suivantes (avec “(r)” = “raster”, “(t)” = “table” et “(v)” = “vecteur”):
Classe de données | Type de données | Contenu des données |
|---|---|---|
(r) dem | raster | modèle numérique d'altitude - DEM (voir Section 3.3.1.2) |
(r) occupation du sol | raster | occupation du sol (svoire Section 3.3.1.4) |
(r) occupation du sol fusionnée | raster | occupation du sol après le fusionnement avec le réseau routier et les couches de barrières (résultat de l'outil "fusionnement de l'occupation du sol" voir Section 5.5.2) |
(r) population | raster | distribution spatiale de la population cible (voir Section 3.3.1.3) |
(r) population résiduelle | raster | distribution spatiale de la population résiduelle (résultat de l'analyse de couverture géographique - voir Section 5.5.4) |
(r) priorité | raster | distribution spatiale des zones prioritaires utilisées dans l'analyse de la mise à l'échelle (voir Section 3.3.1.10) |
(r) exclusion | raster | zone(s) d'exclusion (voir Section 3.3.1.5) |
(t) exclusion | table | critères d'exclusion utilisés pendant l'analyse de la mise à l'échelle (résultats de l'analyse de la mise à l'échelle - voir Section 5.5.7) |
(t) occupation du sol | table | lien entre chaque occupation du sol et son étiquette correspondante (voir Section 3.3.1.4) |
(t) scénario | table | vitesse et mode de transport pour chaque classe de la couche d'occupation du sol fusionnée (voir Section 3.3.2.2) |
(t) capacité | table | types et capacités de couverture des nouvelles structures de santé à localiser pendant l'analyse de mise à l'échelle (voir Section 3.3.2.3) |
(t) pertinence | table | critères de pertinence utilisés pendant l'analyse de mise à l'échelle (résultats de l'analyse de la mise à l'échelle - voir Section 5.5.7) |
(v) barrière | vector | barrières aux movements (polygones, lignes, points) (voir Section 3.3.1.8) |
(v) route | vector | réseau routier, avec information sur les catégories de routes road network (voir Section 3.3.1.7) |
(v) structure | vector | localisations des structures de santé (points) (voir Section 3.3.1.6) |
(v) zone pour stat | vector | zones (polygones), généralement des unités administratives, utilisées pour extraire des statistiques lors de l'analyse de statistiques zonales (voir Sections 3.3.1.9 and 5.5.6) |
(v) exclusion | vector | zone(s) d'exclusion (polygones) dans laquelle aucun nouvelle structure de santé ne peut être localisée pendant l'analyse de la mise à l'échelle (voir Sections 3.3.1.5) |
Next, you are asked to provide a tag and to check the validation information for the data you are about to upload. Once all is good, the “Choose and import data" button will turn grey and you will be able to select the corresponding file(s).
Please look at the beginning of Sections 3.3.1 for more information regarding the file(s) that needs to be selected depending on the format used for geospatial data, and at the beginning of Section 3.3.2 for the list of tabular formats supported by AccessMod.
After the importation process, a window specific to the data format will appear:
- In the case of an upload of a vector or tabular data set, the window will either display a message indicating that the upload was done without any problem or an error message. Please address the issues reported in the error message when applicable. It is a good practice NOT to import twice a shape file that has the same filename during a given session, and this even if the tag is changed. In this case, it is better to first change the filename of the shape file before importing it
- In the case of an upload of a raster data set, the window will display some information on projection and resolution as shown in the following example:
The table in this window contains three rows:
- The first row of the table provides the resolution (in meters) and the projection parameters of your project before the data set is imported. These projection and parameters are set in the GRASS environment of AccessMod and conditions all results in your project (i.e. all output raster data sets will adhere to these resolution and projections). The number and type of the projection parameters come directly from the GRASS environment and can differ from one projection to another. In the example above, one can see that the projection is UTM ("+proj=utm"), the UTM zone is 36 ("+zone=36"), and the projection is a metric one ("+to_meter=1")
- The second row of the table provides the same information after importation. In most cases, these should be identical to the first line, and therefore confirm that there have been no changes. In the case where you import a new DEM in your project with a different resolution than the original DEM, you will see here a different resolution in the second line, which implies that the resolution of your project has now changed and that all output raster created in any subsequent analysis will have this new resolution. This implies that all the previously imported raster format layer will be resampled according to the resolution of the new imported DEM. This operation might generate discrepancies an and errors in output. The recommended approach if you modify your DEM is to also adjust all the raster format layers in a GIS software for all of them to be consistent with the new DEM (projection, resolution, snapping) before re-importing them in AccessMod.
- The third row of the table provides the resolution and projection parameters of the data sets that you have imported. In this line, the way the projection parameters are indicated might differ slightly compared to the first two lines. This is due to the function AccessMod is using to fetch this information from within R-Shiny (in this case the projection information function from the "gdal" library, and not from the GRASS library as in the first two rows of this table). You can see this difference in the screenshot above, although the imported data set has got the same projection parameters as the project. The information reported here should correspond to those attached to your data set before the importation. A different set of information on the projection parameters means that GRASS has modified the dataset on the fly (i.e. automatically), which can create discrepancies in the results. In this case, we recommend to modify the layer to match the specification of the project inside a GIS software and to re-import the modified layer into AccessMod.
In future versions of AccessMod, the intent is to develop an advanced projection verification module that should be able to warn the user if there is any important mismatches among the imported data sets in term of resolution and projection.