Madagascar Population Map Metadata Report

Prediction Weighting Layer Used in Population Redistribution

The data presented below represent the predicted number of people per ~100 m pixel as estimated using the random forest (RF) model as described in Stevens, et al. (2015). The following pages contain a description of the RF model and its covariates, their sources and any metadata collected for each covariate. The prediction weighting layer is used to dasymetrically redistribute the census counts and project counts to match estimated populations based on UN estimates for the final population maps provided by WorldPop.

Different RF models were combined to produce the final output: a nation-wide model and specific models for some cities. City-specific models for Antananarivo and Toasmina are described in separated metadata files. Output maps were mosaicked to obtain one consistent nation-wide map.

Stevens, F. R., Gaughan, A. E., Linard, C., & Tatem, A. J. (2015). Disaggregating Census Data for Population Mapping Using Random Forests with Remotely-Sensed and Ancillary Data. PLOS ONE, 10(2), e0107042. doi:10.1371/journal.pone.0107042

plot of chunk predict_density

Madagascar Census Data and Observed Population Density

These data are the population density values used to estimate the RF model used to create the prediction weighting layer you see above. Values represent population density as measured by people per hectare and calculated from population counts within each census unit. These values are used as the dependent variable during model estimation.

Madagascar Census Data, 2006, Admin-level 2

Folder: Census
File Name: MDG_adm4_2006.shp
Source: Estimates derived from RGPH (Recensement Général de la Population et de l'Habitat) 1993, Institut National de la Statistique, Madagascar
Description: These census data were extracted from GeoHive (www.geohive.com). Required fields for map production are ADMINID and ADMINPOP.
Class: polygon
Derived Covariates:
area, buff, zones,

class       : SpatialPolygonsDataFrame 
nfeatures   : 17459 
extent      : 311938, 1089711, 7167963, 8675263  (xmin, xmax, ymin, ymax)
coord. ref. : NA 
nvariables  : 22

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Random Forest Model and Diagnostics

These output and figures outline the estimated RF model that is used to predict the population density weighting layer. The model is fitted to the population density values for the preceding census data using covariates aggregatedfrom the ancillary data sources summarized following the model diagnostics.


Call:
 randomForest(x = x_data, y = y_data, ntree = popfit$ntree, mtry = popfit$mtry,      nodesize = length(y_data)/1000, importance = TRUE, proximity = TRUE) 
               Type of random forest: regression
                     Number of trees: 500
No. of variables tried at each split: 22

          Mean of squared residuals: 0.44
                    % Var explained: 86

plot of chunk random_forestplot of chunk random_forest

Error: negative extents to matrix

Covariate Metadata

Folder: Landcover
File Name: mdg_lc.tif
Source:
Description:
Class: raster
Derived Covariates:
cls011, dst011, cls040, dst040, cls130, dst130, cls140, dst140, cls150, dst150, cls160, dst160, cls190, dst190, cls200, dst200, cls210, dst210, cls230, dst230, cls240, dst240, cls250, dst250, clsBLT, dstBLT,

class       : RasterBrick 
dimensions  : 15210, 7952, 120949920, 1  (nrow, ncol, ncell, nlayers)
resolution  : 100, 100  (x, y)
extent      : 302929, 1098129, 7157914, 8678914  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 
data source : D:\APRF\RF\data\MDG\Landcover\Derived\landcover.tif 
names       : landcover 
min values  :        11 
max values  :       250 

plot of chunk covariate_reports


Suomi NPP VIIRS-Derived 2012 Lights at Night, 15 arc-second

Folder: Lights
File Name: DEFAULT: VIIRS 2012
Source: http://ngdc.noaa.gov/eog/viirs/download_viirs_ntl.html
Description: These 'Lights at Night' data were derived from imagery collected by the Suomi National Polar-orbiting Partnership (NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) sensor. Data were collected in 2012 on moonless nights and though background noise associated with fires, gas-flares, volcanoes or aurora have not been removed it represents the best-available data for night-time light production.
Class: raster
Derived Covariates:
,

class       : RasterBrick 
dimensions  : 15210, 7952, 120949920, 1  (nrow, ncol, ncell, nlayers)
resolution  : 100, 100  (x, y)
extent      : 302929, 1098129, 7157914, 8678914  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 
data source : D:\APRF\RF\data\MDG\Lights\Derived\lights.tif 
names       : lights 
min values  :  -0.16 
max values  :    523 

plot of chunk covariate_reports


WorldClim/BioClim Mean Annual Temperature 1950-2000, 30 arc-second

Folder: Temp
File Name: DEFAULT: BIO1
Source: http://www.worldclim.org/current
Description: WorldClim/BioClim 1950-2000 mean annual precipitation (BIO12) and mean annual temperature (BIO1) estimates (Hijmans et al., 2005) were downloaded, mosaicked and subset to match the extent of our land cover data for the mapping of this region.
Class: raster
Derived Covariates:
,

class       : RasterBrick 
dimensions  : 15210, 7952, 120949920, 1  (nrow, ncol, ncell, nlayers)
resolution  : 100, 100  (x, y)
extent      : 302929, 1098129, 7157914, 8678914  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 
data source : D:\APRF\RF\data\MDG\Temp\Derived\temp.tif 
names       : temp 
min values  :  110 
max values  :  276 

plot of chunk covariate_reports


WorldClim/BioClim Mean Annual Precipitation 1950-2000, 30 arc-second

Folder: Precip
File Name: DEFAULT: BIO12
Source: http://www.worldclim.org/current
Description: WorldClim/BioClim 1950-2000 mean annual precipitation (BIO12) and mean annual temperature (BIO1) estimates (Hijmans et al., 2005) were downloaded, mosaicked and subset to match the extent of our land cover data for the mapping of this region.
Class: raster
Derived Covariates:
,

class       : RasterBrick 
dimensions  : 15210, 7952, 120949920, 1  (nrow, ncol, ncell, nlayers)
resolution  : 100, 100  (x, y)
extent      : 302929, 1098129, 7157914, 8678914  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 
data source : D:\APRF\RF\data\MDG\Precip\Derived\precip.tif 
names       : precip 
min values  :    331 
max values  :   3373 

plot of chunk covariate_reports


Protected Areas

Folder: Protected
File Name: DEFAULT: WDPAfgdb_Sept2012.gdb
Source: World Database on Protected Areas, Downloaded September, 2012, UNEP, http://www.wdpa.org, http://protectedplanet.net
Description: These data are compiled by UNEP and distributed via the Protected Planet website. All protected areas were downloaded regardless of International Union for Conservation of Nature (IUCN) or any other designation, so they include sanctuaries, national parks, game reserves, World Heritage Sites, etc.
Class: polygon
Derived Covariates:
cls, dst,

class       : SpatialPolygonsDataFrame 
nfeatures   : 106 
extent      : 306562, 1088112, 7167617, 8644095  (xmin, xmax, ymin, ymax)
coord. ref. : NA 
nvariables  : 27

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Urban Extents

Folder: Urban
File Name: DEFAULT: schneider-urban.shp
Source: Schneider, et al., United Nations
Description: These data were constructed from MODIS-derived imagery and provided to WorldPop researchers by Schneider, et al. as part of a global urban extents datasets.
Class: polygon
Derived Covariates:
cls, dst,

class       : SpatialPolygonsDataFrame 
nfeatures   : 120 
extent      : 325024, 1070724, 7198180, 8639085  (xmin, xmax, ymin, ymax)
coord. ref. : NA 
nvariables  : 2

plot of chunk covariate_reports


Elevation and Derived Slope, 3 second

Folder: Elevation
File Name: DEFAULT: Void-Filled DEM.gdb
Source: HydroSHEDS Void-Filled DEM (Lehnert, et al., 2006), http://hydrosheds.cr.usgs.gov/dataavail.php
Description: The HydroSHEDS data are the result of an effort to provide a globally consistent dataset consisting of NASA's Shuttle Radar Topography Mission (SRTM) data and have been processed, void-filled and corrected for use at large scales.
Class: raster
Derived Covariates:
, slope,

class       : RasterBrick 
dimensions  : 15210, 7952, 120949920, 1  (nrow, ncol, ncell, nlayers)
resolution  : 100, 100  (x, y)
extent      : 302929, 1098129, 7157914, 8678914  (xmin, xmax, ymin, ymax)
coord. ref. : +proj=utm +zone=38 +south +datum=WGS84 +units=m +no_defs +ellps=WGS84 +towgs84=0,0,0 
data source : D:\APRF\RF\data\MDG\Elevation\Derived\elevation.tif 
names       : elevation 
min values  :       -27 
max values  :      2870