Making arty renders of Belize's rivers

DATE: 2018-07-01
AUTHOR: John L. Godlee


y partner spends a lot of time in Belize for work and was looking for something to hang on her wall as a piece of art. I thought that a stylised map of Belize could make a nice minimalist piece of art, but because I have no artistic skills, I decided to do it using R.

I got some shapefiles to start with:

• A simple global river bankfull width and depth database[1] - For the rivers
• GADM Data[2] - Outline of Belize

I also experimented with other shapefiles of rivers in Belize, but the one above is the one I preferred, mainly because it has slightly angular lines. These are the other sources I looked at:

1: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/wrcr.20440 (https://agupubs.onlinelibrary.wiley.com)
2: https://gadm.org/download_country_v3.html (https://gadm.org)

• Meerman 2015[3]
• Digital Chart of the World - Inland Water[4]

Map comparison (https://johngodlee.xyz)

3: http://www.biodiversity.bz/ (http://www.biodiversity.bz)
4: http://www.diva-gis.org/gdata (http://www.diva-gis.org)

Here is the R code that I used to create the map output. I saved it as an svg for printing and also as a png for previewing:

# Packages ----
library(rgdal)
library(raster)

# Add shapefiles ----
belize <- readOGR(dsn = "BLZ_adm", layer = "BLZ_adm0")

rivers_1 <- readOGR(dsn = "camerica", layer = "carivs")

rivers_2 <- readOGR(dsn = "Belize_Rivers 2", layer = "Belize_Rivers")

rivers_3 <- readOGR(dsn = "BLZ_wat", layer = "BLZ_water_lines_dcw")

watersheds <- readOGR(dsn = "Belize_Watersheds", layer = "Belize_Watersheds")

# Fix shapefiles ----

## Transform rivers_2 to wgs84 CRS
rivers_2_wgs84 <- spTransform(rivers_2, CRS("+proj=longlat +datum=WGS84 +no_defs +ellps=WGS84 +towgs84=0,0,0"))

# rivers_1 ----

## Filter out rivers not in Belize
rivers_1_belize <- crop(rivers_1, belize)

## Save as .svg
svg(filename = "img/svg/rivers_1_belize.svg", width = 15, height = 20, onefile = TRUE)
plot(rivers_1_belize)
plot(belize, add = TRUE)
dev.off()

## Filter out small rivers according to bank full width
rivers_1_big <- rivers_1_belize[rivers_1_belize$a_WIDTH > quantile(rivers_1_belize$a_WIDTH, 0.50), ]

## Save as .svg
svg(filename = "img/svg/rivers_1_big.svg", width = 15, height = 20, onefile = TRUE)
plot(rivers_1_big)
plot(belize, add = TRUE)
dev.off()

# rivers_2 ----

## Filter streams that are more than 2nd order, or 3rd order
rivers_2_first <- rivers_2_wgs84[rivers_2_wgs84$Strm_order > 1, ]
rivers_2_second <- rivers_2_wgs84[rivers_2_wgs84$Strm_order > 2, ]

## Crop to belize outline
rivers_2_first_belize <- crop(rivers_2_first, belize)
rivers_2_second_belize <- crop(rivers_2_second, belize)

## Write as shapefiles because the cropping took a long time
writeOGR(obj=rivers_2_first_belize, dsn="belize_rivers_2_first_crop", layer="belizer_rivers_2_first_crop", driver="ESRI Shapefile")
writeOGR(obj=rivers_2_second_belize, dsn="belize_rivers_2_second_crop", layer="belizer_rivers_2_second_crop", driver="ESRI Shapefile")

## Save as .svg
svg(filename = "img/svg/rivers_2_wgs84.svg", width = 15, height = 20, onefile = TRUE)
plot(rivers_2_wgs84)
plot(belize, add = TRUE)
dev.off()

svg(filename = "img/svg/rivers_2_first_belize.svg", width = 15, height = 20, onefile = TRUE)
plot(rivers_2_first_belize)
plot(belize, add = TRUE)
dev.off()

svg(filename = "img/svg/rivers_2_second_belize.svg", width = 15, height = 20, onefile = TRUE)
plot(rivers_2_second_belize)
plot(belize, add = TRUE)
dev.off()

# rivers 3 ----

## Save as .svg
svg(filename = "img/svg/rivers_3.svg", width = 15, height = 20, onefile = TRUE)
plot(rivers_3)
plot(belize, add = TRUE)
dev.off()

I'm printing off the big file next week, then I want to frame it in a thin black edge frame with glossy glass.

Best map (https://johngodlee.xyz)