TITLE: Geo-referenced Teixeira (1968) Bicuar National Park
vegetation map
DATE: 2023-06-01
AUTHOR: John L. Godlee
====================================================================
In a previous post I mentioned that I had been given a copy of J.
B. Teixeira's 1968 vegetation map of Bicuar National Park.
I just finished geo-referencing and vectorising the map, so I've
uploaded it here in case anybody wants to use it.
[uploaded it
here](
https://johngodlee.xyz/files/teixeira_georef/teixeira_1968_bic
uar_veg_map.zip)
The geo-referencing process was difficult, and the result isn't
perfect. The only clear reference points on the map that are
comparable with modern maps are the Cunene river and the locations
of the towns of Mulondo and Folgares (now Capelongo). The river
appears to have changed its course slightly since 1968, which is
plausible, as has the centre of the town of Folgares, where new
building has shifted away from the original colonial centre. The
outline of the Park is different now, having been redrawn in 2012,
notably reducing the size of the Park from the northern boundary.
The locations of the mulolas (seasonally flooded grassy valley
bottoms) are largely the same, and can be lined up with true colour
satellite imagery.
I used QGIS for all of the digitising process, drawing polygons by
hand. I then spent some time fiddling to adjust some polygons with
holes. I learned a lot about the "snapping" functionality in QGIS,
to avoid adjacent polygons with tiny gaps between them.
I used mapshaper to clean up the polygons further, using the clean
command in the console. This command repairs various abnormal
geometries, e.g. overlaps, small gaps, self-intersections, and
orphaned nodes. Then I took the shapefile back into QGIS for a few
minor manual adjustments.
[mapshaper]:
https://mapshaper.org/
I labelled the polygons according to the legend in the original
report.
[original
report](
https://johngodlee.xyz/files/teixeira_bicuar/teixeira_1968_b
icuar_veg_map.pdf)
