26 Sep 2014

Make a KML-File from an OpenStreetMap Trail

Ever wished to use a trail on OSM on your GPS or smartphone? With this neat little R-Script this can easily be done. You'll just need to search OpenStreetMap for the ID of the trail (way), put this as argument to osmar::get_osm, convert to KML and you're good to go!




# get OSM data
library(osmar)
library(maptools)
  
rotewandsteig <- get_osm(way(166274005), full = T)
sp_rotewandsteig <- as_sp(rotewandsteig, what = "lines")
  
# convert to KML 
kmlLine(sp_rotewandsteig@lines[[1]], kmlfile = "rotewandsteig.kml",
        lwd = 3, col = "blue", name = "Rotewandsteig") 

# view it
shell.exec("rotewandsteig.kml")

14 Jul 2014

Custom Feature Edit Forms in QGIS with Auto-Filling Using PyQt

For anyone interested in the capabilities of customized feature edit forms in QGIS I'd like to reference the following GIS-Stackexchange posting: http://gis.stackexchange.com/questions/107090/auto-populate-field-as-concatenation-of-other-fields

Quick GIS-Tip: Permanentely Sort Attribute Table by Attribute

Here's a short shell-script (I have C:\OSGeo4W64\bin\ on my PATH) for sorting GIS data, a sqlite-db in this case, and saving it in the newly created order to a file. The DB is sorted in ascending order by the attribute 'Name' and written to a file with the KML Driver.

cd C:/Users/Kay/Documents/Web/Openlayers/Docs/Digitizing
ogr2ogr -sql "SELECT * FROM 'trails-db' ORDER BY Name ASC" -f "KML" trails.kml trails.sqlite