Europe_map

I am working on software to automatically draw maps of regions of Europe. The aim is to be able to quickly create maps, mainly intended for illustrating articles about place-names.

These are my working principles:

• all-python code for ease of use and portability
• only public-domain sources of data to be used:
  1. altitude data at half-minute latitude-longitude resolution from National Geophysical Data Centre. I have packed each datum into one byte to speed up drawing. This gives a 20 metre altitude resolution.
  2. town and city locations from geonames. I have converted these to python dictionaries.
• high quality pdf (vector graphics) generation for publications; lower quality png (bitmap graphics) generation for webpages and casual viewing
• automatic altitude shading
• automatic labelled mercator grid lines
• names automatically moved to avoid collisions
• names in italics (with '/name') or (to do) bold ('*name')
• aspect ratio automatically adjusted to minimize map distortion
• several levels of usage:
  1. at the highest level, some utility programs are provided e.g. to search for names in a text file, look up their locations in a database (UK only at present) and plot them; or to search a text file for names closely followed by latitude, longitude pairs and plot them. A suitable bounding region will be worked out.
  2. at the middle level, the user just provides a list of names and locations in latitude, longitude format.
  3. at the lowest level, the user opens a map (specifying the region of interest), draws points and text on it, adds altitude coloring, etc.

Altitude coloring is tricky - a good trade-off between visual attractiveness and clarity is hard to achieve. Also, we want to keep colors light to save toner when printing maps. I am still working on this. Apart from this, the software is ready to be released soon.

example 00

The simplest possible map - just create a python dictionary with names and latitude,longitude pairs, and call Europe_map_from_dict. Map limits will be automatically adjusted. png and pdf output files are made, their names being formed by adding .png and .pdf to the given filename stem.

from europe_map import Europe_map_from_dict Europe_map_from_dict({ 'London': (51.5086,-0.1264), 'Paris' : (48.8529,2.3491) },fn='example_00',fontsize=18)
png  pdf

If your names and latitude,longitude pairs are in a tab-separated text file, you can create the dictionary something like this:

d=dict([tuple(i.split('')) for i in file('file.txt','r').read().split('\n')])

example 01

A bit more complex - more places. Note that starting a name with '-' causes it to be placed on the left of its dot, and starting with '|' puts the name in gray. A list of obscure places is given by a dictionary of grid references. Two big places are looked up from the database in the package.

from europe_map import Europe_map_from_dict, uk_place_dict sef_ngs={ 'Seave Close':'SE 474 556', 'Seave Green':'NZ 563 001', 'Seaves':'SE 585 715', 'Fleet Seaves':'SE 175 705', 'Seavy Dub':'NY 049 203', 'Seavy Man':'NY 786 014', 'Seavy Pond':'SE 832 935', 'Seavy Carr Wood':'SE 481 412', '-Seavy Carr':'SE 796 300', 'Seavy Rigg':'NY 814 181', } sef_ngs['|Liverpool']=uk_place_dict['Liverpool'][0] sef_ngs['|York']=uk_place_dict['York'][0] Europe_map_from_dict(sef_ngs,mxht=2000.0,fn='example_01',copyright='Keith Briggs')

png  pdf

example 02

from europe_map import Europe_map_from_dict Europe_map_from_dict({ "Land's End": 'SW 342 252', "John o'Groats": 'ND 381 726', "Lowestoft": 'TM 545 9256', "Belleek": (54.473,-8.101), }, fn='example_02',grayscale=True)
png  pdf

example 10

Low level usage - all information entered by hand. Notice that the name "Greenwich" is moved to avoid a collision with "London". This is done by default to all names.