I need to plot more than 100 images for a specific area which are not included in default Basemap. I have read lot of documentation regarding speeding up the matplotlib/basemap plotting examples. Most of them lead to this example https://github.com/matplotlib/basemap/blob/master/examples/hires.py . I agree that picklling does improve the code for Basemap instance. However, I also required to read the shape file once the Basemap instance is created like following:-

south = 0
north = 5
west = 70
east = 85

following is a global instance and read once only

m = Basemap(projection='merc', llcrnrlat=south, urcrnrlat=north,
llcrnrlon=west, urcrnrlon=east, resolution='c')

the following line a part of plotting function and not a continuous line from above

m.readshapefile('data/gis-data/world_countries/ne_10m_admin_0_countries_lakes', 'ne_10m_admin_0_countries_lakes', linewidth=0.7)

Please see that I am reading shape file from NE 10 resolution file (~ 8 mb). When I read this shape file it takes about 10-15 sec which is too much for just map. This is a big problem as the code (m.readshapefile) reside inside the map plotting function and it has to be called to plot boundaries each time.

I have a question and a proposal (sort of) here.

Question:-
How to improve the plotting time by reducing the reading time of shape file using the default m.readshapefile code. There could be some solution similar to pickle which I am not aware. Best people can share their experience here (with some example code).

Proposal (sort of):-
The major problem with the reading shape file which I think is basemap reading the entire shapefile. Why should it read all the data from shapefile if you the lat/lon which are already specified in the basemap instance. Therefore, readshapefile should only read data within the lon/lat specified from the basemap instance. I hope that this way shapefile read time may be reduced greatly.

I may or may not be correct somewhere above. Forgive my ignorance. I hopr that some one may help me on reading shapefile/ plotting the map faster.

Note ::: Please don't suggest me to use lower resolution basemap/shapefile.