SArDeGnA (SpAtial Data Grid frAmework)

• SArDeGnA is a lightweight framework to manage spatial data in Python using a grid approach.
• This framework can help you to manage Point of Interests (i.e. pubs, restaurant) or points related to trajectories.
• An example of a grid created with SArDeGnA and imported in Google Maps as KML file :

• Full Google map

The Design Principle: A Spatial Grid in 1 line of code!

• The framework has a set of classes and related functions useful to create a grid to organize your spatial data.

• You can create a grid in just one line of code! :

 Grid().create_grid([lng_center, lat_center, radius_center], radius_cell)

- lng_center is the center of the grid specified in longitude
- lat_center is the center of the grid specified in latitude
- radius_center is the radius of the grid
- radius_cell is the radius of the cell within the grid

• Then, you have a set of primitives that will help you to manage the POI within the grid.

Dependencies

• Python 3.*

• Libraries in requirements.txt:

 pip install -r requirements.txt

• GDAL - Geospatial Data Abstraction Library (GDAL2).

• Python Binding for GDAL

• In Mac, it will prefer to use brew as follow :

 brew install gdal2 --HEAD

• "--HEAD" to install the header
• For Linux and Microsoft, you can google : ) : install GDAL2
• Some good links for installing GDAL in Windows are :
  • https://www.gis.usu.edu/~chrisg/python/2009/docs/gdal_win.pdf
  • https://stackoverflow.com/questions/33574902/install-gdal-using-conda ( based on Conda )
• For MAC, I found useful to run:

brew update && brew upgrade

• Note that in order to install the python binding, first check the version of installed GDAL:

(spatial-data-analysis) AMAC02RF28MG8WN:spatial-data-framework antonio.penta$ ogr2ogr --version
GDAL 2.4.0, released 2018/12/14

• Then, you can run the following pip install (be sure the virtual env is activated, and you are using the pip of your virtual env):

pip install pygdal=="`gdal-config --version`.*"

• The above line has been suggested (here)[https://github.com/nextgis/pygdal/tree/master/2.2.4]

• If the installation of GDAL is ok, you should be able to run successfully the following import in your python console:

from osgeo import gdal

• In my case, I have:

(spatial-data-analysis) AMAC02RF28MG8WN:spatial-data-framework antonio.penta$ python
Python 3.6.3 (default, Oct  4 2017, 06:09:05)
[GCC 4.2.1 Compatible Apple LLVM 8.0.0 (clang-800.0.42.1)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> from osgeo import gdal
>>> exit

Virtualenv

• SArDeGnA uses the virtual env descrebed in requirements.txt file, so you need to incorporate it in your env:

pip install -r requirements.txt

Jupyter with Ipyleaflet extension to visualize the maps

• The attached Jupyter Notebook is using extension ipyleaflet to visualize the map.
• My suggestion is to install ipyleaflet downloading the latest development from GitHub (requires npm installed):

$ git clone https://github.com/jupyter-widgets/ipyleaflet.git
$ cd ipyleaflet
$ pip install -ee .
$ jupyter nbextension install --py --symlink --sys-prefix ipyleaflet
$ jupyter nbextension enable --py --sys-prefix ipyleaflet

Jupyter Notes

** Be sure to use ipython and jupyter from your virtual env **

• Be sure that the virtual env has the GDAL binding,

• To check if Jupyter notebook is using the right env, you can print the sys.path and check the path:

import sys
print(sys.path)

• Be sure to have the Ipyleaflet extension (session above)

• To enable that Jupyter notebook use your virtual env instructions here under the Installation session, ensuring to lunch 'jupyter labextension .. ' as '/path_your_env/jupyter labextension .. '

• In my case, first I activate the virtual env used for this project, then I run:

pip install ipykernel
ipython kernel install --user --name=sardegna

Tutorial

• Lunch the jupyter pointing to the main folder:

 ~/Documents/virtualenv/sardegna/bin/jupyter notebook --notebook-dir=./

Donations

• If you found this code useful, please condider to make a donation to AVSI
  • https://www.avsi.org/en/country/
  • http://www.avsi-usa.org/donate.html
  • https://www.avsi.org/it/donation/

Many thanks!

Authors

Antonio Penta