On the way to discover the analogy of the common desktop GIS procedures to Python we assumed that the process of extracting contours from raster was well documented or there were many tutorials on the topic. We found that there weren't many options to complete this process successfully or with few amount of pain, therefore we have done a complete tutorial on the process to create contours from a elevation raster with Python and GDAL that includes input data, scripts, and a discussion over the main steps of processing.

Under the concept of “Python spatial” we have developed a tutorial for the spatial processing of multiple bands from a Sentinel 2 image. The tutorial shows the procedure to read the set of bands, import a shapefile, clip each band and export the clipped version in another folder. The spatial process is independent from raster resolution and can be easily modified for Landsat images.

There are many ways to display spatial data, from the traditional maps, GIS desktop software and most recently on the web. We face certain challenges to display spatial data on the web because we will require certain functionalities that we find on a desktop software and certain spatial analysis tools implemented as buttons. Django is a web framework written in Python that allows to create web applications with moderate simplicity and this framework is capable of displaying vector spatial data using libraries such as Folium.

We have created a tutorial with an applied case of displaying hydrological spatial information on a webapp in Django. The tutorial creates a Django project, creates an app for the spatial data representation, imports the vector data (geojson or shp) and displays spatial data with defined styles.

OpenDroneMap is such a great software for its capabilities to spatially process drone image and create a complete set of outputs as digital elevation model, point clouds, orthophotos and others. For regular users, the installation and the computational resources have allways been a challenge. This time we have develop a succesful procedure to install and run OpenDroneMap in Windows 10 by installing a Ubuntu 18.04 subsystem.

When working with satellite imagery we have to take into account the spatial and temporal scale. The selection and processing of remote sensing data products on a specific area over a certain period of time requires a great amount of time and computational resources. We have explored the web application AppEEARS from the USGS to download land cover images (MCD12Q1v006) over a specific area and time range. The tutorial covers all the steps from creating a polygon in QGIS3 as Geojson, upload into the webapp, the subsequent instructions to download the files, displaying the data in QGIS3 and review the pixel values correspondances.

Spatial information is linked to the position and a system of reference. There are many coordinate systems worldwide with different length units, projections and origins. Somehow, spatial analysis is always linked to information stored on different coordinate systems and we have to provide effective ways to translate them to a specific CRS (coordinate reference system).

We have developed a tutorial for the coordinate system translation of XY point location stored in tables. The tutorial shows the procedure to change coordinate systems from geographic and planar coordinates using the Pyproj library over a Pandas dataframe on a Jupyter notebook.

So far, OpenDroneMap is a strong open source alternative for the processing of drone imagery. We have done a recursive analysis over a set of aerial photos on a standard desktop computer to have a panorama of the rates and trends from OpenDroneMap in the computation of different amount of images. Although the rates and trends apply only for a specific dataset and computer configuration, this study can to be taken as a reference for the computational time and as a perspective of how the software works with great amount of data.

The problems and challenges in water resources management, the environment protection, risk prevention and many subjects related to the human activity require transmitting data in a practical and updated way. The web maps are a good solution since many of these data are associated to a location and the Internet is a great tool available for many. The development of web maps is relatively new but necessary to implement for many uses like data diffusion, the understanding of problematic and decision making.