April 11, 2017

What data do you need for hydrogeological modeling?

April 11, 2017/ Saul Montoya

A hydrogeological evaluation needs a numerical representation of the groundwater flow regime. Numerical models are a great tool to evaluate the current and future conditions of groundwater flow. In order to make a model, it is necessary to have geological and climate data, among other types.

The following list describes the input data needed to carry out a hydrogeological modeling. The information required could be either in tabular or vectorial format.

April 11, 2017

Working with Sentinel 2 Imagery on QGIS

April 11, 2017/ Saul Montoya

Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator (source ESA).

This is a group of videos called "Working with Sentinel 2 Imagery on QGIS" that shows the complete procedure to download, represent and process Sentinel 2 images in QGIS.

April 11, 2017

How to create contours from a Raster File - Example on a NDVI Layer

April 11, 2017/ Saul Montoya

This tutorial show the procedure to create contours from a raster file considering interval definition. The example is made from a NDVI raster file.

April 11, 2017

How to cut a Raster File on QGIS - Example on a NDVI Layer

April 11, 2017/ Saul Montoya

This tutorial show the procedure to cut a NDVI Raster File calculated from a Sentinel 2 Granule on QGIS.

April 11, 2017

Cost (& Time) optimization of hydrogeological studies

April 11, 2017/ Saul Montoya

Impact on groundwater flow from mining facilities could be evaluated many times along the different mining phases, many of these evaluations are done by different consultant companies. This post is focused on strategies and best practices for cost (& time) optimization, specially for hydrogeological investigation on mining projects.

April 11, 2017

How to calculate the NDVI Index from a Sentinel 2 Image

April 11, 2017/ Saul Montoya

This tutorial show the prodecure to calculate the NDVI from Sentinel 2 bands on QGIS.

April 11, 2017

How to represent Sentinel 2 Bands in a False Color Image with QGIS

April 11, 2017/ Saul Montoya

False color images are used to enhance certain cover types as vegetation on the image representation. This tutorial show the procedure represent the bands of a False Color image from Sentinel 2 bands in QGIS.

April 11, 2017

How to represent Sentinel 2 Bands in a True Color Image with QGIS

April 11, 2017/ Saul Montoya

This tutorial show the procedure represent the bands of a Sentinel 2 Granule (Image) in QGIS. The representation of the image is True Color (Red, Green and Blue)

April 11, 2017

How to Create River Geometry for HEC-RAS using Q-RAS

April 11, 2017/ Saul Montoya

In order to make a hydraulic modeling with HEC-RAS, one of the most important input data needed is the river and cross sections geometry. However this data is not always available.

In this opportunity we want to present a QGIS complement called Q-RAS that, in a very simple way, creates the geometry data using a DEM file.

April 11, 2017

Importance of numerical modeling

April 11, 2017/ Saul Montoya

In the actual society, the environmental aspects are a concern when planning projects related to water resources. In this context, numerical models are useful tools to represent the superficial water and groundwater cycle and determine the contamination effects.

April 11, 2017

How to make a map with QGIS - VIDEO

April 11, 2017/ Saul Montoya

Interesting tutorial that explains how to make a map with QGIS.

April 07, 2017

How many Spectral Bands have the Sentinel 2 Images?

April 07, 2017/ Saul Montoya

The Sentinel 2 satellites have a Multi-Spectral Instrument (MSI) with 13 spectral bands that range from the visible range to the shortwave infrared (SWIR). Bands come in variable resolutions from 10 to 60 meter and their wavelenght is determined based on specific purposes.

April 07, 2017

How to Calculate NDVI Using Landsat 8 Images and QGIS

April 07, 2017/ Saul Montoya

The NDVI (Normalized Difference Vegetation Index) is a versatile vegetation index to evaluate the vegetation and dynamic of the vegetation coverage change. This index has been studied and evaluated with many satellites over the years, changing its calculus method in relation to the number and type of bands of the satellite. The following tutorial shows the NDVI calculus for Landsat 8 images using QGIS.

April 07, 2017

8 Hydrogeology Books You Should Know About

April 07, 2017/ Saul Montoya

If you need hydrogeology bibliography that includes topics like modeling, groundwater quality and remediation, the options are scarce. In this article we will show 8 excellent and recent groundwater books and a summary about them.

The following books have been bought by the author in bookstores or through websites. They all are in English and are in no particular order.

April 07, 2017

How to Download Specific Granules from ESA Sentinel 2 Images

April 07, 2017/ Saul Montoya

This tutorial show the procedure to download especific granules from a ESA Sentinel 2 Image using the website: https://scihub.copernicus.eu/

April 07, 2017

How to Download ESA Sentinel 2 Satellite Images

April 07, 2017/ Saul Montoya

This tutorial show the procedure to download images of ESA Sentinel 2 from the website: https://scihub.copernicus.eu/

April 06, 2017

How to import spreadsheet data into QGIS

April 06, 2017/ Saul Montoya

One of the most common tasks when working with Geographic Information Systems (GIS) is the representation of points from a spreadsheet to a shapefile. Here, we will explain the steps to achieve this.

April 06, 2017

Evaporation and Homogeneous Redox Reactions Simulation with Phreeqc

April 06, 2017/ Saul Montoya

Evaporation is accomplished by removing water from the chemical system. Water can be removed as an irreversible reactant with a negative reaction coefficient in the REACTION keyword input. This example uses this method; the REACTION data block is used to simulate concentration of rain water by approximately 20 fold by removing 95 percent of the water. The resulting solution contains only about 0.05 kg of water. In a subsequent simulation, the MIX keyword is used to generate a solution that has the same concentrations as the evaporated solution, but has a total of mass of water of approximately 1 kg.

April 06, 2017

How to make an Environmental Impact Assessment (EIA) using only Open Source software?

April 06, 2017/ Saul Montoya

The study of the environment, the understanding of the water cycle / atmospheric processes and the interaction with the aquatic and terrestrial ecosystems need advanced analysis tools. It is important to understand how the environment works and the potential impacts of our actions in the future. This goes further than a regulatory approach, we need a constant search and evolution of codes and models and this is where open source software has important advantages.

This article shows the most important open source software that can be used to make the different sections of an EIA.

April 06, 2017

5 QGIS plugins you should know about

April 06, 2017/ Saul Montoya

QGIS development in the past years has been impressive for an open source software. The current version is 2.18 Las Palmas. Each version is better than the previous one when it comes to functionalities, amount of tools, and bug fixing. In my opinion, for an intermediate QGIS user, the amount of new tools are bigger than the ability to learn them. Being up to date with the latest QGIS characteristics requires quite some time.