Leonardo Uieda- PhD
- Professor Doutor at University of São Paulo
Leonardo Uieda
- PhD
- Professor Doutor at University of São Paulo
About
68
Publications
21,473
Reads
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3,417
Citations
Introduction
I'm a geophysicist specializing in mathematical and computational methods for determining the inner structure of the Earth from physical observations, like disturbances in the Earth's gravity and magnetic fields. I work on a range of open-source software projects in Python and C, including Fatiando a Terra, Tesseroids, and PyGMT. I'm an advocate for open and reproducible practices in the science.
Current institution
Additional affiliations
August 2019 - July 2023
February 2017 - August 2019
February 2014 - February 2018
Position
- Professor
Description
- I'm responsible for the undergraduate Geophysics and Numerical Methods courses and the Laboratory of Exploration Geophysics (LAGEX). I'm currently on leave for a 1-2 year visiting researcher/postdoc position at the University of Hawaii.
Education
November 2011 - April 2016
March 2010 - October 2011
September 2008 - June 2009
Publications
Publications (68)
The first step in scientific data acquisition often involves analyzing entire samples, providing only a general characterization of the material. Enhancing data acquisition by improving spatial resolution and isolating the underlying phenomena contributing to the overall signal has become a central direction in various scientific fields. In paleoma...
Locating the sources of observed disturbances in potential-field data is a challenging problem due to the non-unique nature of the inverse problem. The Euler deconvolution method was created to solve this issue, particularly for idealized sources (such as spheres and planar vertical dykes). Euler deconvolution has become widely used in potential-fi...
Paleomagnetic data is collected from bulk samples, containing a mixture of stable and unstable magnetic particles. Recently, magnetic microscopy techniques have allowed the examination of individual magnetic grains. However, accurately determining the magnetic moments of these grains is difficult and time‐consuming due to the inherent ambiguity of...
The Generic Mapping Tools (GMT) software is ubiquitous in the Earth and Ocean sciences. As a cross‐platform tool producing high quality maps and figures, it is used by tens of thousands of scientists around the world. The basic syntax of GMT scripts has evolved very slowly since the 1990s, despite the fact that GMT is generally perceived to have a...
The equivalent source technique is a powerful and widely used method for processing gravity and magnetic data. Nevertheless, its major drawback is the large computational cost in terms of processing time and computer memory. We present two techniques for reducing the computational cost of equivalent source processing: block-averaging source locatio...
Potential field data often require interpolation onto a regular grid at constant height before further analysis. A widely used approach for this is the equivalent sources technique, which has been adapted over time to improve its computational efficiency and accuracy of the predictions. However, many of these approaches still face challenges, inclu...
Magmatic rocks record ambient magnetic fields during cooling, preserving them for billions of years through thermoremanent magnetization (TRM). TRM accuracy depends on particle size, shape, magnetic properties, and the number of particles available to record the field. While traditionally interpreted via Neél's single‐domain theory, most particles...
Magmatic rocks record ambient magnetic fields during cooling, preserving them for billions of years through thermoremanent magnetization (TRM). TRM accuracy depends on particle size, shape, magnetic properties, and the number of particles available to record the field. While traditionally interpreted via Neél’s single-domain theory, most particles...
PyGMT is a library for processing geospatial and geophysical data and making publication-quality maps and figures. It provides a Pythonic interface for the Generic Mapping Tools (GMT), a command-line program widely used across the Earth, Ocean, and Planetary sciences and beyond.
Earth scientists can estimate the depth of certain rocks beneath Earth's surface by measuring the small disturbances that they cause in the Earth's gravity and magnetic fields. A popular method for this is Euler deconvolution, which is widely available in geoscience software and can be run quickly on a standard computer. Unfortunately, Euler deconv...
PyGMT is a library for processing geospatial and geophysical data and making publication-quality maps and figures. It provides a Pythonic interface for the Generic Mapping Tools (GMT), a command-line program widely used across the Earth, Ocean, and Planetary sciences and beyond.
PyGMT is a library for processing geospatial and geophysical data and making publication-quality maps and figures. It provides a Pythonic interface for the Generic Mapping Tools (GMT), a command-line program widely used across the Earth, Ocean, and Planetary sciences and beyond.
PyGMT is a library for processing geospatial and geophysical data and making publication-quality maps and figures. It provides a Pythonic interface for the Generic Mapping Tools (GMT), a command-line program widely used across the Earth, Ocean, and Planetary sciences and beyond.
PyGMT is a library for processing geospatial and geophysical data and making publication-quality maps and figures. It provides a Pythonic interface for the Generic Mapping Tools (GMT), a command-line program widely used across the Earth, Ocean, and Planetary sciences and beyond.
Paleomagnetic data are usually obtained from whole cylindric samples, where the signal results from the sum of magnetic moments from hundreds of thousands to millions of magnetic particles within the sample volume. This usually includes both stable and unstable remanence carriers.Recently, magnetic microscopy techniques allowed the investigation of...
PyGMT is a library for processing geospatial and geophysical data and making publication-quality maps and figures. It provides a Pythonic interface for the Generic Mapping Tools (GMT), a command-line program widely used across the Earth, Ocean, and Planetary sciences and beyond.
<<< This paper has been submitted for publication in Geophysical Journal International. A preprint version is available on EarthArXiv. >>> We present the gradient-boosted equivalent sources: a new methodology for interpolating very large datasets of gravity and magnetic observations even on modest personal computers, without the high computer memor...
We present a new strategy for defining the location of point sources when
applying the equivalent sources technique (EQL) for interpolating gravity and
magnetic data. It consist in reducing the number of sources while keeping the
same accuracy when compared with similar EQL methods. It also reduces the
computation time and memory requirements, both...
Presented at EGU 2020 (online because of COVID-19), session "G4.3: Acquisition and processing of gravity and magnetic field data and their integrative interpretation". Details some of the work we've been doing in Verde and Harmonica for machine-learning style interpolation with equivalent-sources. In particular, applying state-of-the-art cross-vali...
Scientific software is usually created to acquire, analyze, model, and visualize data. As such,many software libraries include sample datasets in their distributions for use in documentation,tests, benchmarks, and workshops. A common approach is to include smaller datasets in the GitHub repository directly and package them with the source and binar...
We present a new methodology to compute the gravitational fields generated by tesseroids (spherical prisms) whose density varies with depth according to an arbitrary continuous function. It approximates the gravitational fields through the Gauss-Legendre Quadrature along with two discretization algorithms that automatically control its accuracy by...
OPEN ACCESS PREPRINT VERSION: https://doi.org/10.31223/osf.io/3548g -------------------
We present a new methodology to compute the gravitational fields generated by tesseroids (spherical prisms) whose density varies with depth according to an arbitrary continuous function. It approximates the gravitational fields through the Gauss-Legendre Quadra...
An efficient forward modeling algorithm for calculation of gravitational fields in spherical coordinates is developed for 3‐D large‐scale gravity inversion problems. The 3‐D Gauss‐Legendre quadrature (GLQ) is used to calculate the gravitational fields of mass distributions discretized into tesseroids. Equivalence relations in the kernel matrix of t...
Abstract submitted to LAPIS 2019: Inverse methods in Geophysics.
We introduce a novel methodology for gravity forward modeling in spherical coordinates using tesseroids (spherical prisms) with variable densities in depth. It builds on previous work by the authors and introduces a new density-based discretization algorithm to ensure the accuracy of...
A recent editorial in Nature Methods, “Giving Software its Due”, described challenges related to the development of research software and highlighted, in particular, the challenge of software publication and citation. Here, we call attention to a system that we have developed that enables community-driven software review, publication, and citation:...
An efficient forward modeling algorithm for calculation of gravitational fields in spherical coordinates is developed for 3D large‐scale gravity inversion problems. 3D Gauss‐Legendre quadrature (GLQ) is used to calculate the gravitational fields of mass distributions discretized into tesseroids. Equivalence relations in the kernel matrix of the for...
Estimating the relief of the Moho from gravity data is a computationally intensive non-linear inverse problem. What is more, the modeling must take the Earths curvature into account when the study area is of regional scale or greater. We present a regularized non-linear gravity inversion method that has a low computational footprint and employs a s...
Verde is a Python library for gridding spatial data using different Green's functions. It differs from the radial basis functions in scipy.interpolate by providing an API inspired by scikit-learn. The Verde API should be familiar to scikit-learn users but is tweaked to work with spatial data, which has Cartesian or geographic coordinates and multip...
FREE PDF (open access): http://dx.doi.org/10.1190/tle36020179.1
Links to open source code at http://www.leouieda.com/papers/nmo-tutorial.html
Open any text book about seismic data processing and you will inevitably find a section about the normal moveout (NMO) correction. When applied to a common midpoint (CMP) section, the correction is suppose...
DOWNLOAD PDF AND CODE AT http://www.leouieda.com/papers/paper-moho-inversion-tesseroids-2016.html ---------------------------
Estimating the relief of the Moho from gravity data is a computationally intensive nonlinear inverse problem. What is more, the modelling must take the Earths curvature into account when the study area is of regional scale...
DOWNLOAD PDF + SOURCE CODE: http://www.leouieda.com/papers/paper-tesseroids-2016.html
We present the open-source software Tesseroids, a set of command-line programs to perform the forward modeling of gravitational fields in spherical coordinates. The software is implemented in the C programming language and uses tesseroids (spherical prisms) for t...
PDF available at: http://www.pinga-lab.org/papers/paper-quadrilatero2-2016.html
Airborne gravity gradiometry data have been recently used in mining surveys to map the 3D geometry of ore deposits. This task can be achieved by different gravity-gradient inversion methods, many of which use a voxel-based discretization of the Earth's subsurface. To p...
Fatiando a Terra (Portuguese for Slicing the Earth) is an open-source Python toolkit for modeling and inversion in geophysics. It provides an easy and flexible way to perform and implement geophysical data analysis. Official website and documentation: http://www.fatiando.org DOI for this release: http://dx.doi.org/10.5281/zenodo.49087 Main changes...
Fatiando a Terra (Portuguese for Slicing the Earth) is an open-source Python toolkit for modeling and inversion in geophysics. It provides an easy and flexible way to perform and implement geophysical data analysis.
Official website and documentation: http://www.fatiando.org
Main changes to version 0.5: http://www.fatiando.org/changelog.html#versio...
We have developed a fast total-field anomaly inversion to estimate the magnetization direction of multiple sources with approximately spherical shapes and known centres. Our method is an overdetermined inverse problem that can be applied to interpret multiple sources with different but homogeneous magnetization directions. It requires neither the p...
A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates. Official website and documentation: http://tesseroids.leouieda.com/ This is the first release after the code was ported from Python to C. It was d...
A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates. Official website and documentation: http://tesseroids.leouieda.com/ Changes to version 1.1.1: Minor release for bug fixes: * BUG fix: Wrong result...
A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates. Official website and documentation: http://tesseroids.leouieda.com/ This was the final version of the software that accompanied my bachelor's thes...
A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates. Official website and documentation: http://tesseroids.leouieda.com/ This is the 1.1 release of Tesseroids. See the documentation (http://tesseroid...
A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates. Official website and documentation: http://tesseroids.leouieda.com/ The first ever release of Tesseroids. This initial version was made in Python...
A collection of command-line programs for modeling the gravitational potential, acceleration, and gradient tensor. Tesseroids supports models and computation grids in Cartesian and spherical coordinates. Official website and documentation: http://tesseroids.leouieda.com/ Changes to version 1.2.0: * General improvements to the adaptive discretizatio...
Fatiando a Terra (Portuguese for Slicing the Earth) is an open-source Python toolkit for modeling and inversion in geophysics. It provides an easy and flexible way to perform and implement geophysical data analysis. Official website and documentation: http://www.fatiando.org Changes to version 0.3: * New module fatiando.gravmag.normal_gravity * **B...
Fatiando a Terra (Portuguese for Slicing the Earth) is an open-source Python toolkit for modeling and inversion in geophysics. It provides an easy and flexible way to perform and implement geophysical data analysis. Official website and documentation: http://www.fatiando.org This is the first public release of the package.
We have developed a fast total-field anomaly inversion to estimate the magnetization direction of multiple sources with approximately spherical shape and known centres. Our method can be applied to interpret multiple sources with different magnetization directions. It neither requires the prior computation of any transformation like reduction to th...
DOWNLOAD PDF: http://www.pinga-lab.org/papers/paper-quadrilatero-2014.html
The Quadrilátero Ferrífero in southeastern Brazil hosts one of the largest concentrations of lateritic iron ore deposits in the world. Our study area is over the southern flank of the Gandarela syncline which is one of the regional synclines of the Quadrilátero Ferrífero. T...
We developed a method that drastically reduces the number of the source location estimates in Euler deconvolution to only one per anomaly. We use the analytical estimators of the Euler solutions. Our approach consists in detecting automatically the regions of the anomaly producing consistent estimates of the source horizontal coordinates. These reg...
Presented at EAGE 2014
OPEN-ACCESS ARTICLE.
DOWNLOAD PDF: http://dx.doi.org/10.1190/tle33040448.1
DOWNLOAD SOURCE: http://www.leouieda.com/papers/paper-tle-euler-tutorial-2014.html
In this tutorial, we will talk about a widely used method of interpretation for potential-field data called Euler de-convolution. Our goal is to demonstrate its usefulness and, most importa...
Open licensed (CC-BY) lecture notes in geophysical inverse problems (in Portuguese).
Source code: https://github.com/pinga-lab/inverse-problems
PDF: http://dx.doi.org/10.6084/m9.figshare.1192984
We have provided supplementary material to our article
titled “Estimating the nature and the horizontal and
vertical positions of 3D magnetic sources using Euler
deconvolution” and whose authors are Felipe F. Melo,
Valeria C. F. Barbosa, Leonardo Uieda, Vanderlei C.
Oliveira Jr, and João B. C. Silva. In this material, we
presented an extra sy...
We have developed a new method that drastically reduces the number of the source location estimates in Euler deconvolution to only one per anomaly. Our method employs the analytical estimators of the base level and of the horizontal and vertical source positions in Euler deconvolution as a function of the x- and y-coordinates of the observations. B...
DOWNLOAD PDF + SOURCE CODE: http://www.pinga-lab.org/papers/paper-polynomial-eqlayer-2013.html
We have developed a new cost-effective method for processing large-potential-field data sets via the equivalent-layer technique. In this approach, the equivalent layer is divided into a regular grid of equivalent-source windows. Inside each window, the p...
>>> PDF and talk recording: http://www.leouieda.com/talks/scipy2013.html <<<
Geophysics is the science of using physical observations of the Earth to infer its inner structure. Generally, this is done with a variety of numerical modeling techniques and inverse problems. The development of new algorithms usually involves copy and pasting of code,...
DOWNLOAD PDF + SLIDES: http://www.leouieda.com/talks/seg-carlos2012.html
We have interpreted the airborne gravity gradiometry data from Carajás Mineral Province (CMP), Brazil, by using two different 3D inversion methods. Both inversion methods parameterized the Earth‟s subsurface into prismatic cells and estimate the 3D density-contrast distributi...
DOWNLOAD PDF: http://www.leouieda.com/talks/seg2012.html
We present an improvement to the method of 3D gravity gradient inversion by planting anomalous densities. This method estimates a density-contrast distribution defined on a grid of right-rectangular prisms. Instead of solving large equation systems, the method uses a systematic search algori...
DOWNLOAD PDF + SOURCE CODE: http://www.leouieda.com/papers/paper-planting-anomalous-densities-2012.html
We have developed a new gravity gradient inversion method for estimating a 3D density-contrast distribution defined on a grid of rectangular prisms. Our method consists of an iterative algorithm that does not require the solution of an equation...
We provide supplementary material to Uieda and Barbosa (2012). The material included are: (1) plots of the predicted and synthetic gyy and gyz components from the section "Application to synthetic data", (2) plots of the results of the sensitivity analysis to uncertainties in the density-contrast value of the seeds, (3) the contour maps of the synt...
We present a new gravity gradient inversion method for estimating a 3D density-contrast distribution defined on a grid of prisms. Our method consists of an iterative algorithm that does not require the solution of a large equation system. Instead, the solution grows systematically around user-specified prismatic elements called "seeds". Each seed c...
This paper is in Portuguese.
We have interpreted the airborne gravity gradiometry data from Quadrilátero Ferrífero, an iron ore province in southeastern Brazil. Aiming at retrieving the geometry of the iron body, we have used a fast and novel gravity inversion method for estimating a 3D density-contrast distribution defined on a grid of prisms. Thi...
This paper presents a novel gravity inversion method for estimating a 3D density-contrast distribution defined on a grid of prisms. Our method consists of an iterative algorithm that does not require the solution of a large equation system. Instead, the solution grows systematically around user-specified prismatic elements called “seeds”. Each seed...
DOWNLOAD PDF: http://www.leouieda.com/talks/eage2011.html
We present a new gravity gradient tensor inversion for estimating a 3D density-contrast distribution defined on a user-specified grid of prisms. Our method consists of an iterative algorithm that does not require the solution of large equation system. Instead, the solution grows systematica...
We have interpreted the airborne gravity gradiometry data from Quadrilátero Ferr'ifero, an iron ore province in southeastern Brazil. Aiming at retrieving the geometry of the iron body, we have used a fast and novel gravity inversion method for estimating a 3D density-contrast distribution defined on a grid of prisms. This inversion approach combine...
DOWNLOAD PDF: http://www.leouieda.com/talks/goce2011.html
The new observations of GOCE present a challenge to develop new calculation methods that take into account the sphericity of the Earth. We address this problem by using a discretization with a series of tesseroids. There is no closed formula giving the gravitational fields of the tesseroid...
DOWNLOAD PDF: http://dx.doi.org/10.6084/m9.figshare.963547
DOWNLOAD SOURCE: https://github.com/leouieda/barchelor-thesis
The GOCE satellite mission has the objective of measuring the Earths gravitational field with an unprecedented accuracy through the measurement of the gravity gradient tensor (GGT). The data provided by this mission could be us...
