INTEGRATING GEOCHEMICAL DATA AND RASTER IMAGES TO PRODUCE HIGHLY DETAILED SAMPLE MAPS IN A GIS ENVIRONMENT

One of the great ongoing questions for petrologists in the digital age is how to effectively integrate different sample datasets, which have been collected from the same thin section or mount, into a single cohesive sample map. Three major challenges to the construction of sample maps exist: 1) It is common to collect different types of data, such as digital images (raster data) and excel tables of spot analyses (vector data), that are not easily processed by the same piece of software. 2) Commonly used figure and map generation tools, such as Illustrator, are not optimized for problems such as those that geochemists and petrologists work on, and it is time-intensive to update these maps and figures with new data. 3) Sharing datasets between researchers and research groups is limited by the cost and accessibility of software built to handle such datasets.

A solution to all three problems can be found with the QGIS software package, which is stable, cross-platform, and freely available to all. QGIS was originally built for the purpose of creating maps at the scale of continents and cities, but its tools can be applied just as effectively and efficiently to mapping at the micrometer scale. Moreover, QGIS was built to use the common shapefile and geotiff formats, and supports the development and integration of user-built Python plugins. With the release of QGIS v3.10, the authors have updated an online tutorial built to quickly teach users new to QGIS how this software might be used to expedite many sample mapping tasks. This talk will feature real-world sample maps containing chemically zoned minerals and fracture-fill cements, and will demonstrate how the software streamlines several common microanalytical tasks: importing table data and imagery, changing data display properties, creating line transects, automating creation of figures and appendices, and sharing spatially referenced data with other researchers.

Designed to simultaneously display both imagery and vectorized tables, and optimized for fast and efficient figure generation, QGIS is a no-cost solution to the problem of integrating datasets into highly detailed sample maps.