1. Overview

A decade ago it was very difficult to do basic scientific computation or even paper preparation without commercial software. Not only did this put up barriers to those at large universities that could afford commercial liscences, it also meant that a large fraction of science was done using commercial, closed source software. If you didn’t have the liscence, you could not reproduce the analysis.

This is no longer the case. Most of the the commercial tools commonly used by scientists have an open source alternative. In some cases (in our opinion) the open source alternative is better than the commercial alternative.

In this document we will list the tools that we use in my group at the University of Edinburgh. The list is by no means exhaustive and we encourage readers to explore alternative lists (for example [XXXX]).

2. Using a GIS to look at LSDTopoTools data

LSDTopoTools outputs both raster and vector data. If you don’t know what those are please see our section on geospatial data.

2.1. Raster data

Our raster datasets are in the ENVI bil format. We like this format because it is simplebut contains all the georeferencing information you need to load it into a GIS.

  • The ENVI bil format can be read by both ArcMap and QGIS.

  • You can convert it to other formats using GDAL. Note that QGIS has GDAL built in.

2.2. Vector data

LSDTopoTools also produces vector data. This vector data is almost always point data. Points with locations and attributes are printed to file, and you need to get this into your GIS. LSDTopoTools outputs point data in two formats:

  • csv format: This is comma seperated value.

    • Most of our csv data files include the latitude and longitude of the points.

    • If you import csv data into a GIS, you need to tell it the coordinate system. If the csv file has latitude and longitude headers, the coordinate system is WGS-84

  • Geojson format. Some of our LSDTopoTools programs allow you to convert csv files into geojson files.

    • Geojson files contain georeferencing, so you can load them as victor data directly into a GIS: you don’t need to tell the GIS what coordinate system the data is in.

    • Geojson data is also compatble with many web mapping formats, like d3.js

    • Unfortunately, Geojson files are huge so if you are processing big datasets and are writing geojson data you will vey quickly end up filling your hard disk!