This is a very simple step by step guide created by a beginner using QGIS for a beginner using QGIS. It will help you to plot a species distribution exported from the Specify database into an Excel file onto a simple map of New Zealand with some bathymetry lines.
First you will need to find a vector layer for your map.
A useful NZ and outlying islands inside the EEZ outline can be found here:
You will need to register to download the data layers but it is free and very quick to do.
Open QGIS new project and set your default Coordinate Reference System for this project
Click on Project in top menu bar
Click on Project Properties
Search for WGS 84 / Mercator 41 EPSG:3994
Enable ‘on the fly’ CRS by ensuring the box is checked.
3. Add a new vector layer
This plots the outline of New Zealand and the outlying islands:
4. Now to add some bathymetry to our map:
You can download bathymetry layers from the NIWA website:
A useful one for a background map is the New Zealand region 250m gridded bathymetric data set and imagery, CANZ (2008). You can download this as an ESRI shapefile (.shp)
For a wider and more colourful bathymetry the Southwest Pacific Region bathymetry is great and you can download that as a GeoTIFF.
5. Now to plot simple data onto the map:
Open your excel file and delete out any fields that contain commas (i.e. a comments field).
Save Excel file as .csv (comma delimited text file)
In your QGIS project make sure your coastline and bathymetry layers are plotted ok
Click on Layer>Add Layer> Add delimited text layer
Now your points should plot onto the map nicely:
This example is all records of Ophiuroidea species in the NIWA Invertebrate Collection Specify database
So what if we want to only plot a subset of the data?
6. As an example I want to only show records of a single species, Ophionereis fasciata
The data plotted is now only the species Ophionereis fasciata:
I also changed the colour of the islands to green and the points to red:
7. This is rather a lot of bathymetry so to plot only a few bathymetry lines on the map, for example 50 m, 100 m and 500 m:
Zooming into the map near Wellington looks like this:
And my final map with just a single species, just a few bathymetry lines, and some nicer colours for the land and data points looks like this: