Spatial Joins and Heat maps
Session 1 in the course Advanced ArcGIS- A computer with Microsoft Windows installed.
- ArcGIS version 10.3.x.
- Most Bangor University computers have this installed.
- If you are a Bangor University student, you can download a copy for your own machine from IT services.
- This session should take about 30 minutes.
- Follow instructions first, and try to achieve the end product you want. If you can’t get something to work that way, try doing it in a different way. Randomly trying things using similar tools or approaches might yield your end product, but if it doesn’t…
- Search online using particular search terms around the area you want, this might yield some tips that you can follow to achieve your end product. Great tools to use are Google, stackoverflow and particular forums relating to the software or process you’re using. Still stuck?
- Go back to 2 and try again, but this time use different search terms, i.e. more specific or vague, but keep the software you’re using in the search to try to locate a solution. If that fails, then drop the software search term and try to find a workflow from a similar program.
- Final resort, throw your hands up and either write a forum post or contact an expert to help.
You might ask why I have written the above, well, it’s for several reasons but foremost is the value that you gain from finding your own answer is that over time you will be able to use very specific searches to find workflows or solutions that directly help you achieve your end product, and you will hardly ever require anyone else’s direct assistance. This speeds up your work, and increases your self reliance.
Other lessons…
Spatial Joins and Heat maps – Session 1 in the Advanced ArcGIS series
In this session, we want to present the distribution of MPAs and some cold-water coral species within the Rockall Bank area of the North East Atlantic. We are particularly interested in producing a strong visualisation that can capture the distribution and show how frequent the corals are, and to achieve this, we will use a “heat map” style approach within ArcGIS to produce an output that is similar to the image below.
The map above shows the distribution of MPAs (also includes potential MPAs yet to be officially designated, as well as other areas of interest), with a heat map style grid, that ranges from light green to dark blue depending on the number of coral records found within a roughly 1km area. The base map is 2km resolution bathymetric data using a stretched colour scale. So, let’s do it!
I recommend you first follow the intermediate worksheet below in your own time, when you get stuck use the video to the right to solve those issues (make sure you are watching in HD mode for best experience):
Video chapters
Step 1 – Download the data
Step 2 – Plot the species locations
Step 3 – Add MPA and Bathymetry data to the map
Step 4 – Prepare for a Spatial Join Operation
Step 5 – Create your Fishnet
Step 6 – Complete the Spatial Join
Step 7 – Use Symbology to colour your Heat map
Step 8 – Clean up, and use Layout to create a print map
Data to download
Bathymetry – http://www.marine-geo.org/tools/GMRTMapTool/
From the GMRT mapper site, you need to select a relatively small area of interest.
MPA distribution – http://www.mpatlas.org/data/
Download the ESRI Geodatabase (.gbd) file from the webpage.
Species distribution – http://iobis.org/mapper/
Locate the species Lophelia pertusa within the system and download individual points observation for this species.