Query Continents

[SimonTarr]

Hello, I'm hoping someone can help me with what feels like a rather straightforward problem.

I am conducting research into the distribution of body size in Squamates (Snakes and Lizards) in Europe and North America. Before I get into the interesting stuff, I need to simply compile a list of all the species recorded on these continents (as two separate tables- one for each continent). I have downloaded the relevant data from the IUCN website and have opened it within ArcMap with no problems. I can see range data for all the species recorded in the database.

I was wondering how I can select just a continent and export the list of all species present (according to the shapefile). Do I need to draw a polygon around the required area and run a query that way? If so, how can I go about doing this?

Many thanks for your time, I'm really hoping someone can help the n00b!

Simon

[JoshuaChisholm]

Hello Simon,

I'm not sure if this suits your needs, but you can get a summary of any field by opening the attribute table, right-clicking on the desired field (like species) then click 'Summarize...'. The resulting table (with default settings) should be unique by species name with a count of occurrences.

If you only want it for a particular continent, just do a select by attribute ("Continent" = 'North America') then run the summary. It will only use selected records to generate the table.

Let me know if this works out of you.
Good luck!

[SimonTarr]

Hi Josh, many thanks for the speedy reply.

From what I can see, there doesn't appear to be any "raw" location data within the attribute table. By that I mean there is no field that says "North America" or "Europe" or even a state/country. I have checked a few times and, unless I am overlooking something, that kind of data isn't present. There is a field in the attribute table called Shape (Type=Polygon). I'm guessing this is where the range data is located, but it appears as though I can't actually query this.

Thanks,

Simon

Hello Simon,

I'm not sure if this suits your needs, but you can get a summary of any field by opening the attribute table, right-clicking on the desired field (like species) then click 'Summarize...'. The resulting table (with default settings) should be unique by species name with a count of occurrences.

If you only want it for a particular continent, just do a select by attribute ("Continent" = 'North America') then run the summary. It will only use selected records to generate the table.

Let me know if this works out of you.
Good luck!

[JoshuaChisholm]

Select by location!

The exact same process above, but us select by location instead of select by attribute. With select by location, you need to choose the spatial selection method (I would probably use "Intersects" which just finds polygons that overlap at all). You'll also need polygons for the continents. You can find that data online (maybe here). You'll need to play around with it a bit to get the right selection of species data, but this is the general idea:
1) Select you're desired continent(s) (like North America) in the continents feature class.
2) Use select by location to select the polygons with species data (make sure you check the only use selected features box so that it only selects species polygons that overlap with North America).
3) Run the summary on the selected species polygons (see other post).

Good luck!

[SimonTarr]

Thanks so much for your help. I will have a go now and shall report back.

Simon

[SimonTarr]

Just wanted to report back to say this worked perfectly. Thanks very much for your assistance.