Cartography Links

Monday, October 31, 2016 at 13:30:12

This week a selection (well list!) of two relatively recent resources which struck a chord.

1. cartographic-design: this is hosted over at Github and is a series of links to cartography sources that supported Maptime Boston’s May 2016 meetup. Its a relatively short but extremely useful set of resources for this wanting slightly more detail on a range of carto/design topics. One to refer back to - often.

2. Beyond the Core Knowledge: a blog post from Gretchen Peterson that looks at some important topics that sit outside (for example) The GIS&T Body of Knowledge. It’s interesting because it takes a concept, a dataset and the hoops to jump through to get (more or less) through to the end. And it’s nice because she covers all those inner decisions you end up making as a designer to get to the final product.

Data transfer and memory cards

Monday, October 17, 2016 at 09:35:24

James and I were in Norfolk a few weekends back completing data collection for his PhD studies (his blog has at least one post relating to this) and the whole topic of data transfer speeds came back to haunt me. Amongst a number of cameras, we had been shooting with the Nikon D700 using a Sandisk 16Gb Ultra card which has read speeds of 30MB/s. We actually filled the card on day 1 (1000 shots) and need to unload the data off it. I had brought with me my cheap and cheerful Integral CF->USB card reader which works fine. Except it took the best part of 30 minutes to copy the data off the card around <5MB/s. Painfully slow.

When we got back I thought I’d dig back into data transfer speeds again. Remember that the firmware (and hardware) in a digital camera will be able to use cards up to a certain specification. The D700 is at least 64Gb cards up to 90MBs (although it might not be able to utilise the full speed of the card). My Fuji XM1 can take 32Gb cards at 50MBs. Now to achieve these speeds during data transfer to a PC, all parts of the chain need to be quick - card, card reader, USB port, bus and hard disk. In this instance the card reader was the limiting factor as it was plugged into a USB3 port on a new laptop. And just as a reminder, USB3 has a throughout of (depending upon what you read), somewhere above 400MBs (and doubling for USB3.1), whilst USB2 somewhere around 35MBs.

So, one lowcost USB3 card reader later and a new (lowcost!) 50MBs SD card, plugged directly into the USB3 port and read speeds race along. Getting this kind of throughout is both cheap and easy, but its not hard to accidentally put a weak link in that chain and see those rates plummet.

FREE EPRINT: Selecting cameras for UAV surveys, GIM International

Thursday, October 13, 2016 at 12:12:00

James O’Connor and Mike J. Smith (2016)
GIM International

With the boom in the use of consumer-grade cameras on unmanned aerial vehicles (UAVs) for surveying and photogrammetric applications, this article seeks to review a range of different cameras and their critical attributes. Firstly, it establishes the most important considerations when selecting a camera for surveying. Secondly, the authors make a number of recommendations at various price points.


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Lies, damned lies and Sainsbury double-speak

Monday, October 3, 2016 at 12:33:14

So a nice piece of environmental marketing below from Sainsburys, but it does frustrate me as a scientist when you see qualifying statements that introduce uncertainty. OK, so, the original statement:

We Harvest Rain
That’s a good statement - up front, some environmental credentials. A positive message

By saving water…
Saving? I assume they mean harvesting, but at least they are trying to use a different word. Collecting maybe??

…we halve the amount of mains water we use…
two qualifications here. Half the mains water. OK, so we dont know if they used anything other than mains water and of course we don’t know the base. What are they comparing this to? Last year? Ten years ago? And just for this store? All Sainsbury stores? All Sainsbury owned/operated buildings, including warehouses and offices?

… per sq ft…
COME ON PEOPLE!! Sainsburys, you moved to grams and litres, as much as some of your customers didn’t like it. WE ARE METRIC!!

…of sales area
Ermmm…. another qualification. I’m guessing, if this is across ALL Sainsbury facilities, then warehouses will make up the vast amount of the floor area. Taking into account what the base is actually measuring against, how does this change from half.

Sorry Sainsbury, BIG fail on the marketing front. Be honest - because every little helps.

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