Why you need the ArcGIS API for Python in your life...

Why you need the ArcGIS API for Python in your life...

ArcGIS API for Python got a recent new release (v1.2.1), but what is it? ArcGIS API for Python is a web GIS integrator for arcpy and other Python 3 packages and you can think of it as a unifying technology for the ArcGIS Platform.

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Updated imagery you say….

Updated imagery you say….

We have two exciting announcements about World Imagery services. In the next month, we will be receiving a UK wide update to the Imagery and Imagery with Labels basemaps. This is in addition to the new World Imagery (Clarity) service. Read on to find out what’s changed and for more details on the World Imagery (Clarity) service.

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Using Domains and Subtypes for Smart Data Collection

Using Domains and Subtypes for Smart Data Collection

If you’re using Collector for ArcGIS, or thinking about using it, you’ll have considered which fields you need to collect information. You could just use free text and type information into each field. I don’t know about you, but I have clumsy thumbs and there would be spelling mistakes everywhere. If you have access to ArcGIS for Desktop, you should consider using domains and subtypes.

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Vector Tiles Part 1 - Creation

Vector Tiles Part 1 - Creation

Vector tiles contain vector representations of data across a range of scales. Unlike raster tiles, they can adapt to the resolution of their display device and even be restyled for multiple uses. With ArcGIS Pro 1.4 users can now also publish their data as vector tiles using local projections such as British National Grid. In this first of two posts, I'll take you through the steps required to publish your own vector tiles using a local projection.

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Living Atlas of the World Site Update

Living Atlas of the World Site Update

The Living Atlas of the World is the foremost collection of global geographic information and is part of the ArcGIS Platform. You can explore maps and data from Esri and thousands of other organisations, then combine them with your own data to create new maps and applications. The latest update to the website has made browsing this content easier than ever before.

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The Esri UK Open Data site is here and here’s how to set up your own

Have you seen ArcGIS Open Data, which you can set up free from your ArcGIS Online Organization Subscription? This article will give you a broad introduction into what ArcGIS Open Data is, how you can activate it and show you examples of Open Data Portals already available for you to use.
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10 minutes in the Marketplace

In September the ArcGIS Marketplace was launched. I thought I would spend 10 minutes to find out what I can do with it. In this time I was able to secure a free trial for a new reporting app and use open data through ArcGIS online to produce an interesting view on GCSE attainment in the UK.
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Using Yahoo pipes with ArcGIS Online

I recently read a blog post about using Yahoo pipes on ArcGIS online to map out Flickr photos. That was the first time I’d heard about Yahoo pipes. This got me curious about what pipes actually were. So I did a little bit of digging around, and found that they were actually a very useful set of tools. Pipes essentially enable you to ‘mash up’ and create new content dynamically over the web, akin to ArcGIS online, except with any content (including non-geographic). This is not a new concept – speak to any web developer, and they’ll tell you how they’ve been doing this for years. However, the crucial advantage that Yahoo Pipes gives us is the relatively user friendly interface that allows the user to build up these ‘pipes’. I think it’s quite comparable to the model builder interface on ArcGIS desktop, where a user can drag and drop tools to put together a single geoprocessing task.

 

The end products of these pipes are web services, containing simple csv files or KML/RSS feeds. These urls are dynamic, which means the contents are constantly updated. A lot of pipes are not related to any mapping content – they are merely a mash up of various RSS feeds, or an updated listing of TV programs from various websites. However, pipes can also contribute to some really good, dynamic content for ArcGIS online. In this blog post, I’ll take you through how I created a useful pipe for News feeds from the BBC website.

There are a lot of good news feeds served up by the BBC as RSS feeds, and one such feed is the World news one. This feed has all the top headlines from around the world in an RSS feed. One of the drawbacks of having this data as an RSS feed is that we can’t put it on a map. However, we can use Yahoo pipes to do that clever bit of processing to convert it into a GeoRSS feed so that we can use it on ArcGIS online. The first step is to import our feed into the Pipe:

      

 

We use the text input to get the URL as text; We then supply the url to the news feed in the ‘default’ field. This gives us a link to the BBC news feed so that it can be passed into the pipe.

We then need to pass this url through a geocoder that uses the place name in the RSS feed to give it a lat and long. In this example, I use the geonames service, which is a free Global city level geocoder. In order to use that service, I just need to add a bit of text at the beginning of the url – I can use the url builder module to create my url, which then sends the information to geonames and receives a lat and long against each record.

 

 

We can then use the fetch feed module to bring that feed back into Yahoo Pipes, and finally use the output to generate a dynamic link to my brand new GeoRSS feed!

 

On the Yahoo pipes run page, I can see a yahoo map with my geocoded news articles:

 

To use this in ArcGIS online, all we need to do is grab the link from the ‘more options’ menu, and Right click on Get as KML, and copy the link location. If we then switch over to ArcGIS online, we can use the ‘Add layer from Web’ option to add this dynamic KML layer. If you need control of the symbology, then we can add it as a csv file. All we need to do is change the url from ‘=kml’ to ‘=csv’:

 

 

Once we hit add layer, voila! We have a dynamic GeoRSS feed on ArcGIS online (with some nice symbology to boot!):

Once it is on ArcGIS online, we can add other content (either from ArcGIS online or from your own geographic data) to add more intelligence to this webmap. This webmap will only work as long as it can establish a connection to the Yahoo Pipes service.

Related Content:

Help documentation for Yahoo Pipes - http://pipes.yahoo.com/pipes/docs

Tutorials - http://pipes.tigit.co.uk/

FAQ and further information - http://pipes.yahoo.com/pipes/docs?doc=overview

To cache or not to cache

A colleague recently asked us about offering some advice on delivering a fast web service  to a client who was using a combination of ArcGIS for Desktop and the web. The datasets are from the Ordnance Survey’s OpenData offering.

 

 

The datasets included:

1. OS Street View.

2. OS Vector Map District.

3. OS 50k  Raster.

4. OS 250k Raster.

5. OS Miniscale.

 

Their challenge was working out whether to deliver a cached map service to a client, a dynamic map service or a mixture of a cached map service and the original data as a Geodatabase? The issues he needed to deal with included the time it took to create the map caches versus performance versus utility versus cost. A multi-layered issue but ultimately it boiled down to answering the question ‘to cache or not to cache?’

Actually, his question was answered initially by another question, why bother? Consider signing up with Esri UK’s free cloud-enabled map services and become productive immediately. Leave the caching work to us. This is a route that a lot of organisations are already doing and Esri UK has been happily serving up fast, visually pleasing map services since the service went live in late 2011. However, the client in question was ‘air-gapped’ and could not connect to the internet for security reasons.

So back to the original question. Our recommendation is that it’s often best to cache your data rather than serve it out dynamically.

Server Performance

The resultant CPU and RAM for serving a cached map is tiny compared to the very CPU and RAM intensive operations of rendering the same image dynamically. Most applications will be unable to scale up to heavier use if the base map is not cached.

A map service that is cached can therefore scale very easily as more and more users are added.  Esri UK’s cloud-enabled map services are happily serving a vast number of map views a month and a high level of concurrent users with little effort.

A dynamic service would be unable to get close to the performance of a cached map service as users increase. Parity between dynamic and cached map services exists only at very low levels of usage, say one user. Also, LocalView Fusion[1] templates are designed for cached base maps and some functionality is limited when a dynamic base map is used.

Architecture

There are also architectural differences when using a cached map service:

 o   A web browser can cache tiles it has requested previously, thus reducing the number of hits each client makes on the services over time. Similarly, most users may have some sort of cache or proxy server that also performs the same task but at the network level.

 o   Web servers are designed and optimised for serving lots of files off disk and/or memory; it is how web apps should work.

 o   By comparison dynamic images usually involve a number of resource intensive tasks including: data search, results retrieval, image generation, disk I/O to save the image to disk (even when streaming as MIME[2]) and other such steps.

Other Considerations

Of course, a cached map service isn’t a magic bullet to all of one’s requirements. There are a number of issues to think about: 

  1. Time: One needs to spend time (in some cases, a lot of time) to produce the map cache. The process is dependent on many factors: the number of scales, image type and resolution to pick out three. With the need to potential roll out updates quickly, cached map services may not be the most agile option.[3]
  2. Size on disk: Disk space usage will be a concern as a map cache can take up a significant amount of space. The Esri UK map services currently have a disk foot-print of 3 terabytes (and growing) – all this has a cost in storing and managing.  
  3. Caching Processes: Resources required for creating cache – multi-servers may be required to reduce time but it increases cost. Faster servers may need to be provisioned.
  4. Update Frequency: If the data changes a lot, then it potentially means there is a need to re-cache the data; either all of it the changed portions. Workflows need to be developed to enable this introducing an overhead.
  5. Less Dynamic: If a client needs to perform client side processing such as online digitising, dynamic rendering of layers or some other function; a map cache may not be suitable.
  6. Scale limits: The largest available scale of a map cache may not contain enough detail for certain workflows and organisations.

So in some cases a more subtle and nuanced workflow may be needed such as combining the advantage of both dynamic and cached map services. For example, a client may require data to be available down to 1:500, 1:250 or 1:100 which is just not practical to build map caches using current prices and resources.  So a viable solution would be to use vector data from a File Geodatabase as a base map for these scales, then utilising cached raster maps as the base map once you’ve zoomed out far enough.

For those interested you can see the cache levels and hardware specifications we typically use for building national caches here.

 


[1] Esri UK’s Platform-as-a-service offering

[2] http://en.wikipedia.org/wiki/MIME

[3] Though many options and alternative workflows exist to maintain a continuously changing map cache; we will explore some of these options in future blog posts.

[4] http://aws.amazon.com/ec2/instance-types/

Tip: Set your region in ArcGIS.com for UK featured content

Earlier this month it was announced that there had been some updates to ArcGIS Online. I wanted to highlight one of these enhancements in particular which I believe will be of interest to UK based users.

It is now possible to localise ArcGIS Online for the UK. Defining your region sets the featured maps on the home page, content in the gallery, and the default extent of new maps in the ArcGIS.com map viewer to UK specific content.

The carousel on the ArcGIS.com home page will be populated with UK specific content as shown in the image below. Also, if you navigate to the Gallery then you’ll see that this also now contains UK Maps, Web and Mobile Apps.

Before seeing these changes you will need to modify your region in your ArcGIS.com profile. To do this follow these steps

  • Ensure that you’re logged into ArcGIS.com
  • Click on your name in the top banner to access your profile
  • In the Region options select “United Kingdom” (see below)
  • Click the Save button

Whilst you’re on your profile page, why not ensure that you’ve included some information about yourself and perhaps upload a photo of yourself?

The other major benefit to setting your region is that all new webmaps that you create with the ArcGIS.com map viewer or ArcGIS Explorer Online will initialise with the extent of the UK. This means that you wont have to zoom and pan to the region before starting to create your map.

The maps and other content that appear in the UK Featured Maps and the Gallery will continue to be refreshed so keep an eye out for new content. Also, if you’ve created a map that you wish to be included in these sections then please let us know. 

Creating a web map from UK Open Data

There's never been a better time to make web maps! Source data is available for free online (see this blog post on Open Data), the software to visualise this data is cheaper and more powerful than ever, and the Internet is a convenient way to share the maps you create.

I'm going to talk about my own experience of creating a web map from Open Data published by the Driving Standards Agency (DSA) in the UK. The DSA administers all the practical driving tests in Great Britain (but not Northern Ireland) and publishes statistics about how many people pass at each test centre. The national average for the practical car driving test was 46% in the year 1 April 2010 to 31 March 2011, but this number hides a lot of variation among the different test centres across the country. Dense urban areas tend to have much lower pass rates than more sparsely populated rural regions: the average is as low as 30% in parts of London and West Yorkshire, and as high as 80% in the remote Scottish islands. This is the kind of data that would look great on a map, and I decided to make one when I couldn't find anything like it already.

Above: Average car driving test pass rates across Great Britain. Cities such as Birmingham, Glasgow, Leeds and London (dark red) have the highest failure rates. Dark blue areas have the highest pass rates. This map should not be interpreted as a map of "easy" places to take your test; if you're badly prepared then you'll fail, no matter where you take it! Click here for the full map.


First, the legal niceties. In 2010, the UK government created a generic data licence called the Open Government Licence (OGL); anyone in the world is allowed to reuse data released under the OGL (e.g. make maps from it) without charge, as long as the original creator of the data is acknowledged. Many UK public sector bodies, such as the Department for Transport (of which the DSA is a part), release much of their data under the OGL. If in doubt, you should email the agency who produced the data you are interested in to get clarification. It's always worth doing this because it's incredibly frustrating to spend time producing a beautiful web map, only to realise you can't actually publish it because you've breached copyright!

The data source I started off with was this PDF file, which has statistics broken down by calendar month, driving test location and gender. Although this is fine for looking up details of your local test centre, it's very difficult to compare different centres using a long list of tables.

The first challenge was to get the location of each driving test centre as a pair of (X, Y) coordinates, i.e. geocode the test centre names. The Department for Transport (DfT) publishes a full list of test centres with addresses on their website; this data can be extracted, or scraped, from the web page using a custom script. I also found an online resource called ScraperWiki, where programmers and citizens with ideas can get together and collaborate to produce scraping software for difficult data sources. This particular screen-scraping script (try saying that quickly three times) was designed to pull out a list of driving test centres from the DfT website, so I had a usable list of test centre locations to work with, without having to write my own scraper.

The next step was to write a Python script to take the data in the PDF file, look up the postcode of each test centre in the scraped data, then use the free Code-Point Open dataset to convert the postcode into an easting/northing coordinate. The output was a CSV file with a row for each test centre containing its location and associated pass rate statistics. This wasn't straightforward for two reasons: firstly, the names of the test centres are sometimes slightly different in the PDF compared to the scraped data (e.g. "Island of Mull" vs. "Isle of Mull"), so the Python code had to do a bit of guessing; secondly, some of the postcodes on the DfT website are invalid! In this case, I had to manually correct them.

Once I had the locations and statistics for each test centre, it was easy to import them into ArcGIS Desktop. I used the Create Thiessen Polygons tool to generate a catchment area polygon around each point, then clipped my polygons using Ordnance Survey's free Boundary-Line dataset. Thiessen polygons mark out areas around each test centre containing locations closer to that test centre than any other test centre (in a straight-line sense). This assumes that people will travel in a straight line to their nearest test centre: not altogether realistic, but a straightforward piece of analysis that produces simple geometries.

Uploading my map to ArcGIS Online was also easy. The red-blue colour scheme was chosen to be friendly to certain users with Colour Vision Deficiency, a topic that my colleague Will White touched upon in a recent blog post.

Two final notes: first, if the idea of Python scripting makes you want to run away, don't worry because it's a gentle language to learn! The reality is that it's still a frustrating experience working with most Open Data without scripting experience, although if you are an experienced spreadsheet user then you may be able to get around this. There are inevitably times when you will need to automate part of your workflow, so even a modest knowledge of Python (the scripting language of choice in GIS these days) can go a long way. This page links to several useful resources for Python beginners and Esri UK also runs introductory Python training courses delivered over the Internet.

Second, in my experience, at least 70% of your time building a web map will be spent collecting and processing data rather than designing a map. Of course, this doesn't mean that the aesthetic elements of a web map aren't important, and the balance of work can certainly tilt more towards design if your map has a complex layout and symbology. Still, it's important not to underestimate the amount of time that data preparation takes. On the bright side, once you're done massaging raw data into something usable, most of the pain is over. Have fun mapping!

Creating office location maps on ArcGIS.com - Part 2

In part 1 of this series we demonstrated the processes for preparing your data for use in ArcGIS.com.  Now we will start creating content on ArcGIS.com to share with colleagues and the wider world. As part of this section we will upload all of the datasets that we have created earlier (below) for sharing within our organisation.

My Content on ArcGIS.com

View all the content on ArcGIS.com

Map and layer package sharing

Open Map Package from ArcGIS.com

First we will have a look at the sharing of map and layer packages with others.  This is as simple as uploading your packages to ArcGIS.com, filling in the appropriate tags, descriptions, usage constraints and sharing the content with the appropriate groups.  Map and layer packages can be either uploaded directly in ArcMap using the upload selection when you create the package or they can be uploaded via the Add Item tool in the 'My Content' section of ArcGIS.com.  Take a look at the best practice advice for sharing content on ArcGIS.com.  Once you have shared the items via ArcGIS.com you or anyone who can see your content can then open it directly in ArcMap using the file open drop down (right).

View the map and layer packages on ArcGIS.com

Creating web maps with Shapefiles

Now we are going to create a map using the compressed shapefile we created in part 1.

  1. Create a new map by navigating to http://explorer.arcgis.com.
    If you are not presented with a map, click the New Map button at the top left to start a new web map.
  2. Add the appropriate basemap layer.
    Again, I will choose OpenStreetMap as it is my basemap of choice.
  3. ArcGIS Explorer Online: Add ContentClick the Add Content button button and choose to Import data from a Shapefile.
  4. Follow the dialog instructions to upload your shapefile zip folder into the map.
  5. As this is a small data point data layer I will choose to not generalise my data when importing, so choose to 'Keep original features' when importing and continue.
  6. To configure the symbology you will need to click on the 'Layers' tab (1) on the left-hand panel.  If, like my map, you have to change the name of your layer to remove unsightly underscores, click on the 'Organise' button at the bottom and edit the name of the layer.  If there is a layer called 'Map Notes' that has already been added to the table of contents, remove it using 'Organise' also. 
  7. To symbolise the layer, drill down into the layer properties (2). 
  8. On the next screen, select Display -> Configure and then choose a symbol that is appropriate for you.
    You can use your company logo icon if it is hosted on a web server somewhere, you can do this by choosing the custom symbol type and linking to the location of your logo icon.
  9. To configure the popup, select Pop-ups -> Configure.
  10. First we will add the office image to our popup.  Navigate to the 'Media' tab and then select 'Add'.  Remove the default title 'Image', we won't display this.  Add the Image URL to the URL field by using the blue Add buttons on the right of the field.  Then do the same for the web address which will act as a link when the user clicks on the image.
  11. Then we need to configure the text content of the popup.  Navigate back to the Title and Description tab and then select the 'Custom' option from the description radio buttons.  Now we can add free text into the description.  Here you can also use the blue Add button to add data attributes as text to the popup.  We add the Name, Address, Phone and Fax fields on separate lines.  For the Name field, we have chosen to make it a hyperlink back to the Url that we defined in our original data.  To do this, select the '{Name}' text and then click on the 'Insert Hyperlink' button and add a hyperlink using the {Url} field as the link location.

Now that we have finished creating our map with the shapefile data we can save it, fill in the metadata and add full public access to this map so that we can consume it in our website as an embeddable map.

View the shapefile web map on ArcGIS.com

Creating web maps with CSV files

Creating web maps with CSV files is much the same process as that used for the above shapefile workflow.  The only difference is that the importing of data is slightly different.  We'll jump in at step 4 of the shapefile process:

  1. This time select CSV as the import format.
  2. Choose to browse for your file on disk and then follow the dialog to locate it.
  3. The data will be displayed in the text area to show you that the file content have been accessed, then click Next.
  4. The import tool will automatically select the 'Address' field as the Location field (this means that it will use the address field to geolocate the data).  As we have already added coordinates to our data in the Point_X and Point_Y fields we will want to disable this by setting the data type of the Address field to Text.  The second part of this process will be to register the X & Y fields as the spatial fields.  
  5. To reference the Point_X and Point_Y fields as the locations fields we simply need to set the data type to Location, then in the subsequent Location Type drop down, choose the coordinate type (Longitude for Point_X and Latitude for Point_Y).
  6. Click Import and the data will be added to the map.

The CSV data we added also has the latitude and longitude fields which we can now add to the info window text.  We do that much the same way as we did with the other text attributes (below).

Now that we have finished creating our map with the CSV data we can save it, fill in the metadata and add full public access to this map so that we can consume it in our website as an embeddable map.

View the CSV web map on ArcGIS.com

Creating web maps with KML files

Creating maps using KML files is a slightly different process, here we can access the KML files that we have uploaded to ArcGIS.com.  When adding KML files all we need to do is add the KML layer from 'My Content' to the map.  The symbology of the data is defined in the KML layer configuration therefore we cannot change the look & feel of the layer in ArcGIS.com.

View the KML web map on ArcGIS.com

OpenStreetMap Attribution

The OpenStreetMap (OSM) basemap layer does display the OSM attribution which is required by the licence, but I also add links to the project and the license in the Access and Use Constraints and the Credits fields of the web map in the form specified by the project.

Web Maps

I have made all of the above web maps fully publicly accessible to allow us to embed the web maps in our company website.  You can do this using the 'Share' button when you are in the map and then selecting 'Embed in Website', that will give you the code that you need to drop into your website.  The embeddable map is created using the ArcGIS API for JavaScript Compact Build, which, in short is a smartphone accessible web map meaning that people viewing your website on a smartphone (who may well be looking for your office) are able to view and navigate the map.

View all three web maps on ArcGIS.com

Conclusion

We've seen how to create and upload our office locations data to ArcGIS.com in various formats.  We've also seen how we can consume that content on ArcGIS.com to create maps which we can embed in our website or share with others.  ArcGIS.com is an evolving platform and new features are being added on a regular basis.  Watch this space for new feature announcements.

View all items on ArcGIS.com

Cloud computing at Esri UK

ISG (Internet Services Group) has for the last six years been managing Esri UK's hosting and web services both for internal and external clients. This was supported through internal and third party hosting suppliers.

The cloud offered a number of differences (I would not use the term 'advantages') over traditional on-premise hosting.

The on-going debate between on-premise and cloud solutions comes down to specific details and requirements within each organisation. The decision to go with one or the other solution should be made only after reviewing each organisation’s unique situation. Cloud computing offers a lot but it should not be regarded as the magic bullet.

ISG started off with an on-premise model but over time migrated towards a cloud-computing infrastructure as provided by Amazon Web Services (AWS) and taking advantage of the utility pricing model where one only pays for what one uses. When a server or resource is not required, it is turned off saving money both in terms of management and power. There is no need to pay for excessive capacity.

AWS had been working with Esri Inc to create ArcGIS Server Amazon Machines Images (AMI) - which are pre-created ArcGIS Server 10.0 virtual machines running on the AWS cloud. ISG have been using these AMIs, editing and reconfiguring them for our specific requirements and commissioning them for use. For ISG, the cloud has meant that managing hardware and software with a small team, isn't such a time consuming task anymore. Gone are the days where one needs to travel down to our hosting centre to change disks. The headache of hardware upgrades are now a thing of the past as AWS continues to add and maintain the underlying hardware. 

For Esri UK the PROS and CONS of a Cloud model of service provisioning include:

PROS:

•Lower Total Cost of Ownership (TCO) - certainly, the cost to the business of setting up a hosted service has dropped dramatically. In the past, even before the first user - a hosted solution would have cost upwards of £1,000s to setup. Now, a few days of work and the service is usually ready.
•Scalable performance to fit business’s needs. If a service has seasonal peaks (i.e. an online conveyancing service or a charity web site) then the ability for the resources to expand in terms of size and power as usage demands it becomes a big plus for us. Resources can be added almost instantly. In the past, one had to purchase extra hardware which would become redundant after the initial peak requirement. The cloud grows as big and as quickly as demand requires or conversely, can shrink down to a minimum. Saving in cost all round.
•Reduce upfront costs on hardware and software means that ISG does not need to spend days working up estimates on hardware costs and maintenance payments.
•Higher server availability and recovery. If one server fails, it is automatically picked up on another server assuming a copy of it was made. Usually, this new server can be online within minutes. Even higher availability can be provided if the solution involves clustering and load balancing.
•Utility based. With a cloud solution we will only pay for the amount of server resource we need and pay for them on a monthly basis, like electricity.

Hosted CONS:
•Bandwidth costs could potentially be very high if user numbers prove incorrect from estimates.
•Not all software programs can be moved into the cloud.
•Depending on the size of the client, it may not be a great price difference between cloud and on-premise.
•Security can be a concern. If a service or a client has specific security requirements, it may not be able to move to a cloud-based solution.
•Downtime. One is completely dependent on the Internet and service provider. If the Internet is down, service could be offline. The risk is of failure is there but it is borne by Amazon Web Services[i] rather than ourselves.
•Continuous cost, after the initial pain of capital expenditure - the cost of running an on-premise recedes to a background cost of staff salary and core infrastructure costs (power and light); it becomes an asset that depreciates in value. With the cloud, one can have a variable and continuous cost that may be difficult to predict. This can cause issues with budget forecasts and estimates for the business.
•Even for simple demonstrations, testing etc - one still has to pay. One doesn't have an 'old' machine handy to load up a test environment.

Since there are several PROS and CONS to hosted models and on-premise models, ISG has found a compromise in a hybrid solution.  A hybrid solution for ISG means that some of our resources are still on-premise (a combination of physical, virtual and internal cloud resources) these are used for testing, demonstrations and for specific clients. Our production/live services are now cloud-based giving us the best of both worlds.

A lot of other areas need to be discussed such as the relevant performance of disk I/O between  cloud resources as opposed to a physical on-premise resource. Security is another large area of concern as well as the necessary changes in one's working habits.

I guess that's for another time.

 


[i] http://www.zdnet.com/blog/foremski/the-irony-of-a-cloud-knocking-out-amazons-ec2-cloud-services/545

Drawing a GPS track on a web map

A few weeks ago I took a driving test near our head office in Aylesbury. Thinking it might look interesting on a map, and being the ever dutiful GIS geek, I decided to create a GPS track of the route. You can see the result on ArcGIS.com.

View the map

 


Most GPS loggers can create a reasonably accurate trace of a driving route if the GPS device's position is recorded often enough. I logged my location once every 3 seconds on a GPS-enabled mobile phone, which was a compromise between having a high level of detail and having too many points to display on a web map.

Some of the highlights from the test:

A bay parking manoeuvre at the Driving Test Centre at the beginning of the test. No, I didn't go into the hedge. The GPS lies, I tell you!

This is not the proper way to do a roundabout:

(Actually the aerial imagery is slightly out of date: the roundabout above has been replaced by a crossroads)

If you have your own GPS data (in GPX format) then ArcGIS.com makes it easier than ever to draw it on a map. No programming required! Simply create a new map, select the "Add" dropdown menu in the top left and "Add Layer from File".

After you've finished building your maps, don't forget to share them with other users. Have fun!