Next Melbourne Developer Meetup Scheduled!

Esri Australia are pleased to announce our third Dev Meet up here in Melbourne, on the 23/05/2013.

We have talks lined up covering Twitter Maps, Esri’s new ‘Web Map’ Standard, Geo-fences and ArcGIS Mobile.

If you have something to share, then please sign-up for a 10-minute Lightning Talk.

For more information and to join the group go to:

http://www.meetup.com/ESRI-Australia-Dev-Meetup-Melbourne/

John H

Languages of Melbourne detected from Twitter

Inspired by the great maps from CASA showing the distribution of twitter languages for London and New York, I decided to take on a self development project to try and do the same for Melbourne and in the process learn some more about python, SQL and web development.

At the time of writing, the application shows geolocated tweets that have been collected from November 2012 to March 2013 around Melbourne.   The application allows you to switch between a map of languages (Top 5 languages) and a map of profanity.  Tweets are still being collected and the map caches will continue to be updated with new data every fortnight or so.

There are already some interesting stories in the map such as people tweeting from the airport runways; the lack of Greek being spoken on Twitter despite it being the 2nd most spoken language at home (Census 2011); big mix of languages at universities, the airport and in parks; people tweet a lot on trams & trains; the lack of Chinese languages; tweeters out at sea (only recording confident location matches); and a number of residential houses that like to swear a lot.

A total of 58 languages have been detected so far (map only shows the top 5 that have the most tweets against them).  For now, Malay is leading in the top 5 Languages spoken on Twitter (disregarding English) and the outer eastern suburbs are marginally winning in which suburb swears the most.

Feel free to use the comments section to ask any questions or make any observations/hypotheses of patterns within the data.  It will be interesting to see the data evolve over the next few months to see if the patterns change at all.  If anyone is interested to know more about my learning experiences with this project, I intend on doing a quick talk about it at the next Esri Australia developer meetup in Melbourne.  I will put my slides up as a separate blog post when that happens.

Click to open an interactive map.

 

With webmaps getting all the limelilght these days, I thought I would put together a static map. Click for a HQ version.

Handling Raster backgrounds and NoData

Sometimes there are homogeneous areas in a raster dataset that you do not want to display. These can include borders, backgrounds, or other data considered to not have valid values. Sometimes these are expressed as NoData values, although at other times they may have real values.

Backgrounds and outlines can often be the result of georeferencing your raster dataset. If your raster data has a background, border, or other NoData values, you can choose not to display them or choose to display them as a particular color.

All renderers allow you to set the NoData value to a color or No Color, while the Stretched renderer allows you to identify a specific background value and display color or No Color.

What do you do if you’re still seeing a background colour after applying a 255,255,255 RGB background and the NoData options as in the example below?

If you had other values other than 255, 255, 255 for colours close to white (like 250 for example) and the NoData and Background colour settings were not enough to handle them, then it’s likely that that they may otherwise be rendering errors coming from the image preprocessing, perhaps from compressing the images.

Trying to apply the Spatial Analyst > Reclass > Reclassify tool try to handle that problematic range would only result in you losing the detail in your image by simplifying the spectrum into a new classification.

A better solution is a workflow that should make your data management more efficient as a consequence.

You will need to create a Mosaic Dataset to manage your images and be able to specify the reclassification this way.
The mosaic dataset simply acts as a reference to your images to spatially index them with pyramids for processing and any queries or conditions (like the reclassification of RGB values > 250 for example) you may want to add to them during display.

How To: Create an ArcSDE Spatial View

Spatial views are database views that contain a single spatial column. They are useful in organising your spatial data with other attribute data in a predefined way, in the same database or another database. They are also READ-ONLY, hence spatial views can not be edited via ArcMap. If you are currently still at ArcSDE 10.0 and prior versions, the trick to get this working is to follow these steps:

This blog addresses how to create a spatial view using SQL Server.

A few words about deploying ArcPad onto a Mobile Device that cannot be connected and synchronized with your Desktop machine.

As an ArcGIS Desktop support analyst at Esri Australia, I get a lot questions about deploying software, including questions about ArcGIS Desktop, ArcPad and ArcGIS mobile. From time to time I receive some interesting questions from our clients and some of them are worth to be mentioned in this blog.

One of the most interesting questions that I received recently was: “How to deploy ArcPad to a mobile device, which cannot be connected to my PC/Laptop?”

Well, the standard procedure of installing ArcPad on a Windows Mobile Device presumes that you connect you PDA to your laptop and synchronise it using ActiveSync or Mobile Device Center. Then you can deploy the application using the Deployment Manager Tool. But what if the cable used to connect your device has been lost? Or Bluetooth module is broken?

In this case you can use an SD card (or CF card if your device supports them) and copy the system files across to your mobile device. See the steps below.

Please note, that you have to obtain a laptop or a desktop machine to be able to complete the below steps. Yes, you still need the laptop, as Esri supplies ArcPad as an *.exe file which has to be executed in Windows XP/Vista/7 or 8.

1. Make sure that ArcGIS for Desktop 10 or 10.1 is installed on your laptop/desktop machine and licensed properly.

2. Download and install the latest version of ArcPad. You can download the software for free from the following website: http://www.esri.com/software/arcgis/arcpad/evaluate

This is a full version of ArcPad. Even despite it’s called “Evaluation Edition”, you’re able to use for free but the sessions are limited to 20 minutes. Once you enter the license code, it becomes a full version.

ArcGIS 10.1 Functionality Matrix Simplified

Did you ever take a moment to wonder how many tools and functions are available in ArcGIS?

We know you don’t have time to read all 46 pages of the ArcGIS 10.1 for Desktop Functionality Matrix, so here’s a condensed version to help you decide what you level you’ll need.

If you’re already familiar with a lot of the functionality already and are trying to determine which level is right for you then it’s suggested you read this summary from back to front to give you an idea of what is not included in the lower level licenses. It’s basically aimed at helping you decide when you’ll need a Standard or Advanced license.

Editing an ArcGIS Online Web Map on a Smartphone

Imagine you had a large sales team who regularly visited potential clients, wrote down all of the details of who they visited and then once every week or two came back to the office, hunted around for their notes and then passed them over to an administrator who entered the details into a CRM application. Maybe your team is not in sales. They might be emergency rescue workers plotting where they have been when they are looking for a lost person, or they may be utilities contractors capturing conditional assessment data.

Wouldn’t it be nice if the data was captured out in the field, located spatially at the time and instantly shared with your colleagues? The good news is this technology is already available and Esri has a smartphone app for this. Here is one way you can make use of ArcGIS Online and ArcGIS for mobile: