Microsoft SQL Server Report Designer Error: An item with the same key has already been added

Wednesday, 23 October, 2019

Whilst designing a report for deployment to SSRS from Visual Studio 2015, I received this error message when entering a SQL query I knew worked in to the New Report wizard:

An error occurred while the query design method was being saved. An item with the same key has already been added.

This is a classic Microsoft error message that is both specific and vague at the same time… and also shouldn’t happen. There are scant details online as to where this comes from but is a result of Microsoft SQL Server Report Designer having a requirement for unique column names (even if the underlying SQL query returns unique columns with the same name). This is a stupid limitation and whilst the error message is accurate, it is sufficiently vague to obfuscate what is going on.

The solution - unsurprisingly - is to make sure that there is no repetition in the names of the columns.

Grouping Objects in Visual Studio 2012

Monday, 14 October, 2019

Grouping objects should be one of those things that is - well - easy to do! In Microsoft Word you Ctrl select each object, then right-click and select “Group”. Easy. In Visual Studio 2012, not so. You would have thought that, in Microsoft’s prime programming environment, these simple layout tasks would be easy, but thy’re not and it’s not documented anywhere. In my particular instance I was creating a SQL Server Reporting Services report where images in the template were moving depending on the number of rows in the output. The solution was to group the images together.

The grouping concept is sensible and well implemented, it’s just that working out how to do it is difficult! You actually have to insert a new rectangle object and then drag-and-drop the objects you want to group in to it. Once you’ve done this, the properties of your contained objects should look something similar to this where the “Parent” attribute under “Other” shows “Rectangle”. Now if you move the group, they all move. Job done!

rectangle_properties.jpg

ISO 3166-1

Wednesday, 2 October, 2019

ISO 3166-1 just trips off the tongue, however it’s one of those standards that underpins a fair amount of daily geospatial traffic that is undertaken on a daily basis. Yes, I’m talking about country codes which Wikipedia helpfully defines as:

ISO 3166-1… defines codes for the names of countries, dependent territories, and special areas of geographical interest

This is important because it is used in so much analogue and digital data exchange between countries, although don’t for a moment think the ISO is the only organisation that defines country codes… but that’s a whole other blog post!

What gets in included in the list is interesting… the criteria for inclusion include member states of the United Nations, a UN specialized agency or a party to the Statute of the International Court of Justice. Becoming a member state of the UN is clearly helpful, although what makes a country is interesting in itself, as well as highly politicised. Palestine is an obvious example, but just look at the UK. The UK is a country, but should Wales, Scotland, and Northern Ireland also be included? For example, they are included for FIFA. The UN loosely uses Article 1 from the Montevideo Convention which outlines four qualities a state should have: a permanent population, a defined territory, government, and the capacity to enter relations with other states.

Anyway, once you are on the ISO 3166-1 list you get 2 and 3 letter codes, along with a 3 digit numerical code. These are maintained by the ISO 3166 Maintenance Agency and, given the above, change regularly. You can view the current list here and subscribe to official updates.

At the RGS we are a membership organisation and take online international payments, so having up-to-date country codes is important. Rather than subscribe to the ISO, we use the UK government Country Register, which includes an update service. It has the ISO-2 letter codes, although isn’t necessarily identical (as it’s countries the UK recognises).

EGU 2020 Short Course: UAV Data Collection and Analysis: operating procedures, applications and standards

Tuesday, 1 October, 2019

UAV Data Collection and Analysis: operating procedures, applications and standards
Conveners: Paolo Paron; Co-conveners: Mike James, Michael Smith

UAVs have reached a tipping point in geoscience research such that they are near-ubiquitous and commonly used in data collection. In this way they are opening new ways to study and understand landforms, sediments, processes and other landscape properties at spatial and temporal scales that is close to the scale of the processes that operate. However this implies that non experts are entering the field of photography, image interpretation, photogrammetry and 3D modelling often without a solid grounding in the principles of surveying. This course aims at providing a solid foundation for UAV users in order to avoid simple mistakes that can lead to legal restrictions, UAV loss, operational problems and poor quality data.

We will introduce pre-flight, in-flight, and post-flight procedures that aim at optimizing the collection of high quality imagery for subsequent downstream processing. We will also demonstrate the analyses of data by means of existing state of the art commercial software, such as Pix4D and Metashape for point cloud analysis, and eCognition for object based image analysis. We will also demonstrate the use of open source/open access software like Cloud Compare and Orfeo Toolbox