GDA94, GDA2020 and WGS84; The projection dilemma

Progress supporting GDA2020:

The Intergovernmental Committee on Surveying and Mapping (ICSM) & Geoscience Australia (GA) recently released the definitions for the GDA2020 datum and associated projected coordinate systems covering Australia and its territories. Esri Australia has been working closely with ICSM & GA to ensure that ArcGIS software products support the new definitions.  Version 10.6 of ArcGIS and version 2.1 of ArcGIS Pro both include support for the new datum and projected coordinate systems (you can learn more in the Esri Australia Technical Blog)

Avoiding alignment issues mixing datums:

Web GIS, by default, displays data in the projection WGS84 Web Mercator (auxiliary sphere). When mapping data is shared to ‘Web GIS’, data is automatically reprojected ‘on-the-fly’ to this web projection in order to align with the displayed basemap and fit with the global projection. Most users do not realise that their data is being reprojected and in many instances occurs without issue.

However, while organisations are migrating to GDA2020 from GDA94 and using mixed data containing both datums, these mixed data sources will create a challenge when displayed in WGS84. The issue occurs when data is reprojected to the WGS84 Web Mercator projection.  

GDA2020 & ArcGIS

 

It is now official on the 15th of December 2017 Geoscience Australia and the Intergovernmental Committee on Survey and Mapping (ICSM) launched the new GDA2020 datum.

In support of the new Australian datum, the following tools and resources have also been released by Geoscience Australia and ICSM:

·       the ICSM GDA2020 Technical Manual;

·       additional ICSM datum modernisation Fact Sheets;

·       GDA94 to GDA2020 Transformation Grids;

·       Geoscience Australia’s GDA94 to GDA2020 Online Transformation Service; and

·       AUSGeoid2020 to convert GDA2020 ellipsoid heights to the Australian Height Datum.

So what does this mean for the ArcGIS product suite? Well from ArcGIS Pro 2.1 and ArcGIS 10.6 onwards all state, territory and national projections that incorporate the GDA2020 datum are supported.

Georefencing workflow made easier with ArcGIS Pro

Do you often have to georeference raster datasets? Do you find a lot of time is consumed with setting up control points?

Georeferencing was introduced with ArcGIS Pro 1.4 and has the capability to speed up your georeferencing workflows. Auto georeference allows you to automatically georeference your raster dataset to a referenced raster dataset (this can even be a basemap from your Portal or ArcGIS Online). The automated control points are based on the spectral signatures of different locations across the images, so this method is best suited for aerial and satellite imagery which are similar in nature.

R-ArcGIS Bridge – Improving methods of statistical analysis in ArcGIS

The R-ArcGIS Bridge is a little-known secret to improving your methods of geostatistical analysis. By integrating ArcGIS and R you can have the best of both geospatial and statistical platforms. With the R-ArcGIS Bridge you and I can now perform and visualise comprehensive statistical analysis directly in ArcGIS Desktop.

 

Why would you use R?

R is a powerful platform for solving big data science problems. R is both an open source language and programming environment, widely used for statistical analysis. R offers an online repository with 6,400 statistical problem-solving packages.

The R-ArcGIS Bridge is a way to load your spatial data into R, or, create custom Geoprocessing Tools in ArcGIS that leverage the capabilities of R. The Bridge can be directly connected to either ArcGIS Pro (version 1.1+) or ArcMap (10.3.1+), and R (3.1+) or RStudio. The R-ArcGIS Bridge can then be used with pre-existing tools written in R, without the need to learn any code!

There are several uses of R-ArcGIS Bridge:

• Use R functions to read and write spatial data
• Convert between data types
• Solve complex geostatistical problems
• Write, configure, and modify an R script to be executed from a Geoprocessing tool
• Share an R script with others as a toolbox

 

How do I get started?

ArcGIS Pro for Imagery Analysis

In previous blogs, I have spoken about how imagery can be utilised within the ArcGIS Platform and how it can be analysed. Through all this it has been about imagery can be viewed downstream. What about the prepossessing or specialised analysis not through web services? Well this is where ArcGIS Pro comes in.

In 2017 Esri has stated that their goal is for ArcGIS Pro to be functionally equivalent or better than the current toolsets in ArcMap. To this end in ArcGIS Pro 1.4 Esri have included a new core tab, Imagery. Core tabs are always on and accessible unlike layer specific tabs which only appear when an entry is selected in the Table of Contents.

Space and Time Cluster Analysis – Can ArcGIS help predict the future?

Everything happens at a place and occurs at some point in time. Space time analysis seeks to understand when and where (and sometimes why) things occur. With the evolution of ArcGIS Pro we now have the opportunity to not only successfully analyse patterns of time and space, but also immerse in a deep 3D visual experience.

ArcGIS allows you to exploit the space and time aspects of your data, allowing you to answer questions like:

1. Is there an emerging hot spot?
2. Are there any anomalies?
3. Where your decisions or resource allocations effective?

Several tools, including Create Space Time Cubes, Cluster and Outlier Analysis, Emerging Hot Sport Analysis and Grouping Analysis assist with answering these difficult questions. So, let’s explore how we can utilise some these tools to analyse earthquakes that have occurred across South Australia. The quake data was sourced online from Geoscience Australia as a csv, recording the last 58 years of earthquakes across the State. Which I then subsequently created a feature class.

Viewing space time cube in ArcGIS Pro

ArcGIS Pro: Lets be animated!

ArcGIS Pro is one of Esri’s new desktop mapping application. With ArcGIS Pro we have the ability to represent and display our spatial information in new and exciting ways. I thought I would spend a minute stepping you through animation in ArcGIS Pro. ArcGIS Pro’s animation toolset allows users to create visually exciting products, as the animation tools can be used in either a 2D map or 3D scene.