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Welcome to the home page for the NIWA QGIS User Group. This is a publicly readable web page hosted by NIWA to support users of QGIS, particularly within NIWA, but any QGIS user is welcome!

Why are we here? Based on the understanding that the benefits from any Open Data initiative revolve around data mash-ups and re-use, providing access to a tool allowing people (including NIWA staff) to use all this free environmental data is an important part of any such initiative. QGIS is a core part of NIWA's information delivery strategy - for NIWA staff as well many of our other clients.

Much like the development of easily used and affordable word processing & spreadsheet software for personal computers enabled pretty much anyone to carry out what used to be specialised tasks, freely available desktop mapping and GIS software are enabling their democratisation and widespread general use. Note that we do not envisage QGIS as necessarily meeting all the needs of all GIS users, but NIWA and many other agencies in New Zealand and globally, are adopting tools like QGIS to enable more widespread use of institutional GIS resources, without the traditional expense associated with commercial GIS software.

So, here we are!

2014 report comparing ArcGIS with QGIS

For a formal comparison between ArcGIS and QGIS click here.

This study was undertaken to assess the implications of migrating a specific existing ESRI implementation to QGIS. As such,it compares the capabilities of QGIS compared with existing workflows developed over time around an ESRI installation. For those considering implementing a new GIS system, many of the compatibility issues are likely to be largely irrelevant, as are some other issues (and costs) such as data migration.

This approach obviously highlights the inability of QGIS to work with ESRI proprietary formats, and does not always investigate how a task may be accomplished with QGIS, but undertaken differently from the ESRI approach, although some such situations are covered.

It does compare some advanced analytical capabilities, and in some cases considers the use of plugins & the ability of QGIS to utilise other applications (notably GRASS. SAGA, GDAL and TauDEM) to undertake geoprocessing tasks which QGIS does not support natively.

It mentions the combination of QGIS/Postgis/Geoserver as a better comparison with ARC Server, but does not really consider other open source applications which can also be used to build a more complete open source GIS suite, such as Geonetwork for metadata manangement, or commercial tools like Geocat Bridge to enable a higher level of interoperability between ESRI and the open source/open standards based tools. The ability of Arc GIS to share a native Postgis datastore with QGIS is not described, and some approaches which might use Arc as a central server with desktop access for users via QGIS in a mixed model are also not investigated in any great depth, although the possibility is mentioned.

The report does generally describe the limitations of what it covers, and provides a useful comparison.

Time for next meeting:

Apologies for taking so long to get around to this demo - the next one will not be so distant!

When:          Thursday 4 June 15:30, Allen Boardroom

Topic:           Accessing species distribution and other data from the research trawl database

Abstract:      NIWA manages several research databases for MPI Fisheries, which QGIS can be used to access. This demonstration will show how QGIS can be used to access & display research trawl survey data, eg:

  • one (or more) species from all trips
  • selected species from a particular trip
  • symbols sized by catch size
  • trawls with zero catch of a species
  • survey strata boundaries

These data can be overlaid with topo maps or marine charts, freely downloadable from LINZ.

Anyone familiar with the trawl data, stratified surveys or pretty much any species observation/distribution data should find this useful and relatively easy. The trawl database has several decades of species catch data, which can be accessed and viewed.

An additional feature is the use of the QGIS Action tool (originally developed by Gavin Macaulay of NIWA) to retrieve catch data from the database by clicking on a station on the map - this is particularly useful as it allows users to retrieve non-spatial data reference to a point on a map - the catch data (and underlying catch database table) contains no position data, but can still be retrieved in QGIS.

The demonstration is based around this pdf document - a How-To guide to access research trawl data.


Click to view for a more detailed view of Landcare Research's freely available NZ basemap! (internet mapping with QGIS)

Please feel free to add comments & suggestions.

Questions can go here, but the mailing list is preferable.

If anyone wants to help manage these wiki pages, please let me know!!!

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