Tag Archives: QGIS

In a recent app (form) I wanted to be able to quickly see the last time I had visited a site. This form had the usual Parent/Child setup with a repeatable section that noted information every time I visited the site. Having the ‘last visited date’ on the parent side of the form meant that when I mapped the data in QGIS I could quickly create a categorised thematic by this date to see which sites might need a visit.

Here is the setup

  • App with a repeatable section called ‘observations’
  • Date field on the repeatable section for observation date  – observation_date
  • Calculated field on the ‘Parent’ (non repeatable) side of the app with the following expression

var dates = REPEATABLEVALUES($observations,’observation_date’);
var maxDate;

if (dates && dates.length > 0) {
maxDate = dates[0];

dates.forEach(function(currentDate) {
if (currentDate > maxDate) {
maxDate = currentDate;
}
});

maxDate;
}

If you have a fulcrum account and you would like an example of this, drop me a line via phil@… and I will share an app with you

Open Data – Tasmania

The last few months have seen some changes in the availability of data for those of us that like mapping and other geeky things.

In December, the Tasmanian government started releasing some spatial data via an “Open Data Portal” where its possible to download GIS vector data such as the road network, rivers, streams, lakes, contours and even property parcels. All this data can be used with the QGIS software we are using. Just about every state is now starting to make data available which is great for volunteer organisations working with lean budgets. The data is being released with Creative Commons licencing so be sure to attribute your maps appropriately.

There has also been a change to the supply of TASMAP digital raster maps. These can now be downloaded (but not for free!) from the TASMAP eshop. Each 1:25,000 map can be purchased in a couple of formats that suits both QGIS and Garmin GPS’s. If you have a recent Garmin GPS, such as a 62 model or Etrex then each map can be loaded as a background image. There are some limitations but these can be very handy in some instances and at just $2 a map sheet its not a huge investment.

Of course if you only need an overview map then you can download the whole of Australia as a raster map from Geoscience Australia but be warned, its a huge 3Gb download and that definitely wont fit on your Garmin in its current format.