QGIS

QGIS 3.4 is out

rjhale · Nov 1, 2018 ·

…..And you’re saying “WE ALREADY KNOW THAT”…….. Well – maybe you didn’t.

If you’ve been keeping up with all the excitement you’ll know that QGIS releases often. Every release features new functionality. The release schedule got to be a bit much for some – so a LTR (Long Term Release) was produced that is stable for one year. As of right now the stable release is the 2.18 series.

QGIS publishes their release schedule and it more or less stays on target within a day or two. If you’ve been using 2.18 religiously there’s a good chance you’ve been using it for well over a year (maybe 2?). 2.18 is stable. 3.4 is going to be the next LTR in February 2019. You may want to start testing 3.4 to see how it fits in your workflow and projects. Why?

If you haven’t used the 3 series yet it’s different. New python version, new processing toolbox, new everything. Different – but not enough to make you scream – but possibly enough you may want to play with your workflows a bit.

How different?

Plus you may have some plugins missing that haven’t been ported over from 2.18. So you may want to start bugging your favorite plugin author and think about possibly sponsoring the migration (if it hasn’t happened).

Most of my clients have stayed on 2.18 so I’ll be pushing them over the next bit to migrate.

So Download the new version and have some fun with it!

Editing your data in QGIS

rjhale · Oct 24, 2018 ·

It has been a while. I’ve had a running project in PostGIS now that is 4 years old. It ends this month. It spent 3 years as a shapefile and one year as a File Based Geodatabase before I decided to “learn hos this postgis thing works”. Having a running project last for that long is a bit rare on my end. With that ending other things are starting up which is nice – because I tend to seek out a comfortable routine and don’t push myself.

Flash forward to this month’s fun. Sixty one columns and 22,000 something points. Not that insane – but editing is a bit of a chore. AS you’ve got 61 columns of stuff. Do they edit all 61 columns? No.

I did the new standard routine of loading QGIS/PostGIS/Geoserver/Fulcrum and we were off and running. As it turns out it had been a while since they had edited and the backlog was filling up.

Part of the fun of a new client is learning their processes. One the first things we did is start editing data. This can be a bit unnerving for new users:

You get all 61 columns in one menu upon adding new data. The cool thing with QGIS is there’s a good way to reduce the choices using the tools you’re provided. If you right click the layer in the Layers Panel and go to Properties and then to Attributes form you’ll notice at the very top you’ve got three choices. The first being just use the default. The second would be the drag and drop designer. You can remove the things you don’t need to edit. So just start clicking that minus button on the form layout. Yes I just randomly removed a bunch of stuff as an example.

You can now edit things with a little bit less confusion.

So now when you add a point:

BUT…..What if you want a less confusing menu for editing? YOU SAID THREE CHOICES FOR MENUS AND YOU ONLY MENTIONED TWO. Part 2 is coming…..WHY DIDN’T I INCLUDE IT NOW? Well….my posts are too long as is…..

20 minutes at the East TN TNGIC Meeting

rjhale · Sep 6, 2018 ·

I went through a year or so of not talking at conferences. For local ones I’d show up and do something. I taught a workshop at FOSS4GNA 2018. I did a workshop at FOSS4G 2017 in Boston (and it sorta sucked). I need to get out of that mode and talk more – but I’m happier being quiet these days and working with clients.

Anyway – at FOSS4GNA 2018 I discovered something – the OSGEO Suite had disappeared from Boundless’s Website and was replaced with a github repository. It wasn’t long after Don Meltz put up an excellent explanation of the OSGEO Suite. The OSGEO Suite being gone isn’t a problem. It does increase the amount of talking I have to do spend explaining it’s not a problem. I could even compile the suite – but my clients can’t. They are smart people – but the time to compile the boundless suite won’t be happening.

One of the things I keep running into is the idea of an Open Source Server. The OSGEO Suite was well known and I get people asking “Hey – can you set us up a geo server”. They mean the opengeo suite. I then launch into an explanation of what makes up a “geo server” and they go a bit blank and answer me “Yeah – one of those”.

So for the next bit I’m gonna be doing something like this:

I want to explain how this works to people. We’ve gotten a bit deaf by hearing “ArcServer” at every conference in TN as this one monolithic thing you have to install to make a web map…which really don’t need since AGOL appeared but…you want SDE and it’s not called that and you have two people editing but you need SQl Server but you don’t….

Anyway, QGIS/PostgreSQL/PostGIS I’ve installed multiple times and as of late I’m experimenting with geoserver and what it can/can’t do. I have no grand delusions of creating ‘Randy’s Open Geo Spatial Super Duper Server’. I want to get to the point where maybe mapserver is an option in this. So much to learn…so little time.

I suck at github – but I’ve been more active as I try to develop a skill set and get over the angst of pushing and pulling things. I’ve built a vagrant box to install PostGIS/PostgreSQL/Geoserver so I can have something to point at plus it gives me a starting point for an upcoming class I’m in the middle of building. The vagrant box isn’t pretty – I expect to change it over the next bit as it’s mostly pieced together from a lot of other people’s work (Coleman McCormick, Dave Smith, etc). It works though and I have everything but pgadmin 4 running in one spot. Which – I don’t think this is anywhere near “install this for a server” because this is mostly just for talking, training, and testing.

So why vagrant? Why not docker? I can gloss over vagrant faster at theses talks than I can docker. I have 16 minutes to draw diagrams and about 4 minutes to publish one piece of data: QGIS -> PostGIS -> Geoserver -> Leaflet.

Anyway – if you’re up for the possibility of a train wreck of a presentation come by the East Tennessee Meeting in Kingsport next week as I try to explain how this works and hopefully you get excited enough to install some or all of these components and do something cool with your data.

OSGEOLive 12.0

rjhale · Sep 6, 2018 ·

So for those of you going “HEY I WANT TO USE SOME OF THIS OPEN SOURCE SOFTWARE?”. Maybe you can’t install it locally…or maybe you have a spare machine laying around – there’s a way for you to do it.

Download the OSGEOLive image and run it as a virtual machine or boot your computer into the Distribution. It’s a Linux operating system with about 50 plus free and open source geospatial applications.

They put a ton of effort into releasing this as a showcase of the software in the OSGEO realm. So give it a run and test out software you have questions about.

Adding Triggers to Geopackage

rjhale · Aug 30, 2018 ·

In between work I get a chance to play around with software. I’ve been digging around postgis more and more these days trying to get a better understanding of what it will do or won’t do. It’s a never ending learning experience for me. Sometimes it pays off – the never ending tutorial left me suggesting we dump a database to a geopackage.

I’m great at using geopackage in sentences like “USE GEOPACKAGE” and “Hey – what do you think about geopackage?”. Since I’m actually officially using it I decided to do some digging. It’s a SQLite container. Since it’s a SQLite container I should be able to do some things with it – like…..

I can use the spatialite gui and throw SQL against it and change the tables.

While talking to another person the question started with ‘Well – why can’t we just do the data collection in geopackage?’. Which we did some back and forth and in some cases this would be acceptable vs doing a full postgis install.

So my first question is: Can I make a trigger in a geopackage? The answer is yes. For those of you who don’t know what a trigger does – it responds to some action in a database. In postgresql, I put multiple triggers in a database for a client. Some triggers calculate lengths and some areas and some make a note of who edited a feature.

After some digging I found the syntax and wrote a trigger for SQLite/Geopackage in the form of:

CREATE TRIGGER update_esn AFTER INSERT
ON addresses
BEGIN
update addresspoints set “esn” = (select esn from polygon where st_within(new.geom, geom));
END;

I used the spatialte gui to add the trigger. So if I pass this off to a client they can edit an address and have it automatically pull in the emergency service number. Magic? Eh – close enough for me.

While it’s not going to work for a multi-user situation (or will it – I’ve not investigated) – it works. So now I’m adding widgets to QGIS to aid in data collection.

QGIS

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