Using 3D BAG in QGIS 1: an introduction

[Music] hi i'm eric and in this short video i will show you the basics of loading the 3d city data in qgis recently the 3d geo information group at the tu delft showed the world a countrywide 3d registration of buildings and addresses your first entry is a viewer that shows old buildings in a fast and intuitive way and allows you to identify buildings heights and roof angles the viewer also functions as a kind of a download portal for the underlying data so let's have a look at that first so here we have the viewer you can use your mouse the left click to pan and right click to rotate in different directions as well the scroll wheel can be used to zoom in or out if you're looking at one of the buildings you can point and click just at any part of the building it will give you immediately a height and an angle of the specific surface that you're clicking on as you can see you get some kind of pointer that is perpendicular to the actual surface that you're clicking on again you can see the angle and height of the exact place where you clicked apart from that you can also open the attributes table there's a few extra attributes here but one of the interesting things is that you could also download immediately the towel that includes this building if you go to the download page you find that you can use the city json object files or geopackages let's download the geopackage first as that is the format of choice for most qgis applications the tile i've downloaded is here on my desktop and opening a geo package in qjs is really easy you can just drag and drop this on the map canvas here you can see the different level of detail data sets that we have so let's go for the highest level of detail that is available as 3d buildings and let's open that and that shows you immediately the buildings as a 2d projection it is really easy to get a 3d view out of this because there's a 3d viewer incorporated in qjs nowadays so one of the things we have to do is we have to look at the 3d view and you see it is not symbolized yet so we'll just make a very simple visualization out of that using single symbol it will come in grace and let's have a look at that so we open a 3d map view and if you look at this one you can see it is a typical 3d view using control you can rotate in different directions here and you can see the building of architecture again as a 3d building identifying one of these buildings will give you very short list of well not too interesting information so in the geo package the information is not complete you don't see any roof heights or angles so we have to get back to the city jason to get that right so let's get back to our download site and also download the city json for this purpose switch this one off and as you can see this was the building that we've been identifying earlier so let's switch it off because it really looks terrible all those red lines so especially for this purpose there's a plugin the city json loader which is written at tu delft as well you can see install this plugin and it will come in three different ways it will come into a processing tool there's the city json loader there's also a button here and it is under the vector menu so you really can't miss it if you want to download this one you can see this is the latest i've downloaded it will automatically read the parameters for the json properties coordinate reference system and everything is there there's just a few parameters that need attending to so here we have split layers according to object type that would be very nice but the only object type in this specific data set is building so it's not really of much use the level of detail as we've seen in the geopackage there's a few different levels of detail for every object we can put them as an extra attribute so you have an extra field including the level of detail in your table or you could set up the different lods as separate layers and that's what we'll do now now the semantic surfaces are interesting as that will make automatically a styling for roofs for doors windows walls etc so let's add that too let's load this one and see what happens as you can see there is now three different data sets included in the layers panel we'll just have a look at the lod 2.2 which should be similar to this one so if we use this one now for a 3d visualization we could add a new 3d map view and a 3d map view here as you can see it already has let me check this it already has different coloring for the roofs and for the walls you can see here in the layer styling if you look at the 3d objects that it is a rule-based styling based on the semantic surface in this model this model allows for windows and doors but the actual data doesn't have that so you won't see anything changing there there's one more thing here and that is that if you look at the ground it is not really a crisp line here and it is because you're looking at the same time you're also looking at a as a ground data set so let's have a look where that comes from well it's not that hard if you know what you're looking for so let me show you if i switch off the wall surfaces also the ground surfaces and you'll find that you can still see the original 2d drawing as well so it should be found somewhere in the 2d data so i'll switch the wool and the ground surfaces back on again and i'll move to the 2d data now if we don't show the 2d data then you'll see that all the little carved edges disappear now you have a smooth transition between the wall and the ground you might say that this is not really interesting because you don't see what's on the ground so we could add a specific background for example and now you see the the buildings shown on the map so this is all nice and we have a kind of a interesting visualization here which you can play around with and rotate and look at different angles and but it's just playing around and there should be more to 3d data so that is something that we're going to do in the next video enjoy more 3d fun with geodata

Channel: 3D geoinformation research group @ TU Delft

Views: 7,870

Keywords: 3DGeoinformation, QGIS, TU Delft

Id: hvVZm6qgLD0

Length: 8min 40sec (520 seconds)

Published: Thu May 20 2021