I’ve already blogged a couple of times about the BGT-project which I’m working on lately.
Structuring of the data goes very well, the first test-migrations with AcClassify into the Oracle Spatial database has been successful last week and the data can be viewed in ArcGIS-desktop and the webviewers.
That I was clumsy enough not to config the database limits properly and that the Oracle tables have to be registered into SDE, that’s peanuts 😉
They’re looking over our schoulders from the various local & regional discussion groups, because the BGT keeps ( almost ) everyone busy these days.
In two weeks there is a meeting where people from Geonovum – the brains behind the IMGeo-model – will attend as well, because they are very interested in feedback from the field.
In my previous post AutoCAD Map – Break, Trim and CleanUp I’ve blogged about the process to structure the drawings.
This blog is about classification and creation of the polygons.
First we’ve created the centroids, AutoCAD points with attribute information in conformity with the IMGeo-model.
Such a centroid for a Wegdeel contains for example attributes like IDentificatie, objectBeginTijd, status, relatieveHoogteligging, typeWeg etc.
Next to it there are centroids for Spoorbaandeel, Waterdeel, Terreindeel, Kunstwerkdeel and Pand. These Pand-objects come from the Basisregistratie Adressen Gebouwen ( BAG ) by the way.
Further a Polygon Topology has to be created. Herewith we also use a Wizzard interface, where the structured linework are the links which the centroids are joined.
If there are lines not properly closed, than the Topology process comes with an error. Likewise if centroides are missing or double.
The Topology model is converted into MPolygons, with the IMGeo classification from the centroids copied to them. These MPolygons are migrated as polygons into the Oracle database using AcClassify.
more about that in the next post
In my previous post from AutoCAD Map DWG to BGT conform IMGeo I’ve blogged about a project where we have to migrate linework in drawings into polygon-objects in a database.
These are drawings along provincial roads, including the roads, cycle-tracks, ditches, terrains etc.
On top of the topography the cadastral parcel lines should be inserted. Inside the parcel is the data that should be structured, because this is the area that should be maintained by the province for the BGT.
The area outside the parcel polygon should be maintained by the municipality that owns that area.
Using Boundary Break the topography and the parcel polygon can be brooken against each other. And using Boundary Trim the inside & outside can be seperated.
To structure the area inside the parcel polygon we’re using the standard CleanUp functionality inside AutoCAD Map.
Using a Wizzard interface we can select the elements that needs to be structured, next we need to set the cleanup actions in a specific sequence with their respective tolerances that needs to fit to the accuracy of the material.
All cleanup settings should be carefully tested and can be stored in a cleanup profile to re-use these setting in the next drawings.
in my next post I’ll blog about polygon creation including IMGeo classification
Currently I’m involved in an AutoCAD BGT pilot project. The motivation for this pilot is the introduction of the Registration Large Scale Topography ( BGT ) conform the classification-model of Informationmodel Large Scale Geography ( IMGeo ).
To migrate from linework in drawings into polygon-objects in a database, the lines that’ll become the boundaries of the polygons have to meet certain criterias.
The lines have to connect to each other. Is one of the lines to short, than there might be an undershoot. Are the lines crossing each other and is there no node on the crossing, than there might be an overshoot.
In both cases the lines have to be cut and a node has to be made. Otherwise we cannot create polygons.
AutoCAD Map has CleanUp functionality to perform those cleaning operations (semi)automatically and Topology functionality to create the polygons.
in the next posts I will dive into more details of this workflow