Comparing GIS Attribute values to CAD text and update the CAD file

  • 11 February 2024
  • 6 replies

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Parcels are created, removed or changed in GIS,  but we also have a CAD Map3d basemap that we also maintain.  One of these basemaps contains a text layer that has the address number for each parcel, what I am trying to do is compare the parcel address number from the GIS against the cad basemap find out which ones have changed, removed or inserted then make the changes to the cad file.

I have already setup readers for the GIS and CAD parcel polygons and using a change detector I know what is different compared to the polygon basemap, but now I need to take that result and check it against the text in the cad basemap and update it. for some reason the number of changes don’t seem to match when I compre the text.  how would you suggest I attempt to do this, is there something I am missing.


Best answer by evieatsafe 16 February 2024, 17:33

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6 replies

Userlevel 4
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I’m not 100% sure that I understand what the challenge is here - but if you need to get the text value linked with the polygon you can try and use a PointOnAreaOverlayer to get the address as an attribute? The NeigborFinder is also a good option. 

It’s a bit challenging and messy though as often in a CAD drawing the text might lie outside the parcel pointed to with a leader.



Badge +4

I have isolated My problem with the results but I still have a further question.

First off to explain this better:

We have the street number in both GIS (attribute value of parcel) and in AutoCAD Map3d object data, in CAD we have several basemaps one with the polygons for parcels and another that has all the text of our basemaps.

I have isolated the changes between our old cad polygon file and the new GIS polygon data, now what I am trying to do is then take the resulst of the inserts and deletes and then write the inserted text to the right cad layer and then also delete the cad text fields that I no longer need.

Userlevel 4
Badge +25

It’s not so easy to “update” a CAD file. In saying that FME does support providing a template file when writing out cad data which mean you should be able to keep all your layer names and properties.

@andreaatsafe - do you know if it’s possible to “update” a CAD layer? 

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I have in the past created a cad layer, that look exactly like it should in cad from gis data, but this is in creating a new cad drawing with a styler and writer, but what I am trying to find out is how to edit an existing cad drawing to add new and or delete text without overwriting the entire drawing, just the spatial text.

Badge +14

Hi @nick_a & @virtualcitymatt I do not believe it is possible to ‘update’ a CAD file like you would with a database. Your best bet would be to use a template file like Matt mentioned, then write out both the existing unchanged data and the new or updated data at the same time. Everything you would like deleted you can omit from the writing process. 

Badge +4

Thank you all for your replies, I was hoping since the text was spatial that maybe there was a way to edit it, but alas, it doesn't seem to be.  One of the reason I was hoping to edit the parcel text, is that sometimes the editors will move the text that is in the way of our schematics, so just deleting and updating will remove any of their edits and they don't want that to happen.  I think what I am going to do is export cad drawings for the deletes and inserts in separate files that they could query in and make the appropriate changes after review to the basemap.