FME: Not just for ETLBryan HallSpatial Software Engineer

Quick Bio

Started with Intergraph MGE and AutoCAD for the USAF.

Developed GIS telecom documentation systems (GIMS, CVC) for the USAF and USMC. Created a remote sensing product for DoS

Working with augmented reality to project utility locations “into” the ground. Continue to support CVC

Intro to Geospatial1990-1996

Contract Work1996-Present Current Work

Problem: Client needs AutoCAD drawings but the app produces only PDF’s of technical diagrams.

Task: Make projected AutoCAD

engineering drawings from

geodetic spatial data

We all know FME is great for ETL work. But… can it be used to generate engineering drawings including labels and title blocks?

Starting point:

Oracle databaseEPSG 4326 datasetPre-made Java-2D based screen drawings

End point:

Autocad 2012 DWG fileLocal projection, usually UTM or State PlaneDistance in Feet or Meters

Turn This…

Into This…

For print!

Hey, it’s not THAT bad…

Issue #1 – RotationEngineering drawings typically do not show North as “up”. Instead, the world is rotated around the center of the item of interest so it looks and fits good. However, we will have to rotate EVERYTHING we transform or create around this point

Rotator is perfect for this task

Issue #1 – Rotation (cont)

Issue #2 – ProjectionAlthough the source data is global and geodetic (EPSG 4326), the target sites are planar and the coordinate projection is unknown to the FME worksheet prior to running. Fortunately, we can pass the projection we want as a command line parameter – and let FME’s awesome projection engine help us place the AutoCAD objects at the right locations.

For this, we use Reprojector

Issue #2 – Projection (cont)

Issue #3 – ScaleEngineering drawings are scaled to best fit that item with some whitespace for labeling parts, not a set scale. The overall scale IS a given parameter – but isn’t quite right due to page size / font size changes for Java screen fonts VS. AutoCAD page size and fonts (the output target). We have to correct for this as well

For this, we used math with relative offsets to create a scale value

Issue #3 – Scale (cont)

Issue #4 – ClippingWhen the bounding box of the area to display is computed – we will need to clip everything that extends past this box so that we have clean edges to insert into the diagram

Clipper is our friend here

Issue #4 – Clipping (cont)

Issue #5 – LabelingIn the application, labels are created for a drawing – but not stored spatially (there are no pre-made leader-line geometries to copy to AutoCAD).

Also, the text for the labels in the Spatial application are generated on-the-fly, so that will need to be fed to FME via a view that calls a package to create them

What͛�s This?

Issue #5 – Labeling (cont.)So… just use the FME toolset to create AutoCAD labels on the fly – right?

Unfortunately, there is no native specific labeling toolset that makes AutoCAD labels. Yes there is the MapTextLabeler plugin – but even if we had that, it doesn’t take specific leader coordinates as input.

Time to roll our own…

Labeling – Breaking it down…What’s a label consist of?

1. A location on the item it is referencing2. A location where the leader line connects to

the text box3. Text – usually multiline in our case – which

will turn out to cause a big headache

Making a Label1. Given the location on item it is

referencing determine which direction the leader line goes so we know which side to put the text on. Does it go from right to left, or left to right?

Making a Label (cont)2. Create the leader line

Making a Label (cont)3. Since AutoCAD draws multiline text from a center point (not top left or top right), count how many rows of text there are so we can calculate an offset (Python)

And… then the title blockEach diagram gets a boilerplate title block (created by the worksheet). This is composed of lines and text to replicate the original AutoCAD drawing look. Each of these lines and fonts has to be rotated and scaled to fit for the drawing location and size. Each item uses a relative position offset for it’s coordinate

And… a scale barRight – so where is that transformer tool?

Darn, no such thing seems to exist (yet). Time to make our own from scratch. Here we will go with 1, 10, and 100 Foot graticules depending on the drawing scale.

And… a scale bar (cont)

You want a legend too?Fine… for each type of item depicted, calculate the relative position, symbol size, and font size

Honestly, once I’d done the rest – this was pretty easy!

Can I see it yet?

Two – Linked Worksheets

Setup…

…and Run

Engineering tags are stored in Oracle workspaces. But to set the workspace for the entire workspace, its name first had to be extracted. So for order of operations, we used linked FME workspaces

WHY?

Demonstration Time…

(AKA Murphy Time)

Thank you!Bryan HallQuestions – email me at:frankencorrado@gmail.com