Importing JPG/JGW files into Bricsys BricsCAD Pro, and transforming the data from EPSG:3857 to a GDA projection using Dotsoft MapWorks
These instructions apply to Bricsys® BricsCAD® V14 Pro. BricsCAD does not have built-in functionality for map projections, but add-in applications can supply the needed commands. These instructions work with Dotsoft's MapWorks® application.
We will describe two alternative methods:
- Attach the georeferenced NearMap image using its world file, then transform the image to the desired coordinate system.
- Use these MapWorks commands: PrjDwgSys to set the drawing's coordinate system first, then ImgWrdIns to attach and transform the image.
Method 1 – Attach First, then Transform
Step 1 (Attach): Use BricsCAD's IMAGEATTACH command from the menu: Insert > Attach Raster Image. Browse to the .jpg image file downloaded from Nearmap. BricsCAD displays the 'Attach Raster Image dialog:
Make sure to tick the checkbox 'Use Geocoding Information'. BricsCAD should find the matching .jgw file and fill in its path. Press OK and the image is attached. Its coordinate system will match the projection you selected when downloading from Nearmap. If the map was already in your projection of interest, you can stop at this step. Otherwise, continue to Step 2.
Step 2 (Transform): Use MapWorks PrjObjTrn command from the menu: MapWorks > Projections > Object Transform.
Select the Source projection (3785 if you did not select a projection to download from Nearmap) and the desired Target projection, e.g. 28354 (which is MGA Zone 54).
Then select the objects to be transformed, e.g. the image. Note that BricsCAD can only scale and rotate images, not 'rubber sheet' them, so the transformation is not exact. A warning message is displayed. The corner coordinates of the source and target rectangles are displayed.
Press OK to execute the transformation.
Method 2 – Set the Drawing's Projection First, then Attach and Transform Images
Step 1: Use MapWorks PrjDwgSys command from the menu: MapWorks > Projections > Drawing System. Use the “System …” button to open the coordinate system selector:
The Coordinate System Select window shows the selected coverage area as a red rectangle in the map. Select a system and press OK, and OK. Now MapWorks knows our target system for transformations into this drawing.
Step 2: Attach the Image using the MapWorks command ImgWrdIns from the menu: Tools > Image > Insert World Rasters. This tool notices that the drawing already has a target coordinate system. It requests a source coordinate system for the transformation. Use the projection you downloaded the image in, which will be EPSG:3785 if you did not choose a projection during download. Several images can be attached and transformed in one action.