Is the correct coordinate zone showing up in the Civil 3d units and settings dialog? When you say the drawing is upside down are you referring to the geomap import? Thanks.
Hi France,
You can re-project the surveyor's Lo System drawing to a projection with a North Up orientation. >>>Link<<<.
Dave
Dave Stoll
Las Vegas, Nevada
NVIDIA Quadro P5000 16GB
Windows 10 Pro 64 / Civil 3D 2024
i am also in south africa and deal with Lo Coordinate Systems every day. i would not suggest that you change the survey in any way, if you need to give setting out on that project you will want to give back work that matches the survey format. Just do a transformation.
Ensure the reference point values is made 0.
Click apply and if you go to your maps you will see that you should be in the correct place now.
Here is my experience with working with RSA coordinate systems and how we tackle this problem.
Due to our X and Y axes being flipped compared to most coordinate systems this causes problems when working with international software. Traditionally Autodesk and ESRI did not have any coordinate definitions that handled our "South Orientated" coordinate system.
Surveyors usually give us survey files either of the following formats:
- The X and Y CAD coordinates look good (CAD Y, our X is positive) but the entire drawing is up side down with north at the bottom. Some surveyors will flip the camera so it looks like north is up but it is just the camera that has been rotated 180 degree. Here is an example, notice the cardinal directions around the view cube:
- The surveyors give us the drawing with the CAD coordinates negated, so surveyed X becomes negative CAD Y and surveyed Y becomes negative CAD X. This results in north being up. Some surveyors will place a ucs to negate the coordinates so that they look like the coords in point 1 above but on the WCS they are negated. Here is and example of this setup, notice the negated coords at the bottom but north pointing up:
The way we prefer to deal with all of the above is to transform the survey into the following format:
- Remove any UCS and rest the camera to view the WCS (basically rest everything about the view to normal).
- Make sure north is at the top of the screen. So either the survey will be fine as is or you will need to negate by rotating everything 180 degrees around the 0,0 point in the drawing.
- Set a custom coordinate system so that the drawing properly interacts with the Bing maps and importing/exporting GIS information. I created a set of custom coordinate systems (one for each band or longitude) that are just a copy of the built in systems with the quadrant directions flipped (West -> East and South-> North). You can see the comparison in the images below.
Built in WG19 system:Custom WG19 System:
The benefits of doing the above is that Civil 3D will play nicely with any other GIS system and online map, and most georeferenced aerial imagery when using MAPIINSERT or similar. As I said before older software (and still a lot of new software) do not know how to deal with our South Orientated system and doing the above lets everything work well together.
The down side of this is that if you read any coordinates from your drawing you MUST remember to negate them (just multiple the X and Y by -1, so 1000,-3765000 in CAD is actually -1000,3765000 in the real world). An easy way to check if you are giving our the correct coordinates is that the larger coordinate (the X coordinate) is always positive in South Africa, so just make sure the larger one is positive and if not multiple the X and Y by -1. Another problem that you will run into it that if you produce tables of setting out coords for pipes,
structures, cogo points, roads, etc. you will be displaying the wrong coordinate. In our template we have created styles that negate the coordinates automatically so everything looks fine on paper. If you are going to make your own styles you will have to make use of expressions to negate the X and Y coordinates and then use the expressions in your tables, labels, etc. The South African Country kit uses the same method as you can see in the image below:
I hope all of the above helps. I also have attached the a zip containing 2 PDFS (the forum will not let me upload PDFs directly for some reason) that explain the coordinate systems and of particular interest is the last pages of each PDF that explains how to use our coordinate system in software.
Bonus tip: Most surveyors use model maker and when they export the survey to a DWG the software does not set the drawing unit correctly and leaves all the units as the default which is feet. If you are copying and pasting or xreffing the surveyor's drawing and it falls on the wrong place check the units.
Hello @37230778
Yes, @Kyle-L has the right idea.
Here's the down-n-dirty way you can perform to make north point up (it's the same as the @Kyle-L method outlined in Post #6 of this thread).
1. When using Harbeesthoek94.Lo31 Bing Map Hybrid will look like this. See image-1.
2. Go to Geolocation Tab=>Location Panel=>Click Remove Location=>Yes. Then, on command line =>MAPCSLIBRARY=>Enter. In the Coordinate System Library, do as shown below. See image-2.
3. In the Coordinate Section, rename duplicate coordinate system to Hartebeesthoek94.Lo31_B. See image-3.
4. In the Parameters section, do as shown below. It may take a few seconds after clicking 'Save' button. See image-4.
5. Back in the Coordinate System Library, select the duplicate CS you just created=>Assign button. See image-5.
6. Go to Geolocation tab=>Online Map=>Select Map Hybrid. North will now be pointing up. See image-6.
This is a zoomed-out view when using Hartebeesthoek94.Lo31. See image-7.
This is a zoomed-out view using Hartebeestheok94.Lo31_B or the Duplicate coordinate system. See image-8.
A test point was inserted at Lat -30.739246, Long 30.457613 with modelspace using the Duplicate coordinate system. Both x and y coordinates are positive. The geographic Lat/Long is shown in the Location section. See image-9.
While modelspace was assigned Hartebeesthoek94.Lo coordinate system, a test point was inserted at the same Lat/Long position. In this drawing, the x,y coordinates have the same value BUT are negative. See image-10.
Summary:
- If you have received survey data from a surveyor in Hartebeesthoek94.Lo31, keep the original orientation.
- To make your drawing oriented so North is up, create a DUPLICATE of the original coordinate system.
- Then using the DUPLICATE, Draw your points and lines then save it making sure it's saved with the Dup CS and a new name.
- If you must send a drawing with your additions (or revisions) back to the surveyor, open your saved drawing, 'remove' your Dup CS, then re-assign the original coordinate system back to the drawing. Be sure to re-name this drawing (the one using his original CS) a new name so you don't over write your drawing (which uses the Dup CS). The drawing you send back will display Bing Map Hybrid upside down, but that's OK. North pointing down is same orientation as the drawing you received to begin with and it will 'match' your surveyor's orientation and his coordinate system.
Chicagolooper
