How can I plot Lat and Long coordinates into AutoCAD

[Anonymous]

I have a csv file of Lat Long coordinates that I would like to plot onto a map in AutoCAD 3D. Currently we use this data to plot points into Google Earth but would like to transition to directly plotting into AutoCAD. The attempts I have made never scale the points correctly (They plot in a MUCH smaller scale compared to a map). Any help is appreciated

[ChicagoLooper]

Hi @A_HULL-2021 

 Based on the map you uploaded in post #16, this is your site, correct?

If the image above is correct, then you can have a geo-ref'd drawing.

[A_HULL-2021]

Yeah that's the site, the full map covers to the entire area, but its all in that same location.

[ChicagoLooper]

@A_HULL-2021 

OK, great. 

Your drawing is using a Mercator projection known 'loosely' as WGS84 Mercator.

<<Be forewarned, other geospatial programs may only give the projection a similar name, not the exact same name. Never ever will it be the exact name. SMH. All programs, however, give it the EPSG code 3857. Unlike world wide UTMs, EPSG 3857 doesn't have any zones. It's not a regional CS, it has world wide coverage and uses unit of Meters.>> 

If you still have the original drawing without changes, try this:

1. MAPCSASSIGN=>In the search box input 3857=>select the result=>Click 'Assign' button (You MUST!! assign a CS if you plan on exporting to another GIS-essy program.)
2. Turn on Bing Hybrid aerial map (Is the aerial imagery consistent with your linework?) 
3. Use MapExport command and export to shapefile (SHP) format. Make your selections for exporting. Make sure to check the box labeled Convert coordinates to: on the Options Tab so you can convert to LL84, aka WGS84 datum, EPSG 4326.

When exporting to shapefile format, you'll need to export each Feature Class separately, meaning, your first export will exporting points, second export you'll export lines, and finally for export you'll export polygons. Make sure to Convert to LL84, EPSG 4326 for each individual export. If you only have one Feature Class, then you can export just that one and ignore the other feature classes.

You may TEST your exported shapefiles by opening them in Google Earth Pro or any other GIS mapping program that accepts shapefile format.

[A_HULL-2021]

The file I have been provided uses OSGB1936.NationalGrid. When I follow the steps provided, the points don't scale correctly.

If I follow your export instructions, I get the following error:
"0 object(s) of 1936 selected, exported in 0 sec(s).
1936 entities were skipped due to failed coordinate transformations.

[Pointdump]

Hi Archie,
"Expected: X = 53.9122, Y = -0.1618
Actual: X = 564555108.8295 Y = 432344676.6551"
I can't get these numbers to work. The X and Y look reversed, and even if the huge coordinates are millimeters, they still don't match. Need more information.
Dave

[A_HULL-2021]

Hi Dave, the top image looks correct, as I have placed the geo-reference on the top right corner of that building. I got them using the ID command to get CAD coordinates, then from looking at the “Geographic” coordinates on the bar on the bottom of the screen. I noticed the plotted points are very far away from the origin, which is more noticeable if I remove the CRS/geo-reference, as the screen zooms out to show the origin and the drawings, which appear as a small blob.

Other points are:

 564552146.4655, 432343333.6304 == 53,9001, -0.2069

564551071.3369, 432346530.5326 == 53.9288, -0.2233

What extra information do you need?

[Pointdump]

Archie,
"564552146.4655,432343333.6304"
These numbers don't belong to any coordinate system that I know of.
Use Command -DWGUNITS to check units. Map 3D is built on top of AutoCAD, but there is no error-checking if the units don't agree.
"1936 entities were skipped due to failed coordinate transformations."
If your drawing units are Millimeters, that would explain.

A Latitude of 53.9122 and Longitude of -0.1618 would be 124 Meters from that building corner, in OSGB1936.NationalGrid.
Dave

[A_HULL-2021]

"""
Command: -DWGUNITS
Drawing units:
1. Inches
2. Feet
3. Millimeters
4. Centimeters
5. Decimeters
6. Meters
Unit for length <6>:
Drawing unit display formats:
1. Scientific
2. Decimal
Linear display format <2>:
Linear display precision <4>:
Scale objects from other drawings upon insert? [Yes/No] <Yes>:
Match INSUNITS to drawing units? [Yes/No] <Yes>:
"""

I've attached a clean .dwg I've been provided

Many thanks

[Pointdump]

Archie,
Thanks for posting your drawing.
Someone has used the command GEOLOCATION on your drawing. That command is intended for Vanilla AutoCAD and usually wrecks a Map 3D drawing. Use command GEOREMOVE, then use MAPCSASSIGN to re-assign EPSG:27700 to your drawing. When you zoom out you'll see how wildly out of the extents of 27700 you are.
How to fix? I don't know. Even scaling by 1/1000 won't be "close enough".
Dave

[A_HULL-2021]

Thanks for taking a look Dave.

I've been tasked with extracting the real world long-lat from the lines in the drawing, so they can be imported into a GIS-type front-end. I'm starting to wonder whether this will be possible with the data I've been provided. I believe the original file was done in Vanilla, I started using Map3D following advice I had seen in other forums. 
Would appreciate any suggestions on how I could try to "fix" the drawings I've been given so that they're exportable without conversion errors.
Much appreciated.
A

[Pointdump]

Archie,
"starting to wonder whether this will be possible with the data I've been provided."
I can't think of any way to fix your drawing. Scaling by 1/1000 still puts it in the ocean.
Dave

[A_HULL-2021]

Hi Dave,
Does this scaling also relate to the "entities were skipped due to failed coordinate transformations." issue?
Thanks

[Pointdump]

Archie,
"entities were skipped due to failed coordinate transformations"
Yes, Map 3D doesn't know what to do with those huge coordinates.
The reason I tried scaling was that the numbers looked more like millimeters than meters.
Dave