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Konstantin
Guest
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 Posted:
Fri Dec 03, 2004 10:32 pm Post subject:
Inputting Points Using Lattitude and Longitude |
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I have to input several points into an Autocad drawing. The coordinates for these points are given in lattitude and longitude. Is there any simple way of entering these or converting these points to X,Y coordinates?
The area is rather small, and it does not have to be very accurate, so the curvature of the earth can be ignored.
Thank you
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Jason Rhymes
Guest
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| Posted:
Fri Dec 03, 2004 10:43 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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| You have an example? or a excel table? |
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Allen Jessup
Guest
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| Posted:
Fri Dec 03, 2004 11:01 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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If your just using vanilla AutoCAD I'd suggest Googling up CORPSCON. Its a
free program compiled from stuff written by the Corps of Engineers. It will
process a batch file containing Lat-Long's. You can select which State Plane
system you want. If that doesn't matter just pick one at random. That will
give you X,Y that you can either enter or bring in using a script file.
Allen
"Konstantin" <nospam@address.withheld> wrote in message
news:6574072.1102095162334.JavaMail.jive@jiveforum1.autodesk.com...
| Quote: | I have to input several points into an Autocad drawing. The coordinates
for these points are given in lattitude and longitude. Is there any simple |
way of entering these or converting these points to X,Y coordinates?
| Quote: |
The area is rather small, and it does not have to be very accurate, so the
curvature of the earth can be ignored.
Thank you |
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ekubaskie
Guest
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| Posted:
Fri Dec 03, 2004 11:51 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Are you running vanilla AutoCAD?
With AutoCAD Map it's pretty easy - plot the points in one drawing in lat-long coordinates, save and attach that drawing from a new one in your desired coordinate system, and query the data. |
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Konstantin
Guest
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| Posted:
Mon Dec 06, 2004 8:43 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Ekubaskie
I do not know what "Vanilla Autocad" is so I probably do not have it. I have standard Autocad and Autocad map.
Your suggestion about entering the points in latitude-longitude coordinates is exactly what I want to do, but I do not know how to enter them.
I have read the help files and figured out how to query the data into a new drawing as you suggested. But I do not know how to begin by inputting the points in latitude-longitude coordinates.
Thank you for your help. |
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Lisa
Guest
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| Posted:
Mon Dec 06, 2004 10:38 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Its just like drawing a line without picking the points. You need to set
your units (Angle) to degree/min seconds. the draw like the following
example:
if you need a line that is 135 feet at 62d51'35"E
you would type it like this:
pick any point to start,
@135'<62d51'35"E
you can start your point at 0,0 or any point. just remember to have the @
symbol
"Konstantin" <nospam@address.withheld> wrote in message
news:19387540.1102347852221.JavaMail.jive@jiveforum2.autodesk.com...
| Quote: | Ekubaskie
I do not know what "Vanilla Autocad" is so I probably do not have it. I
have standard Autocad and Autocad map.
Your suggestion about entering the points in latitude-longitude
coordinates is exactly what I want to do, but I do not know how to enter
them.
I have read the help files and figured out how to query the data into a
new drawing as you suggested. But I do not know how to begin by inputting
the points in latitude-longitude coordinates.
Thank you for your help. |
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ekubaskie
Guest
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| Posted:
Tue Dec 07, 2004 4:04 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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How the name of one of the most sensuous flavors/scents in existence came to mean "ordinary" or "plain", I just don't know - but that is what the expression means; i.e. Standard AutoCAD.
You're almost there. The correct lat/long system depends on the source of your points. If they come from GPS, use WGS84 datum, Latitude-Longitude; Degrees.
Latitude is X, Longitude is Y, with West Longitude negative. Both need to be input as decimal degrees, not as degrees-minutes-seconds.
Draw your lines or points using the decimal lat-long as X-Y. I find points difficult to identify later, so I usually to text objects (very small, height about 0.001) with their insertion points at the lat-long point, and the actual text is for identity; i.e., "P1" for "Point 1". |
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Doug Broad
Guest
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| Posted:
Tue Dec 07, 2004 9:26 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Konstantin,
Take care. All the advice available on the NG's is not necessarily
knowledgable. Latitude and Longitude as you probably know are
in degrees and cannot be entered as x and y coordinates. Each
degree of latitude is approximately 60 nautical miles (69 statute miles).
It varies slightly due to the curvature of the earth (as you know) and
near the north pole a degree of latitude is 69.407 miles and at the
equator it is 68.703 statute miles.
A degree of longitude is widest at the equator at 69.172 miles
(111.321) and gradually shrinks to zero at the poles.
At 40° north or south the distance between a degree of longitude
is 53 miles (85 km). To determine the distance between degrees
of longitude at a particular latitude, you need to use the cosine
function.
Length of 1 degree of Longitude = cosine (latitude) * length of degree (miles) at equator
There are calculators available that use approximate calculations (fixed latitude
dimension) to determine the distance between two points.
These distances are also only relevant at mean sea level.
Example:
http://www.wcrl.ars.usda.gov/cec/java/lat-long.htm
If you want to enter points as coordinates on the earth you could treat
the points as spherical coordinates from the center of the earth. The mean
radius of the earth is 3959 miles. You could enter the points directly as
3959<longitude<latitude
That format demonstrates spherical coordinates. After drawing the points, you
should be able to measure the distances and choose a view that is normal to a
plane containing 3 of the points. Then you could use projection to flatten them
to X, Y values.
Regards,
Doug
"Konstantin" <nospam@address.withheld> wrote in message news:19387540.1102347852221.JavaMail.jive@jiveforum2.autodesk.com...
| Quote: | Ekubaskie
I do not know what "Vanilla Autocad" is so I probably do not have it. I have standard Autocad and Autocad map.
Your suggestion about entering the points in latitude-longitude coordinates is exactly what I want to do, but I do not know how to
enter them.
I have read the help files and figured out how to query the data into a new drawing as you suggested. But I do not know how to
begin by inputting the points in latitude-longitude coordinates.
Thank you for your help. |
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Allen Jessup
Guest
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| Posted:
Wed Dec 08, 2004 12:21 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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I would suggest converting the Lat Long to a parallel plane coordinate
system. I use Corpscon...
http://crunch.tec.army.mil/software/corpscon/corpscon.html
Then you can enter the points as X,Y.
Which system to use depends on what your trying to do with the data.
Allen
"Doug Broad" <dbroad@earthlink.net> wrote in message
news:41b5310f_3@newsprd01...
| Quote: | Konstantin,
Take care. All the advice available on the NG's is not necessarily
knowledgable. Latitude and Longitude as you probably know are
in degrees and cannot be entered as x and y coordinates. Each
degree of latitude is approximately 60 nautical miles (69 statute miles).
It varies slightly due to the curvature of the earth (as you know) and
near the north pole a degree of latitude is 69.407 miles and at the
equator it is 68.703 statute miles.
A degree of longitude is widest at the equator at 69.172 miles
(111.321) and gradually shrinks to zero at the poles.
At 40° north or south the distance between a degree of longitude
is 53 miles (85 km). To determine the distance between degrees
of longitude at a particular latitude, you need to use the cosine
function.
Length of 1 degree of Longitude = cosine (latitude) * length of degree
(miles) at equator
There are calculators available that use approximate calculations (fixed
latitude
dimension) to determine the distance between two points.
These distances are also only relevant at mean sea level.
Example:
http://www.wcrl.ars.usda.gov/cec/java/lat-long.htm
If you want to enter points as coordinates on the earth you could treat
the points as spherical coordinates from the center of the earth. The
mean
radius of the earth is 3959 miles. You could enter the points directly as
3959<longitude<latitude
That format demonstrates spherical coordinates. After drawing the points,
you
should be able to measure the distances and choose a view that is normal
to a
plane containing 3 of the points. Then you could use projection to
flatten them
to X, Y values.
Regards,
Doug
"Konstantin" <nospam@address.withheld> wrote in message
news:19387540.1102347852221.JavaMail.jive@jiveforum2.autodesk.com...
Ekubaskie
I do not know what "Vanilla Autocad" is so I probably do not have it. I
have standard Autocad and Autocad map.
Your suggestion about entering the points in latitude-longitude
coordinates is exactly what I want to do, but I do not know how to
enter them.
I have read the help files and figured out how to query the data into a
new drawing as you suggested. But I do not know how to
begin by inputting the points in latitude-longitude coordinates.
Thank you for your help.
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Doug Broad
Guest
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| Posted:
Wed Dec 08, 2004 1:26 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Thanks for the link Allen.
"Allen Jessup" <jessupa@co.rockland.ny.us> wrote in message news:41b60246$1_2@newsprd01...
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ekubaskie
Guest
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| Posted:
Wed Dec 08, 2004 2:35 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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AutoDesk desighned the LatLong coordinate systems in Map, LDT, and Civil 3D to perform just as I described. Certainly any linework looks massively distorted if you view the latlong drawing, but that is NOT relevant to the question at hand.
What IS relevant is the result, and I have used the method many times to bring GPS data into drawings. Known points fall onto their State Plane or UTM coordinates quite within the GPS equipment's accuracy.
I have also used it to bring in boundary lines for USGS quads and then matched the rasters and had the township & section lines and streets line right up with GIS and CAD mapping. (USGS world files, at least for my area, are not accurate to enough significant digits for accurate placement.) |
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Allen Jessup
Guest
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| Posted:
Thu Dec 09, 2004 8:39 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Yes. Your correct. I was only offering an alternative. This will also work.
I don't view having choices on how to accomplish a task as a bad thing.
"quite within the GPS equipment's accuracy" Which GPS equipment?
"ekubaskie" <nospam@address.withheld> wrote in message
news:21632555.1102455376376.JavaMail.jive@jiveforum2.autodesk.com...
| Quote: | AutoDesk desighned the LatLong coordinate systems in Map, LDT, and Civil
3D to perform just as I described. Certainly any linework looks massively |
distorted if you view the latlong drawing, but that is NOT relevant to the
question at hand.
| Quote: |
What IS relevant is the result, and I have used the method many times to
bring GPS data into drawings. Known points fall onto their State Plane or |
UTM coordinates quite within the GPS equipment's accuracy.
| Quote: |
I have also used it to bring in boundary lines for USGS quads and then
matched the rasters and had the township & section lines and streets line |
right up with GIS and CAD mapping. (USGS world files, at least for my area,
are not accurate to enough significant digits for accurate placement.) |
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ekubaskie
Guest
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| Posted:
Fri Dec 10, 2004 1:56 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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| In a way, we were both suggesting the same thing, considering that the LatLong coordinate systems in Map ARE parallel plane coordinate systems. |
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Konstantin
Guest
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| Posted:
Fri Dec 10, 2004 9:56 pm Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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| Thank you for all of your help. Ekubaskie, I have it solved using your method. Thank you also Doug Broad. My boss, although a nice guy, is not the engineering type. He just "knew" there must be an easy way to enter latitude-longitude into Autocad. After I printed your message and let him read it, he now believes me that it is no simple thing. |
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Doug Broad
Guest
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| Posted:
Sat Dec 11, 2004 3:20 am Post subject:
Re: Inputting Points Using Lattitude and Longitude |
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Glad to help. Somehow I missed the fact that you had AutoCAD Map.
If Map weren't available, it seems like it would be a relatively simple
task to write an input program to convert coordinates from lat,long to
x,y.
"Konstantin" <nospam@address.withheld> wrote in message news:24246746.1102697806702.JavaMail.jive@jiveforum2.autodesk.com...
| Quote: | Thank you for all of your help. Ekubaskie, I have it solved using your method. Thank you also Doug Broad. My boss, although a nice
guy, is not the engineering type. He just "knew" there must be an easy way to enter latitude-longitude into Autocad. After I
printed your message and let him read it, he now believes me that it is no simple thing. |
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