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mapdist command

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Message 1 of 11
dchristensen
916 Views, 10 Replies

mapdist command

When using the mapdist command the measurement is different from the actual line that I create. The map coordinates and the maptrack coordinates match. When I open a older drawing there is not an issue. Did I somehow change the origin of my template.

Any suggestions thanks

 

Here is sample from the command line

 

Command: _mapdist
Specify first point:
Specify second point:
Distance = 12.7513 (Foot)
Azimuth = 38 degrees (forward), 218 degrees (reverse)
Delta X = 15.0000, Delta Y = -0.0381

10 REPLIES 10
Message 2 of 11

DIST calculates the distance between two points in space.
MAPDIST calculates the distance as measured on the earth's surface.

If no coordinate system is assigned to your drawing, DIST and MAPDIST will return the same values. If you assign a coordinate system based on a map projection for your DWG, then you will of course see a difference between the two measurements.

Here is an example. I assigned HARN/WO.OR-S to my drawing, drew a polyline, and measured the distance of that line using DIST, and then MAPDIST. Here are my results:

DIST
Distance = 7.8132

MAPDIST
Distance = 7.7772

I hope this makes sense Smiley Very Happy


Phil Borycens
Message 3 of 11

When drawing lines there is a difference between the line drawn and the mapdist measurement. Is there a way to draw the line so both distances are equal? David Christensen CAD/GIS Technician Marquette Board of Light and Power 2200 Wright St. Marquette, MI 49855 Office: (906) 228-0326 Cell: (906) 361-8237 Fax: (906) 228-0305
Message 4 of 11

I am using AutoCAD maps 3d using the geo function to insert a map in the background.

 

I inserted two geographic points with the following locations:

 

35.7137N, 14.6553E

 

35.7730N, 14.7274E

 

I am using the mapdist function to find the geodetic distance between these two waypoints. The mapdist function returns 11395.8432m, whereas the true distance is 9260m.

 

Can you please give me an insight in this problem??

Tags (1)
Message 5 of 11

To add to my previous post, I am using the WORLD MERACTOR -WGS 84 as the GIS co-ordinate system.

 

Message 6 of 11

Hi Matthew:

 

Thank you for your posts, and especially for letting us know which coordinate system you are using. Rest assured that you are not going crazy, nor are you using the program wrong...

 

There is a known issue with MAPDIST in the WGS84 datum; distances are not calculated correctly. This is being tracked internally as 1206299. Thank you for bringing it back to our attention.


Phil Borycens
Message 7 of 11

Thanks!

Sent from my iPhone
Message 8 of 11
fcernst
in reply to: phil_borycens

DIST
Distance = 7.8132

MAPDIST
Distance = 7.7772

 

I hope this makes sense :smileyvery-happy:

 

 


No, it doesn't make sense. Why is the geodetic distance shorter?



Fred Ernst, PE
C3D 2024
Ernst Engineering
www.ernstengineering.com
Message 9 of 11


@phil_borycens wrote:

Here is an example. I assigned HARN/WO.OR-S to my drawing, drew a polyline, and measured the distance of that line using DIST, and then MAPDIST. Here are my results:

DIST
Distance = 7.8132

MAPDIST
Distance = 7.7772

 


I also noticed today that the distances between points from MAPDIST are less than the distances between the same points from DIST:

  Command: DIST
  Specify first point:
  Specify second point or [Multiple points]:
  Distance = 1708.56, Angle in XY Plane = 358.077, Angle from XY Plane = 0.000
  Delta X = 1707.60, Delta Y = -57.33, Delta Z = 0.00
  Command: MAPDIST
  Specify first point:
  Specify second point:
  Distance = 1707.88 (Meter)
  Azimuth = 89.994 degrees (forward), 270.006 degrees (reverse)
  Delta X = 1707.60, Delta Y = -57.33

I inserted the points by the values of latitudes and longitudes in MAPTRACKCS or with the 'LL. In dwg assigned UTM84-...N.
Is there any explanation for this?

 


-- Alexander, private person, pacifist, english only with translator 🙂 --

Object-modeling _ odclass-odedit.com _ Help

Message 10 of 11
Gary_Braun
in reply to: fcernst

Because he's using a projected coordinate system and drawing on the grid, so the grid distances are shorter than ground.

Message 11 of 11

In options MAPTRACKCS there are grid settings. But I only saw them there.
Is the grid also used in MAPDIST? If so, with what step, where is it regulated?
All this seems strange to me...

 


-- Alexander, private person, pacifist, english only with translator 🙂 --

Object-modeling _ odclass-odedit.com _ Help

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