topic Re: Tracing site plans from google images in AutoCAD Forum

Tracing site plans from google images

Anonymous — Wed, 05 Jun 2019 19:42:14 GMT

I'm looking for the best way to trace over a google map or google earth site plan image for Autocad. This doesnt need to be extremely accurate just a basic outline. What i currently do is look up the address on google maps or google earth and try to get it to be as flat and straight of a view as i can. This is the problem with google maps or google earth. the view is not necessarily looking down directly at the site its somewhat at an angle. I then bring it into Autocad and try to scale it to what i think it should be. What do most people do? Is there a better more accurate way? I'm only running version 2016 so if there is anything in 2018 or beyond i probably wont be able to do it. I thought that they had made some geographical enhancements but i'm not sure ill be able to use anything past 2016

Re: Tracing site plans from google images

Alfred.NESWADBA — Wed, 05 Jun 2019 19:54:55 GMT

Hi,

does it have to be GoogleMaps or would BingMaps also work for you?
If yes then please start command _GEOGRAPHICLOCATION ==> _MAP ==> and continue with that dialog (>>>more details<<<).

In case you have Map3D or Civil3D you can first use command _MAPCSASSIGN to assign your preferred geographic coordinate system and then command _GEOMAP which brings in the BingMaps images already in the correct location.

- alfred -

Re: Tracing site plans from google images

Anonymous — Wed, 05 Jun 2019 20:06:52 GMT

Can you make bing maps have a 2d type view? Thats why i typically use google maps so that i can make it as 2d flat plan view as i can. We only run vanilla autocad 2016 so i dont have access to anything other than that.i just need to draw the outline of the site showing striping, resataraunt drive thru areas, etc.

Re: Tracing site plans from google images

Anonymous — Wed, 05 Jun 2019 20:08:45 GMT

here is a sample

Re: Tracing site plans from google images

Alfred.NESWADBA — Wed, 05 Jun 2019 20:09:26 GMT

Hi,

>> Can you make bing maps have a 2d type view?

Have you tried it? It only shows the map in 2D.

>> We only run vanilla autocad 2016

Then please use my first suggestion.

- alfred -

Re: Tracing site plans from google images

Anonymous — Wed, 05 Jun 2019 20:16:56 GMT

Doesnt seem to zoom very close. i usually know the size of the building and i assume a certain size of sidewalks or parking stalls and i try to scale off of that

Re: Tracing site plans from google images

Alfred.NESWADBA — Wed, 05 Jun 2019 21:00:03 GMT

Hi,

>> Doesnt seem to zoom very close

It zooms as close as BingMaps allows to zoom (same as in BingMaps in Internet browser).

>> i usually know the size of the building and i assume a

>> certain size of sidewalks or parking stalls and i try to

>> scale off of that

In the GEOGRAPHICLOCATION dialog you were asked to select a coordinate system + the units you are using. Then (if these values are entered correct) you get the exact size of the objects displayed in AutoCAD (well, accuracy is limeted).

- alfred -

Re: Tracing site plans from google images

pendean — Wed, 05 Jun 2019 21:20:33 GMT

>>>...What do most people do? Is there a better more accurate way? ...<<<
Go out there, survey the site, then draw it up.

>>>...doesnt need to be extremely accurate just a basic outline...<<<

Then just "trace over it" and call it a day: you probably would be done by now considering the time you spent.

HTH

Re: Tracing site plans from google images

Anonymous — Wed, 05 Jun 2019 21:49:22 GMT

@pendean wrote:
>>>...What do most people do? Is there a better more accurate way? ...<<<
Go out there, survey the site, then draw it up.

If i could do that i wouldn't be using google to try and get something at least somewhat accurate. I'm not trying to get down to the inch, but i cant just draw anything up.

>>>...doesnt need to be extremely accurate just a basic outline...<<<

Then just "trace over it" and call it a day: you probably would be done by now considering the time you spent.

I am tracing over it, but i was having trouble getting it to come out good enough. I know that the building is roughly, 30'-0" wide x 76'-0" long plus the overhang which is what google shows (the overhang). The problem with google is its not like its directly over the site. its looking down at an angle.
HTH

Re: Tracing site plans from google images

TerryDotson — Wed, 05 Jun 2019 22:07:42 GMT

The problem with google is its not like its directly over the site. its looking down at an angle.

That is going to appear on even the highest quality imagery. The plane doesn't snap photos as frequently as desired and the /|\ angle problem is going to happen. Trace it, make a block of it and scale it with different XY scales, then explode. If you want accuracy, enlist the services of a surveyor!

Re: Tracing site plans from google images

scot-65 — Wed, 05 Jun 2019 22:42:59 GMT

Non-geomap method:

Use a GIMS map instead.
Most major cities have this on the web for free access.
Be aware that silverlight is not friendly to all other browsers except IE.
Show the boundaries with distances as well as building outlines
(buildings are usually in a different color only - no distances and
sometimes not accurate and will disappear if zoomed in too close).
Show other layers as required (street center line, etc.).
Keep aerial view off (my preference).
Take a screen capture [Print Screen] on the keyboard.
Paste in your favorite image editor, crop image as required and
save as a JPG.

Now,
a) Open image in your favorite web browser and right-click "Copy"
on the image itself. Close browser.
b) Insert image - command PASTESPEC into a blank DWG drawing.
Accept the defaults if it is a JPG. Scale is 1.0.
c) Find a logical pin and move the image using the pin as a
reference point to 0,0.
d) Save as "Underlay01.DWG". Close this drawing.
e) Open the destination drawing and with your favorite file manager,
drag-drop the underlay drawing into the destination drawing (unexploded).
f) Rotate the underlay block as required.
g) Draw at least 2 circles (shares the same center point) which
represent distances of at least 2 lengths from the pin (x-distance
and y-distance). The greater the distance, the more accurate it will be.
h) Grip-edit the underlay block and move to the center point
of the 2 circles. Draworder to back the underlay block.
i) Scale the underlay block as required (start with 1200 arch.) using the
properties pane until the circles crosses exactly to the other end of
the known line lengths. Image may be distorted - x- and y-scale
might be slightly different - again, use the properties pane.
AutoCAD might be sluggish during this fine tuning - live with it.
If the underlay block is set to be uniform scale, BEDIT the underlay
and in the properties pane turn off the uniform scaling. BCLOSE.
j) Trace on top.

This same method can be used for a PDF underlay.

???

Re: Tracing site plans from google images

pendean — Thu, 06 Jun 2019 12:49:38 GMT

Satellites take pictures at angles since our planet is not flat, and they do net move around just to get the perfect above picture of every site of every building on the planet, in case you never thought about it before today.

Either use what you have (good enough per your words), or go out there and survey it: there is no automagical tool that is going to work here.

Good luck.

Re: Tracing site plans from google images

leeminardi — Thu, 06 Jun 2019 15:30:54 GMT

It's not clear how you are bring the shape from Google Earth into AutoCAD.

If you create a polygon shape in GE you can copy/paste it into Notepad and easily extract the latitude and longitude in decimal degrees. From here I would copy paste the coordinates into Excel. To get the correct aspect ratio of the shape you would need to scale the shape in x by by cos(latitude). One you have the correct aspect ratio you can scale the shape using a know dimension to determine the scale factor.

For example, in the following I took a GE polygon that I measure in GE to be 1945' east/west by 1845' north/south. Column F is the difference in degrees. The 1845 in cell G3 was one of the known dimensions. The 363700.8 (cell I3) is the scale factor G3/F3. The result of 1948.774 is close to the measured distance of 1945 given the error in using the GE measure tool.

Re: Tracing site plans from google images

Anonymous — Thu, 06 Jun 2019 15:52:32 GMT

@leeminardi wrote:
It's not clear how you are bring the shape from Google Earth into AutoCAD.

Basically, i do a screen shot either from google maps or google earth & then attach the image like an xref. i find that i have an easier time working with it that way than if i if i use paste special

If you create a polygon shape in GE you can copy/paste it into Notepad and easily extract the latitude and longitude in decimal degrees. From here I would copy paste the coordinates into Excel. To get the correct aspect ratio of the shape you would need to scale the shape in x by by cos(latitude). One you have the correct aspect ratio you can scale the shape using a know dimension to determine the scale factor.

For example, in the following I took a GE polygon that I measure in GE to be 1945' east/west by 1845' north/south. Column F is the difference in degrees. The 1845 in cell G3 was one of the known dimensions. The 363700.8 (cell I3) is the scale factor G3/F3. The result of 1948.774 is close to the measured distance of 1945 given the error in using the GE measure tool.

Re: Tracing site plans from google images

caterina.damico — Fri, 16 Oct 2020 23:28:10 GMT

In order to make it from above juin google earth just go on View then reset then inclination and compass!