survey

Yes It has been done.

Areal photography are however distorted and will be inaccurate if precautionary measures are not followed.

After some cheap measures it was between 95% - 100% against surveyed areas, which should be sufficient for agriculture purposes.

Improving the accuracy was expensive.

When we started in 1976 we had to use a digitizer but with modern screens mouse digitizing on digital photos is sufficient.

Hello Guest,

Of course it is.

All earlier Topographical maps were made using aerial photographs, viewed through a stereoscopic set of lenses.

Expanding on Hendrik points above, if you do not have properly calibrated height of the photographing plane, and optics details of the camera lenses, you will need to ensure that you have measurable items or markings across the landscape in a grid pattern, to be able to calculate correctly.

These can be rods of equal length, fenceposts in the ground at regular intervals, houses and barns of known dimensions, and the like.

Depending on location, you could use Google Earth Download if the local area detail is fine enough, because the viewing height is variable, plus you are able to slew the view from all directions, and also the viewing height is selectable by you, and advised at all times.

If you have not used Google Earth, Download at above link, Instal to your Computer, you will need a fast Internet connection ADSL/Cable to use Google Earth - have fun.

An alternative is to use Flashearth.

Some 50 years ago, we used black & White aerial photos to do initial surveys for Power Pylon transmission lines, over hundreds of miles, with the fine detail being on-foot surveying with theodolite etc.

Hope that assists you.

Kind Regards....

Please research Photogrammetry.

http://www.asprs.org/

http://www.photomodeler.com/index.htm

milo

One ancient photographic method for measuring irregular areas without planimetric software is:

• make a photo using a vertically oriented camera.
• make a photo of a known area using the same camera and orientation
• print, using appropriate enlargements
• carefully cut out the irregular and the known areas
• weigh both
• calculate weight ratio
• use appropriate multiplication scaling to obtain area.

A more practical answer to your question

In the past we used aerial photos taken from a light aeroplane and with all the necessary information at hand.

One could put a stereo pair on a stereo plotter and get detailed plans. In my time it took about half a day just do the setup.

We however sometimes used more crude methods with acceptable results.

Lately one can get these photos in digital format and referenced. These can then be used in a GIS or CAD system.

Measurements can be done.

This was exported out of ARCVIEW 3.2 from ESRI.

They have Arcexplorer for free.

I once imagined being able to take a picture of a room slated for renovation and recieve back with the picture measurements of the room along with level and out of level plumb information so as to obviate the need for laying on the level and pulling out the tape & so on.

At the time I imagined the device dedicated machine, camera, I had a fine set of input and outputs, but now am fuzzy on what I had imagined.

At anyrate you have reminded me of the project, which has been explained as done and doable.

The name of the most current system of machine and software would be good to know, as well as interior and exterior or landscape and interior applications.

Aerial photography is frequently used for just this purpose. I understand that it is also used in the minerals and coal handling industries for defining the size and height of storage piles for cost accounting purposes.

Right on this!

At the coke plant in Lorain, we would outline the edges of coal piles with burnt lime. (white powder like chalk)

The angle of repose of coal was an accounting standard. My lab would run triplicate samples for bulk density of the coal in each pile. My guys loved that overtime.

The plane would fly over at Noon local time. and they had a calibrated standard on the ground.

One superintentent at another coke plant was fired on the basis of this, as they charged him with huge loss of coal (shrinkage). the new superintendent reviewed the numbers, saw that the error was the use of the wrong bulk density for the calculation (the ACCOUNTANTS used the density for coke, not coal, resulting in huge writedown. But they didn't want top pay the lab guys overtime to sample each pile, and just used the bulk density number that they as accountants"knew"- just happened to be for the wrong product.)

New superintendent was lionized for his victory. Old one was a goat for not understanding the math.

Wish I had kept those pictures.

milo

This is a very simple problem. I do this normaly at about 1:5000 relative precision but much higher is posible. I would explain if the thread is interested. There are many ways

ASPRS has lots of other photogrammetrists

An easy way is to export the aerial image from Google Earth or Google Maps into AutoCAD.

Use a screen dump or other method to export image including scale. Import into AutoCAD as an image.

Scale image until the scale on the photo matches the "real" scale in AutoCAD. Put photo to the back in the drawing order.

Digitize a closed polyline directly over the photo. Set line color to a contrasting color for visibility.

Pick line to read area directly.

Viola!

Geospatial http://tce.geospatial-solutions.com/gsstce has a mapping process and software that will allow you to make reasonably good measurements from aireal photos, pick points of interest and calculate the distance between the points. I believe they are using fractals but don't quote me. I've seen the package demonstrated and have used a trial version to show my town government how a forever wild area was laid out. It's a nice package, check it out.

Just like the other guys have already mentioned, yes, it's entirely possible. I used various scales of aerial photos for forest mensuration when I was in collage, and later in the industry of land and road surveying.

If you want to really have some fun, take a room that needs to have a dimension drawing for court purposes, and be accurate within a 16/th of an inch. Bull, you think? No. It is doable. All you have to do is find a common object like a pencil, or a telephone, maybe a light switch or plug-in for the wall outlets, something common, locate the dimension and apply it scale accordingly, and you will have your area come together. I used to do this for a County Court when I worked as a surveyor's assistant quite often. Had some tense times.

Have a good one.

Yes definitely.....But it will be an approximate area.....it will require an scale factor............

For most agricultural applications, it can be done reasonably straight forward by importing the modern high resolution aerials into ACAD, if you know the boundaries and can identify them on the photo. (We use google earth a lot for good photos for agricultural applications).However, it is not very precise for small scale and there are large scale errors that increase, so it is good for the 10 acre to 1000 acre scale usually. You draw in the boundaries in ACAD and ACAD will have the area calculated for the bounded area (in the units used). Keep in mind you must properly import the photo to the right scale. You can use ACAD to bound multiple parcels and determine the area of each readily. (it is probably a bit complicated to do for a simple square or rectangular parcel). An even better method is just to obtain the parcels legal description from the local authority.

yes sure it is possible to calculate the area by using the photographs.

If we know the pixel size or pixel dimension of the photograph it is possible.

Consider a Aerial photograph. If we know the pixel dimension of this photograph then

using photogrammetric techniques using the photoscale and scanning resolution of the image the area can be calculated.

Further you can find some information at this link..

Whether its possible to calculate an area by using the photograph of that area.

http://www.sblgis.com/photogrammetry_services.aspx

http://www.sblgis.com/geospatial-case_study.aspx

You can determine a scale from any known structure shown in the photograph that is hopefully much larger than the one you are analyzing. thus if you know that from intersection CL to CL the length of a road shown in a aerial photo, you can determine a scale from which to base measurements on the photo.