Topographic DTM maps

[R.Cowan]

I have a customer requesting a topographic map of a 40 acre site. I'm planning on capturing the data with my Mavic 3E. Survey grade accuracy is not needed. A couple of questions. Will RTK or GCP's be needed? Also looking for recommendations for a map processing provider with pay as you go option. Any input will be greatly appreciated.

 

[AMann]

There are many different products where you pay as you go to create orthophoto images and topographic maps. The logistics of the project are really important.

What type of land is it, are there a lot of hills, are there trees, or other discernible landmarks for image processing to be able to find matching points? If not, or if they’re very tall trees, you may need ground control points or RTK to help out. If you are going for any accuracy, these will help but I wouldn’t call it an orthophoto without using either of them because you can’t guarantee that the scale will be the same in any direction on the orthophoto and these errors will be compounded on the topographic map produced from them.

So if your customer wants you to use the images for producing a topographic map, I would certainly go with RTK and/or using numerous GCP’s.

 

[R.Cowan]

Thanks AMan for your input. I haven't seen the property yet, but it is 50 miles SW of Houston near a major river. Relatively flat land. It does have trees and vegetation. I will probably visit with my customer to determine if this is just a one time mission or if others will be needed. I need to justify the financial investment for RTK module and RTK network service in Texas which unfortunately isn't free.