How to get accuracy in Drone / UAS Mapping with Pix4D: What You Need to Know

drone mapping isn't always about flying also about walking you got out of good DCP welcome to gm6 drone mapping this is episode 4 in a series we've been asked by the project manager of the construction site that we've been mapping to create an updated contour map the only way to do this accurately is with GCPs this is important and valuable at this stage of the construction project since the contour of the land affects watershed and structural stability as the foundation is built in this episode we're going to cover GCPs contour lines and GIS so let's start with the basics GPS or ground control points are important because they give the project scale and orientation this allows us to make accurate measurements then we'll discuss contour lines and how they relate to drones and construction and finally GIS geographical information system which allows us to analyze the data that we create in pics for D in pics for DS BIM solution there's an option to upload a cad image that you can overlay onto the map I'm going to show you how to create contour lines and overlay them on the map where the CAD file goes first thing I do in the bim desktop is create a project when you import the images the software will read the geo tags and create a file called an exit file that also allows the pictures to be placed in the correct position on the earth after I've uploaded the images I then pick the correct GPS coordinate system for the GCP that have been created the default coordinate system that's used in many cases is called wgs84 world geodetic system 1984 this is important because the GCPs are normally recorded in a different system fortunately fix 4d has dozens to pick from after I pick the correct coordinate system for my GCPs and output files ready to select the parameters I need to process my project I like to create my own template for my projects so in step one I'll leave it at default which is full image resolution step two I'll leave the point cloud at half scale and leave the output files for the point cloud unticked because it takes longer to process and I don't need the point cloud for this project step three in the DSM or the mosaic tab I leave this at default settings next is the additional output tab I don't need the grid DSM but I do want to check the geotag because I want to build my contour lines from the roster DTM file I leave the roster DTM resolution at the default settings of five times the GSD which is ground sampling distance and then I check the box for PDF file I then set my base elevation for my contour spacing and resolution then I'll leave my vertices at 20 that's the number that represents the width of the contour lines click OK after all that's done unpick steps 2 & 3 I first run step 1 then after step 1 is complete I will come back and add my GC piece okay now that step one is complete I'm going to add my GC piece first thing to do is go to the project tab and click on that and then go down to DCP manager you click import GCPs and navigate to wherever your text file is double-click that and then click ok once those populate here in the box we're going to go down to basic editor there's more than one way to add GCPs but this is the way that I like to do it seems to be easier than me anyway so I'll first click on the first DCP at the top this little box on your left are the images where your GCPs should be you may occasionally find a picture that doesn't have your mark in it for your DCP that's ok you just go to the next one you need a minimum of 3 images with the GCP located in order to process that point so I'll go over here and scroll down and click on it and I'll click on the next picture scroll down click on that one and I will just continue to go through here and do this let me do it five to eight times just depends and then you go to the next DCP up here in the top click on it and then do the same thing over and go through my case I'll go through five of them and then when that's done I'll just click OK and you can see that the GCPs are not lined up with the point the way to fix that is go up here to the top again to the process tab click on re optimize and click OK and that should take a few minutes depending on the speed of your computer and then when that's done it should look like this so after they're optimized now they're in the correct location and altitude so that looks good so next you will uncheck step one so we don't redo that one and then tick the box for steps two and three and hit start now steps two and three are done so we'll close ticks for D and open Q gif which is an open-source version of what gif and go up here to the layers tab and add layer and add roster layer from there you'll navigate to your folder where you have your project saved we'll open that then go to DSM ortho extras and DTM and I'll select the TIFF file or this project first thing I like to do is go over here on the left hand side double click to enter the attributes table I'll turn mine down a half way just to change the transparency slider then go to view all the way down to panel and toolbox here you can search for any tools you need so the first thing I need is the contour so I'll double click that brings up your contour box and I need one foot intervals 101 it run and this will take anywhere from a few seconds to minutes depending on your computer speed close this out and I'm going to change my contour colors by clicking on the attribute table on the left hand column there and I'll go to the drop down box to show labels and then label with I want the elevation and then next I'll go to style I want black for contour lines click OK click OK again and you can see the contour lines and they'll populate with the numbers that will show the elevation for each line all right so there you have it there's how you create the contour lines you can see the elevations over here there's there's ways that you can decrease the amount of numbers showing but for now just leave it at that and then one other little tip I like to use is I will go I'll go back into the layers add layer roster layer this time I'll go to DSM ortho and mosaic and then double click on the tiff file in the mosaic and you can see here it shows the actual north of mosaic now you don't see the contour lines you want to be sure to drag the label the name below the contour labels so that it'll show the lines and it will populate again with the elevations then I'll turn off the other label because I don't need that any longer and now what I'll do is go to project save as image then I'll go back to my folder where all of the files are stored for picks for D and save this I will go into my project that I have loaded in pix 4d BIM and right here on the inside you'll see it says CAD overlay so you can click on replace and as you can see I have numerous other files here so I'll click upload go into the file where I save that image hit open and it will upload so then can check the box and as you can see there's the file I don't believe this was the original purpose for this feature but it works quite well so all you have to do at this point is just line it up and make it fit up early and then you're good to go once that's lined up you can save it and share with your point [Music]

Channel: GM6 Drone Mapping

Views: 38,971

Keywords: How to make money with drones, Make money with drones, drones, drone, drone map, 3D Mapping, 3D Mesh, Agisoft, Drone Mapping, Dronedeploy, Fixed wing drones, GIS, Pix4D, UAS, UAV, www.guardmy6.com, guardmy6, GM6 Solutions, drone companies, drone images, US Map, Photogrammetry software

Id: R1vN6v_d2Fk

Length: 12min 11sec (731 seconds)

Published: Sat Aug 19 2017