What is a densified point cloud?
The densified point cloud is a set of 3D points that reconstruct the model. The X,Y,Z position and the color information is stored for each point of the densified point cloud.
The densified point cloud is computed based on the automatic tie points (ATPs) of step 1. Initial Processing and it provides a very accurate background for distance, surface and volume measurements.
What is a 3D textured mesh?
The 3D textured mesh is a representation of the shape of the model that consists of vertices, edges, faces and the texture from the images that is projected on it.
It is useful to present and visualize the model, share it and upload it to online platforms such as Sketchfab. It is intended to look nice more than to be accurate, so it is not recommended to use it for measurements.
What is an LOD mesh?
The LOD (Level Of Details) mesh is a representation of the 3D textured mesh that contains multiple levels of detail, decreasing the complexity of the model as it is divided into more levels.
The LOD mesh is useful for visualization on the web and from different types of devices, such as desktop PCs, tablets, smartphones, when fast loading is needed. It is the ideal output for smooth and efficient navigation on online viewers.
For step-by-step instructions about how to export the LOD mesh: How to export the Triangle Mesh .
What is a polyline?
A polyline is a continuous line composed of one or more sub-lines. It is created by specifying the vertices of each line.
Pix4D gives the ability to draw 3D polylines, where each vertex has three coordinates. Polylines are typically used to measure distances in the model.
For step-by-step instructions about how to draw a new polyline with the rayCloud: 202560309.
For more information about projected 2D length and terrain 3D length of polylines: Projected 2D length and terrain 3D length of polylines.
What is an orthomosaic?
The orthomosaic is a 2D map. Each point contains X, Y, and color information. The orthomosaic has a uniform scale and can be used for 2D measurements (distance, surface). It corrects the following problems of the input images:
- The perspective of the camera.
- Different scale based on the distance that each point of the object/ground has from the camera.
The orthomosaic generation is different from photo stitching. For more information: Photo stitching vs orthomosaic generation.
What is a reflectance map?
The reflectance map is mainly used when the input is multispectral/thermal imagery. For more information about the reflectance map vs orthomosaic: Reflectance map vs orthomosaic.
For each band, Pix4D produces one reflectance map. The goal is to properly assess the reflectance for a particular feature based on the pixel value in the images. This pixel value is influenced by many factors, including but not limited to:
- Incoming light.
- ISO.
- Aperture.
- Shutter speed.
- Sensor response and optical system.
- Vignetting.
Pix4Dmapper, therefore, uses the camera positions and the reconstructed model to take these different factors into account and produce an accurate reflectance map. To obtain representative results, it is important to have the right equipment. For Pix4D's recommendations concerning camera requirements: Camera Requirements for Precision Agriculture.
What is a DSM?
The digital surface model (DSM) is a 2.5 D model of the mapped area. It can be exported as two different types of files:
- Raster GeoTIFF.
- Point cloud (.xyz, .las, .laz).
Each pixel of the raster geotiff file and each point of the point cloud contain (X,Y,Z) information. They do not contain color information.
For each (X,Y) position, the DSM has only 1 Z value (the altitude of the highest point for this (X,Y) position). This is why it is considered to be a 2.5D model.
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| House - Side view | House - Top view - DSM |
For more information about how to visualize the raster DSM file: How to visualize the GeoTIFF DSM File.
What is a DTM?
The digital terrain model (DTM) is a 2.5 D model of the mapped area after filtering out the objects, like buildings. It can be exported in GeoTIFF raster file format.
Each pixel of the raster file contains (X,Y,Z) information but they do not contain color information.
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| DTM of the city center of Lausanne | DSM of the city center of Lausanne |
What is an index map?
Pix4D generates several well-known indices such as NDVI as well as custom indices. For more information: How to work with Indices - Formulas in the Index Calculator.
Each index is associated with an index map. For each pixel on this map, the value of the pixel is derived from the associated reflectance maps.
- Pixel value in the red reflectance map: 0.4.
- Pixel value in the NIR reflectance map: 0.6.
- Pixel value in the green reflectance map: 0.1.
I want to import a point cloud on the cloud, but there are 4 files (part 1 to 4). But when I am on the cloud, there is only the option to upload one part, so the project is 1/4 on the 3D, is there a way to import the 4 part ??
Hi Dominic, to merge the point cloud files that have been generated locally, check this other Support article https://support.pix4d.com/hc/en-us/articles/206364863-How-to-merge-the-Tiles-of-the-Point-Cloud
orthomosaic not working
Berry,
We would need more details to help. Can you describe what is happening? Are you getting any error? A screenshot would be good to have.
Hello, how can I separate orthomosaic into pieces or export it to different files (after transformation I have file that is about 6gb), so I can upload them to CAD program separately?
Hi, It seems you are having issues importing a big tiff file to CAD. You can have a look here: https://community.pix4d.com/t/very-large-pix4d-orthomosaic-not-importing-in-autodesk-civil-3d/7476/2. The smaller tiles should be automatically generated in every project. I would recommend doublechecking the …\3_dsm_ortho\2_mosaic\tiles 1 folder and loading each individual tile in AutoCAD.
Thanks a lot, have a nice day
Is there a way to clean a 3D roof by modifying the point could on the desktop to be able to measure what is under a roof ? Thank you.
Hi Dominic,
Pix4Dmapper provides an editing tool, which you can use to improve the point cloud, remove noise or reassign point cloud to different classes. More details can be found in this article: https://support.pix4d.com/hc/en-us/articles/202560499-How-to-edit-the-point-cloud-in-the-rayCloud
Best,
Teodora
Não esta sendo processado o orthomosaico no pix4Dcloud
Alguem pode me ajudar ?
Hola Joice, por favor describe el problema con más detallas en nuestro Foro.
Is it possible to export a single 5 band tiff as a reflectance map from Pix4D Mapper? I am struggling to find this in the documentation and export files.
Crockett, Unfortunately, that is not possible. You will need to use the single band reflectance maps and then make a 5 band composite in QGIS or ArcGIS.
Hello, I am having difficulty uploading a orthomosaic into a cloud project. The DSM is uploading and showing in the right spot but the Orthomosaic is not showing up at all. I have processed locally and I'm pretty sure I've used the correct coordinate system.
This error is expected for outputs having a significant size and/or a complex geometry. In this case, the tiling process failed, meaning that the generated 2D output could not be split into smaller web maps (tiles) for several zoom levels and, for this reason, the output cannot be displayed. You can reduce the resolution in QGIS or Pix4D and upload again.
I was wondering is the orthomosaic included in the free trial version?
I've downloaded Pix4Ddiscovery and I can only merge rasters to pointclouds but I need to merge them to a new raster
If this is not possible with the version I got and the trial, is there a possibility that I could use this on free base?
Greetings, Niek
The trial version has all the features. Pix4D discovery is our free version and some features are disabled. If you do not have a trial and want one, I would recommend reaching out to the sales team.
I left my computer on to process step 3 overnight. When I woke up the computer had restarted. After logging into Pix4D I see that Step 3 is now green in the processing workflow but I don't see my orthomosiac in the folder. Does this mean that Step 3 didn't really finish?
Can you check the processing options to see if geotiff was enabled?
If not, the orthomosaic will not be generated. In that case, you have to enable the outputs you need, and process step 3 again.