lazread

out = lazread(FileName::AbstractString; out::String="xyz", do_grid=false, do_image=false,
              type::DataType=Float64, class=0, startstop="1:end")

Read data from a LIDAR laz (laszip compressed) or las format file.

Args

• FileName: Name of the input LIDAR file.

Kwargs

• out: Select what data to output. The default is "xyz" meaning that only these three are sent out. Examples include: "xyz", "xy", "yx", "z", "xyzi", "xyzt", "xyzit", "xyzti", "xyzic" "xyzc", "RGB", "RGBI", "xyRGB", "xyRGBI". where 'i' stands for intensity (UInt16), 'c' for classification (Int8) and 't' for GPS time (Float64)

• do_grid: If true, the output is a GMTgrid. This implicitly sets out="xyz" and type=Float32. The grid is built using the nearneighbor algorithm. It is recommended to use the -R and -I options, but if not provided, the grid is built using the extent of the data and a crude estimate of the increment.

• do_image: If true, the output is a GMTimage. This implicitly sets out="xyRGB" and of course it will error if the laz file does not contain RGB data. If another color combination is desired, specify it explicitly, e.g., out="xyIRG". Like the do_grid option, it is recommended to use the -R and -I options, to control the image extent and resolution.

• type: The float components (xyz) may be required in Float32. The default is Float64.

• startstop="start:stop": A string that restricts the output to the points from start to stop.

• class: Restrict the output to the points belonging to the classification 'class' (an Integer). This option implies two passes, with the first for counting the number of points in class.

Returns

out is Type with the folowing fields: stored, grd, img, ds, dsv, where stored is a string indicating what data is stored in output. grd is a GMTgrid if grid is true or we read a grided laz file. img is a GMTimage if image was set to true and the laz file contains RGB data. ds is a GMTdataset with the xyz data, and dsvis a vector of GMTdataset if input opion out was set to something else than "xyz" or "xy". The reason for assembling the output in a Type is make the output of lazread be type stable. Use getproperty(out, Symbol(out.stored)) toget the normal GMT types directly, or, do the reading via gmtread that will do this for you.

Example

To write the x,y,z data to file "lixo.laz" do:

D = gmtread(TESTSDIR * "/assets/test.laz")

See Also

lazwrite, gmtread