Add method to multiple extra dimensions at once

Its more efficient to add many extra dimensions at once.

Also change the the second style name used for float and double from 'float' to 'float32' and 'double' to 'float64' to match numpy:

  str(np.dtype('double')) = 'float64'
  str(np.dtype('float64')) = 'float64'
  str(np.dtype('f8')) = 'float64'

docs/basic.rst

@@ -33,7 +33,7 @@ if you need metada informations that are contained in the header.
 
 Sometimes files are big, too big to be read entirely and fit into your RAM.
 The object returned by the :func:`pylas.open` function, :class:`pylas.lasreader.LasReader`
-can also be used to read points chunk by chunk, which will allow you to do some
+can also be used to read points chunk by chunk by using :meth:`pylas.lasreader.LasReader.chunk_iterator`, which will allow you to do some
 processing on large files (splitting, filtering, etc)
 
 .. code:: python

docs/lessbasic.rst

@@ -33,9 +33,9 @@ The Allowed base types for an extra dimensions are:
 +-------------------------+-------------+-------------+
 |     i8 or int64         |     64      |    signed   |
 +-------------------------+-------------+-------------+
-|     f4 or float         |     32      |   floating  |
+|     f4 or float32       |     32      |   floating  |
 +-------------------------+-------------+-------------+
-|     f8 or double        |     64      |   floating  |
+|     f8 or float32       |     64      |   floating  |
 +-------------------------+-------------+-------------+
 
 You can prepend the number '2' or '3' to one of the above base type to define an extra dimension
@@ -63,6 +63,13 @@ and an array field of 3 doubles for each points.
     Although the specification of the ExtraBytesVlr appeared in the 1.4 LAS Spec, pylas allows to
     add new dimensions to file with version < 1.4
 
+.. note::
+
+   If you are adding multiple extra dimensions use :meth:`pylas.LasBase.add_extra_dims`
+   as it is more efficient (it allows to allocate all the dimensions at once instead
+   of re-allocating each time a new dimension is added.
+
+
 Custom VLRs
 ===========
 

pylas/extradims.py

@@ -24,8 +24,8 @@
     "int32",
     "uint64",
     "int64",
-    "float",
-    "double",
+    "float32",
+    "float64",
 )
 
 _extra_dims_style_1_array_2 = tuple(

pylas/lasdatas/base.py

@@ -1,6 +1,6 @@
 import logging
 import pathlib
-from typing import Union, Optional
+from typing import Union, Optional, Tuple, List
 
 import numpy as np
 
@@ -157,6 +157,12 @@ def __setitem__(self, key, value):
     def add_extra_dim(self, name: str, type: str, description: str = ""):
         """Adds a new extra dimension to the point record
 
+        .. note::
+
+            If you plan on adding multiple extra dimensions,
+            prefer :meth:`pylas.LasBase.add_extra_dims` as it will
+            save re-allocations and data copy
+
         Parameters
         ----------
         name: str
@@ -166,22 +172,43 @@ def add_extra_dim(self, name: str, type: str, description: str = ""):
         description: str, optional
             a small description of the dimension
         """
-        name = name.replace(" ", "_")
-        type_id = extradims.get_id_for_extra_dim_type(type)
-        # convert to u1, i2, style
-        type = extradims.get_type_for_extra_dim(type_id)
-        extra_byte = ExtraBytesStruct(
-            data_type=type_id, name=name.encode(), description=description.encode()
-        )
+        self.add_extra_dims([(name, type, description)])
+
+    def add_extra_dims(self, type_tuples: List[Tuple[str,...]]):
+        """ Add multiple extra dimensions at once
+
+        Parameters
+        ----------
+
+        type_tuples:
+               a list of tuple describing the dimensions to add
+               [(name, type, description), (name2, other_type)]
+               The description is optional
+        """
+        extra_bytes_structs = []
+        tuples = []
+        for name, type, *rest in type_tuples:
+            name = name.replace(" ", "_")
+            if rest:
+                description = rest[0]
+            else:
+                description = ""
+            type_id = extradims.get_id_for_extra_dim_type(type)
+            tuples.append((name, extradims.get_type_for_extra_dim(type_id)))
+            extra_bytes_structs.append(ExtraBytesStruct(
+                data_type=type_id, name=name.encode(), description=description.encode()
+            ))
 
         try:
             extra_bytes_vlr = self.vlrs.get("ExtraBytesVlr")[0]
         except IndexError:
             extra_bytes_vlr = ExtraBytesVlr()
             self.vlrs.append(extra_bytes_vlr)
         finally:
-            extra_bytes_vlr.extra_bytes_structs.append(extra_byte)
-            self.points.add_extra_dim(name, type)
+            extra_bytes_vlr.extra_bytes_structs.extend(extra_bytes_structs)
+            self.points.add_extra_dims(tuples)
+
+
 
     def update_header(self):
         """Update the information stored in the header

pylas/point/dims.py

@@ -324,7 +324,7 @@ def from_type_str(
         first_digits = "".join(itertools.takewhile(lambda l: l.isdigit(), type_str))
         if first_digits:
             num_elements = int(first_digits)
-            type_str = type_str[len(first_digits) :]
+            type_str = type_str[len(first_digits):]
         else:
             num_elements = 1
 

pylas/point/record.py

@@ -5,7 +5,7 @@
 """
 import logging
 from abc import ABC, abstractmethod
-from typing import NoReturn, Any
+from typing import NoReturn, Any, List, Tuple
 
 import numpy as np
 
@@ -151,12 +151,16 @@ def copy_fields_from(self, other_record):
             except ValueError:
                 pass
 
-    def add_extra_dim(self, name, type_tuple):
-        self.point_format.add_extra_dimension(name, type_tuple)
+    def add_extra_dims(self, dim_tuples: List[Tuple[str, str]]):
+        for name, type_str in dim_tuples:
+            self.point_format.add_extra_dimension(name, type_str)
         old_array = self.array
         self._array = np.zeros_like(old_array, dtype=self.point_format.dtype())
         self.copy_fields_from(old_array)
 
+    def add_extra_dim(self, name, type_str):
+        self.add_extra_dims([(name, type_str)])
+
     def memoryview(self):
         return memoryview(self.array)