diff --git a/driptorch/firing/strip_contour.py b/driptorch/firing/strip_contour.py
index 1944e7a..a6ea15e 100644
--- a/driptorch/firing/strip_contour.py
+++ b/driptorch/firing/strip_contour.py
@@ -112,7 +112,7 @@ def _init_paths(self, paths: dict, **kwargs) -> dict:
                             source_line, neighborhood_size=1, z_multiplier=elevation_influence)
 
         # Determine level set values for ignition path slicing
-        if heat_depth == depth:
+        if not heat_depth or heat_depth == depth:
             levels = range(depth, int(np.max(cost_distance.data)), depth)
         else:
             levels = [depth]
diff --git a/driptorch/io.py b/driptorch/io.py
index 6eb1fe3..6011534 100644
--- a/driptorch/io.py
+++ b/driptorch/io.py
@@ -15,6 +15,7 @@
 from shapely.geometry.base import BaseGeometry
 from shapely.ops import transform
 from typing import Union
+import copy
 
 
 class Projector:
@@ -183,7 +184,7 @@ def read_geojson_polygon(geojson: dict) -> Polygon:
 
 
 def write_geojson(geometries: list[BaseGeometry], src_epsg: int, dst_epsg: int = 4326, properties={},
-                  style={}, elapsed_time=None) -> dict:
+                  style={}, elapsed_time=None, max_line_segment_time=None, path_properties: list[dict]=None) -> dict:
     """Write a list of shapely geometries to GeoJSON
 
     Parameters
@@ -200,7 +201,10 @@ def write_geojson(geometries: list[BaseGeometry], src_epsg: int, dst_epsg: int =
         Rendering style applied to all features. Defaults to {}.
     elapsed_time : float, optional
         Time elapsed during the firing operation. Defaults to None.
-
+    max_line_segment_time : int, optional
+        Maximum time (in milliseconds) for a line segment.
+    path_properties : list[dict], optional
+        Properties for each segment of the path.
     Returns
     -------
     dict
@@ -218,17 +222,95 @@ def write_geojson(geometries: list[BaseGeometry], src_epsg: int, dst_epsg: int =
     for i, geometry in enumerate(geometries):
 
         props = {}
+        # add properties
         for name in property_names:
             props[name] = properties[name][i]
 
+        # add style
+        props.update(style)
+
+        # add any path_properties for this segment of the path
+        if path_properties is not None:
+            props.update(path_properties[i])     
+
         features.append(
             {
                 'type': 'Feature',
-                'properties': props | style,
+                'properties': props,
                 'geometry': mapping(projector.forward(geometry))
             }
         )
 
+    if max_line_segment_time is not None and 'times' in features[0]['properties']:
+       
+        new_features = []
+
+        for feature in features:
+
+            # only split lines
+            if feature['geometry']['type'] != 'LineString':
+                new_features.append(copy.deepcopy(feature))
+                continue
+
+            times = feature['properties']['times']
+            coords = feature['geometry']['coordinates']
+            prev_idx = 0
+            cur_idx = 0
+
+            while cur_idx < len(times):
+
+                while times[cur_idx] - times[prev_idx] > max_line_segment_time:
+
+                    # create a new feature ending at previous time + max time
+                    end_time = times[prev_idx] + max_line_segment_time
+                    new_times = times[prev_idx:cur_idx] + [end_time]
+
+                    fraction = max_line_segment_time / (times[cur_idx] - times[prev_idx])
+
+                    # calculate distance for accumulated line
+                    distance = LineString(coords[prev_idx:cur_idx+1]).length
+
+                    max_distance = distance * fraction
+
+                    # find the segment where the distance along accumulated line
+                    # is past the max distance
+                    accum_idx = prev_idx
+                    accum_distance = 0
+                    while accum_distance < max_distance:
+                        next_distance = Point(coords[accum_idx]).distance(Point(coords[accum_idx+1]))
+                        accum_distance += next_distance
+                        accum_idx += 1
+
+                    subfraction = (max_distance - (accum_distance - next_distance)) / next_distance
+
+                    new_x = coords[accum_idx-1][0] + (coords[accum_idx][0] - coords[accum_idx-1][0]) * subfraction
+                    new_y = coords[accum_idx-1][1] + (coords[accum_idx][1] - coords[accum_idx-1][1]) * subfraction
+                    end_coords = (new_x, new_y)
+                    new_coords = coords[prev_idx:accum_idx] + (end_coords,)
+
+                    new_feature = copy.deepcopy(feature)
+                    new_feature['properties']['times'] = new_times
+                    new_feature['geometry']['coordinates'] = new_coords
+                    new_features.append(new_feature)
+
+                    # modify current feature to start at previous time + max_line_segment_time
+                    feature['properties']['times'] = [end_time] + times[accum_idx:]
+                    feature['geometry']['coordinates'] = (end_coords,) + coords[accum_idx:]
+                    times = feature['properties']['times']
+                    coords = feature['geometry']['coordinates']
+
+                    prev_idx = 0
+                    cur_idx = 0
+            
+                cur_idx += 1
+            
+        
+            if len(times) > 0:
+                new_features.append(copy.deepcopy(feature))
+
+
+        features = new_features
+
     # Compile the features in a feature collection
     geojson = {
         'type': 'FeatureCollection',
diff --git a/driptorch/pattern.py b/driptorch/pattern.py
index 7c4bb66..891f885 100644
--- a/driptorch/pattern.py
+++ b/driptorch/pattern.py
@@ -4,7 +4,6 @@
 
 # Core imports
 from __future__ import annotations
-import pdb
 import copy
 from time import time as unix_time
 import warnings
@@ -56,10 +55,12 @@ class Pattern:
         Path geometry
     epsg : int
         EPSG code for path geometry
+    properties: list[dict], optional
+        Set of properties of the path
     """
 
     def __init__(self, heat: list[int], igniter: list[int], leg: list[int], times: list[list[float]],
-                 geometry: list[LineString], epsg: int,
+                 geometry: list[LineString], epsg: int, properties: list[dict] = None
                  ):
 
         self.heat = heat
@@ -69,6 +70,10 @@ def __init__(self, heat: list[int], igniter: list[int], leg: list[int], times: l
         self.geometry = geometry
         self.epsg = epsg
 
+        self.properties = properties
+        if self.properties is None:
+            self.properties = [{} for _ in range(len(heat))]
+
         # Compute the total elapsed time for the ignition crew
         times_ak = ak.Array(self.times)
         min_time = ak.min(times_ak)
@@ -76,7 +81,7 @@ def __init__(self, heat: list[int], igniter: list[int], leg: list[int], times: l
         self.elapsed_time = max_time - min_time
 
     @classmethod
-    def from_dict(cls, paths_dict: dict, epsg: int) -> Pattern:
+    def from_dict(cls, paths_dict: dict, epsg: int = None) -> Pattern:
         """Alternative constructor for initializing a Pattern object with a dictionary
         of path parameters
 
@@ -85,7 +90,7 @@ def from_dict(cls, paths_dict: dict, epsg: int) -> Pattern:
         paths_dict : dict
             Dictionary of path parameters
         epsg : Int
-            EPSG code of path geometries
+            EPSG code of path geometries. If not specified, epsg must by in paths_dict
 
         Returns
         -------
@@ -93,7 +98,18 @@ def from_dict(cls, paths_dict: dict, epsg: int) -> Pattern:
             A new instance of Pattern
         """
 
+        if epsg is None:
+            if 'epsg' not in paths_dict:
+                raise ValueError('epsg not specified and not in paths_dict')
+            epsg = paths_dict['epsg']
+            
         paths_dict["geometry"] = [shape(x) for x in paths_dict["geometry"]]
+
+        if 'properties' in paths_dict:
+            properties = paths_dict["properties"]
+        else:
+            properties = [{} for _ in range(len(paths_dict["heat"]))]
+
         return cls(
             paths_dict["heat"],
             paths_dict["igniter"],
@@ -101,6 +117,7 @@ def from_dict(cls, paths_dict: dict, epsg: int) -> Pattern:
             paths_dict["times"],
             paths_dict["geometry"],
             epsg,
+            properties,
         )
 
     def to_dict(self) -> dict:
@@ -117,6 +134,8 @@ def to_dict(self) -> dict:
             "igniter": self.igniter,
             "leg": self.leg,
             "times": self.times,
+            "epsg": self.epsg,
+            "properties": self.properties,
             # convert to geoJSON for storage
             "geometry": [x.__geo_interface__ for x in self.geometry],
         }
@@ -133,9 +152,14 @@ def empty_path_dict() -> dict:
 
         return {"heat": [], "igniter": [], "leg": [], "geometry": []}
 
-    def to_json(self) -> dict:
+    def to_json(self, max_line_segment_time=None) -> dict:
         """Write the Pattern to a GeoJSON dictionary
 
+        Parameters
+        ----------
+        max_line_segment_time : int, optional
+            Maximum time (in milliseconds) for a line segment.
+
         Returns
         -------
         dict
@@ -176,6 +200,8 @@ def to_json(self) -> dict:
             properties=props,
             style=style,
             elapsed_time=self.elapsed_time,
+            max_line_segment_time=max_line_segment_time,
+            path_properties=self.properties
         )
 
     def translate(self, x_off: float, y_off: float) -> Pattern:
@@ -275,15 +301,19 @@ def to_quicfire(self, burn_unit: BurnUnit, filename: str = None, time_offset=0,
                 geometry, times, self.elapsed_time, resolution=resolution
             )
 
-    def merge(self, pattern: Pattern, time_offset: float = 0, inplace: bool = False) -> Pattern:
+    def merge(self, pattern: Pattern, time_offset: float = 0, time_offset_end: bool = True, inplace: bool = False) -> Pattern:
         """Merge an input pattern with self
 
         Parameters
         ----------
         pattern : Pattern
             Input pattern to be merged into self
-        time_offset : float
-            Time offset between patterns (seconds)
+        time_offset : float, optional
+            Time offset for other pattern. See time_offset_end for when other pattern executes in parallel or
+            sequentially this self pattern. (seconds)
+        time_offset_end : bool, optional
+            If true, patterns are executed sequentially and time_offset is the time between patterns.
+            Otherwise, patterns are executed in parallel and time_offset is the delayed start time for the other pattern.
         inplace : bool, optional
             Overwrites Pattern object if true, otherwise return new Pattern object. Defaults to True.
 
@@ -304,10 +334,16 @@ def merge(self, pattern: Pattern, time_offset: float = 0, inplace: bool = False)
         # Get an empty path dictionary
         merged_dict = self.empty_path_dict()
 
-        # Delay times in the second pattern by the elapsed time of the first pattern and offset
-        delayed_times = (
-            ak.max(self.times) + time_offset + ak.Array(pattern.times)
-        ).to_list()
+        if time_offset_end:
+            # Delay times in the second pattern by the elapsed time of the first pattern and offset
+            delayed_times = (
+                ak.max(self.times) + time_offset + ak.Array(pattern.times)
+            ).to_list()
+        else:
+            # Delay times in the second pattern by the offset
+            delayed_times = (
+                time_offset + ak.Array(pattern.times)
+            ).to_list()
 
         # Build merged pattern attributes
         merged_dict["heat"] = self.heat + pattern.heat
@@ -315,14 +351,20 @@ def merge(self, pattern: Pattern, time_offset: float = 0, inplace: bool = False)
         merged_dict["leg"] = self.leg + pattern.leg
         merged_dict["times"] = self.times + delayed_times
         merged_dict["geometry"] = self.geometry + pattern.geometry
+        merged_dict["properties"] = self.properties + pattern.properties
 
         # Instantiate a new Pattern object
         merged_pattern = self.from_dict(merged_dict, self.epsg)
 
         # Compute summed elapse time
-        merged_pattern.elapsed_time = (
-            self.elapsed_time + time_offset + pattern.elapsed_time
-        )
+        if time_offset_end:
+            merged_pattern.elapsed_time = (
+                self.elapsed_time + time_offset + pattern.elapsed_time
+            )
+        else:
+            merged_pattern.elapsed_time = (
+                max(self.elapsed_time, time_offset + pattern.elapsed_time)
+            )
 
         # If inplace then overwrite self with the merged pattern
         if inplace:
diff --git a/driptorch/unit.py b/driptorch/unit.py
index 425dc32..20d765c 100644
--- a/driptorch/unit.py
+++ b/driptorch/unit.py
@@ -15,7 +15,7 @@
 
 # External imports
 import numpy as np
-from shapely.geometry import Polygon, LineString, Point
+from shapely.geometry import Polygon, LineString, Point, MultiPolygon
 from shapely import affinity
 
 
@@ -183,6 +183,17 @@ def buffer_downwind(self, width: float) -> BurnUnit:
         # buffer to cut out the downfiring blackline area
         buffered_polygon = self.polygon.difference(fore_line_buffer)
 
+        if isinstance(buffered_polygon, MultiPolygon):
+            print('WARNING: downwind buffered geometry is multipolygon; using only largest polygon.')
+            multi = list(buffered_polygon)
+            max_area = -999999
+            for poly in multi:
+                if poly.area > max_area:
+                    max_area = poly.area
+                    max_poly = poly
+
+            buffered_polygon = max_poly
+
         return BurnUnit(buffered_polygon, self.firing_direction, utm_epsg=self.utm_epsg)
 
     def difference(self, burn_unit: BurnUnit) -> BurnUnit:
diff --git a/setup.py b/setup.py
index 53e054a..b8b14ca 100644
--- a/setup.py
+++ b/setup.py
@@ -35,7 +35,7 @@
         'pandas==1.4.2',
         'pyproj==3.3.1',
         'folium==0.12.1.post1',
-        'gcsfs==2022.1.0',
+        'gcsfs==2024.2.0',
         'zarr==2.13.3',
         'scipy==1.9.3',
         'scikit-image==0.19.3'