Fix 3 data path imports in gis models (projectmesa#176)

Fix the data path import errors in the geo_schelling, geo_schelling_points and geo_sir models.

gis/geo_schelling/model.py

@@ -1,8 +1,11 @@
+import os
 import random
 
 import mesa
 import mesa_geo as mg
 
+script_directory = os.path.dirname(os.path.abspath(__file__))
+
 
 class SchellingAgent(mg.GeoAgent):
     """Schelling segregation agent."""
@@ -67,7 +70,10 @@ def __init__(self, density=0.6, minority_pc=0.2, export_data=False):
 
         # Set up the grid with patches for every NUTS region
         ac = mg.AgentCreator(SchellingAgent, model=self)
-        agents = ac.from_file("data/nuts_rg_60M_2013_lvl_2.geojson")
+        data_path = os.path.join(
+            script_directory, "data/nuts_rg_60M_2013_lvl_2.geojson"
+        )
+        agents = ac.from_file(filename=data_path)
         self.space.add_agents(agents)
 
         # Set up agents

gis/geo_schelling_points/geo_schelling_points/model.py

@@ -1,3 +1,4 @@
+import os
 import random
 import uuid
 
@@ -7,6 +8,8 @@
 from .agents import PersonAgent, RegionAgent
 from .space import Nuts2Eu
 
+script_directory = os.path.dirname(os.path.abspath(__file__))
+
 
 class GeoSchellingPoints(mesa.Model):
     def __init__(self, red_percentage=0.5, similarity_threshold=0.5):
@@ -24,9 +27,10 @@ def __init__(self, red_percentage=0.5, similarity_threshold=0.5):
 
         # Set up the grid with patches for every NUTS region
         ac = mg.AgentCreator(RegionAgent, model=self)
-        regions = ac.from_file(
-            "data/nuts_rg_60M_2013_lvl_2.geojson", unique_id="NUTS_ID"
+        data_path = os.path.join(
+            script_directory, "../data/nuts_rg_60M_2013_lvl_2.geojson"
         )
+        regions = ac.from_file(data_path, unique_id="NUTS_ID")
         self.space.add_regions(regions)
 
         for region in regions:

gis/geo_sir/model.py

@@ -1,15 +1,21 @@
+import os
+
 import mesa
 import mesa_geo as mg
 from shapely.geometry import Point
 
 from .agents import NeighbourhoodAgent, PersonAgent
 
+script_directory = os.path.dirname(os.path.abspath(__file__))
+
 
 class GeoSir(mesa.Model):
     """Model class for a simplistic infection model."""
 
     # Geographical parameters for desired map
-    geojson_regions = "data/TorontoNeighbourhoods.geojson"
+    geojson_regions = os.path.join(
+        script_directory, "data/TorontoNeighbourhoods.geojson"
+    )
     unique_id = "HOODNUM"
 
     def __init__(