Reduce group size to 40 tiles in width.

Author: ericboucher

import_module/create_groups.py

@@ -232,7 +232,7 @@ def get_vertical_slice(slice_infos, zoom):
     # the final group polygon is calculated from TileX_min, TileX_max, TileY_min, TileY_max
 
     # the width threshold defines how "long" the groups are
-    width_threshold = 70
+    width_threshold = 40
     # create an empty dict for the group ids and TileY_min, TileY_may, TileX_min, TileX_max
     raw_groups = {}
     group_id = 100

import_module/readme.md

@@ -50,7 +50,7 @@ The grouping algorithm creates a `.json` file that can be uploaded into firebase
 * slice input polygon horizontally (`get_horizontal_slice(extent, geomcol, config['zoom'])`)
     * All created slices will have a height of three tiles
 * slice horizontal slices again, but now vertically (`get_vertical_slice(horizontal_slice, config['zoom'])`)
-    * The `width_threshold` parameter specified in the script defines how *long* the groups will be. Currently we use a width of 70 tiles.
+    * The `width_threshold` parameter specified in the script defines how *long* the groups will be. Currently we use a width of 40 tiles.
 * create tasks for each group polygon and add to the group dictionary (`create_tasks(xmin, xmax, ymin, ymax, config)`)
 
 <img src="../img/project.png" width="250px"> <img src="../img/horizontally_sliced_groups.png" width="250px"> <img src="../img/vertically_sliced_groups.png" width="250px">

mapswipe_data_model.md

@@ -31,7 +31,7 @@ To create a new mapping task, the overall project extent is split up into many s
 | **Tile URL** | The tile URL points to the specific tile image described by the x, y, and z coordinates. Usually, the image has a resolution of 256 x 256 pixels. However, some providers also generate image tiles with higher resolution (e.g. 512 x 512 pixels). |
 
 ## Groups
-Single MapSwipe projects can contain up to several hundred thousand tasks. This can pose a challenge to fast and performant communication between clients and server if many volunteers contribute data at the same time. Therefore, groups have been introduced to reduce the amount of client requests on the backend server. Groups consists of several tasks, that will be shown to the user in one mapping session. The grouping algorithm uses the extent of a project as an input and generates chunks of tasks lying next to each other. Each group has a height of three tasks and a width of approximately 70 tasks.
+Single MapSwipe projects can contain up to several hundred thousand tasks. This can pose a challenge to fast and performant communication between clients and server if many volunteers contribute data at the same time. Therefore, groups have been introduced to reduce the amount of client requests on the backend server. Groups consists of several tasks, that will be shown to the user in one mapping session. The grouping algorithm uses the extent of a project as an input and generates chunks of tasks lying next to each other. Each group has a height of three tasks and a width of approximately 40 tasks.
 
 | Parameter | Description |
 | --- | --- |