Spatial Morphology Lab 01. International laboratory for comparative research in urban form. Street networks, Sweden - Motorised network of Västra Götaland

GIS-datasets for the Street networks of Stockholm, Gothenburg and Eskilstuna produced as part of the Spatial Morphology Lab (SMoL).

The goal of the SMoL project is to develop a strong theory and methodology for urban planning & design research with an analytical approach. Three frequently recurring variables of spatial urban form are studied that together quite well capture and describe the central characteristics and qualities of the built environment: density, diversity and proximity.

The first measure describes how intensive a place can be used depending on how much built up area is found there. The second measure captures how differentiated the use of a place can be depending on the division in smaller units such as plots. The third measure describes how accessible a place is depending on how it relates with other places. Empirical studies have shown strong links between these metrics and people's use of cities such as pedestrian movement patterns.

To support this goal, a central objective of the project is the establishment of an international platform of GIS data models for comparative studies in spatial urban form comprising three European capitals: London in the UK, Amsterdam in the Netherlands and Stockholm in Sweden, as well as two additional Swedish cities of smaller size than Stockholm: Gothenburg and Eskilstuna.

The result of the project is a GIS database for the five cities covering the three basic layers of urban form: street network (motorised and non-motorised), buildings and plots systems.

The data is shared via SND to create a research infrastructure that is open to new study initiatives. The datasets for Amsterdam will also be uploaded to SND. The datasets of London cannot be uploaded because of licensing restrictions.

The street network GIS-maps include motorised and non-motorised networks. The motorised networks exclude all streets that are pedestrian-only and were cars are excluded. The network layers are based on the Swedish national road database, NVDB (Nationell Vägdatabas), downloaded from Trafikverket (https://lastkajen.trafikverket.se, date of download 15-5-2016, last update 8-11-2015). The original road-centre-line maps of all cities were edited based on the same basic representational principles and were converted into line-segment maps, using the following software: FME, Mapinfo professional and PST (Place Syntax Tool). The coordinate system is SWEREF99TM. The map covers all Västra Götaland region (Västra Götalands län).

In the final line-segment maps (GIS-layers) all roads are represented with one line irrespectively of the number of lanes, except from Motorways and Highways which are represented with two lines, one for each direction, again irrespectively of the number of lanes. We followed the same editing and generalizing procedure for all maps aiming to remove errors and to increase comparability between networks. This process included removing duplicate and isolated lines, snapping and generalizing. The snapping threshold used was 2m (end points closer than 2m were snapped together). The generalizing threshold used was 1m (successive line segments with angular deviation less than 1m were merged into one). In the final editing step, all road polylines were segmented to their constituting line-segments. The aim was to create appropriate line-segment maps to be analysed using Angular Segment Analysis, a network centrality analysis method introduced in Space Syntax.

All network layers are complemented with an “Unlink points” layer; a GIS point layer with the locations of all non-level intersections, such as overpasses and underpasses, bridges, tunnels, flyovers and the like. The Unlink point layer is necessary to conduct network analysis that takes into account the non-planarity of the street network, using such software as PST (Place Syntax Tool).

本数据集为空间形态实验室（Spatial Morphology Lab，缩写SMoL）项目产出的斯德哥尔摩、哥德堡与埃斯基尔斯蒂纳的街道网络地理信息系统（Geographic Information System，简称GIS）数据集。

SMoL项目的核心目标是依托分析性方法，构建用于城市规划与设计研究的成熟理论与方法论体系。研究聚焦于空间城市形态中三大高频变量，这三大变量可较为全面地捕捉并描述建成环境的核心特征与品质：密度、多样性与可达性。

第一项指标衡量某一区域的开发强度，取决于该区域的建成用地占比；第二项指标反映某一区域的用地分化程度，取决于地块等细分单元的划分情况；第三项指标描述某一区域的可达性，取决于其与其他区域的空间关联关系。实证研究表明，这些指标与城市人群活动（如步行流动模式）存在显著关联。

为支撑该目标，本项目的核心任务是搭建一个用于空间城市形态比较研究的GIS数据模型国际平台，涵盖五座欧洲城市：英国伦敦、荷兰阿姆斯特丹、瑞典斯德哥尔摩，以及两座规模小于斯德哥尔摩的瑞典城市——哥德堡与埃斯基尔斯蒂纳。

本项目最终产出了覆盖上述五座城市的GIS数据库，涵盖城市形态的三大基础图层：街道网络（机动车与非机动车）、建筑与地块系统。

该数据集通过瑞典国家数据服务平台（SND）共享，旨在打造开放的研究基础设施，接纳新的研究项目。阿姆斯特丹的数据集也将上传至SND，而伦敦的数据集因授权限制无法公开上传。

本次产出的街道网络GIS地图包含机动车与非机动车网络两类图层。其中机动车网络排除所有仅允许行人通行、禁止机动车驶入的道路。网络图层基于瑞典国家道路数据库（Nationell Vägdatabas，简称NVDB）构建，该数据由瑞典交通管理局（Trafikverket）于2016年5月15日下载（最后更新日期为2015年11月8日，下载地址：https://lastkajen.trafikverket.se）。所有城市的原始道路中心线地图均遵循统一的基础表征原则进行编辑，并通过FME、MapInfo Professional与Place Syntax Tool（简称PST）三款软件转换为线段地图。坐标系采用SWEREF99TM。地图覆盖西约塔兰省（Västra Götalands län）全域。

在最终的线段地图（GIS图层）中，除高速公路与快速路外，所有道路均以单条线段表示，不考虑车道数量；高速公路与快速路则以双线段分别表示双向车流，同样不考虑车道数量。我们对所有地图采用统一的编辑与概化流程，以消除错误并提升不同网络间的可比性。该流程包括删除重复与孤立线段、节点匹配与线条概化。本次使用的节点匹配阈值为2米（间距小于2米的端点将被合并），线条概化阈值为1米（连续线段间的角偏差小于1米时，将其合并为单一线段）。在最终编辑步骤中，所有道路多段线均被拆分为其组成的单一线段，旨在生成适用于角段分析法（Angular Segment Analysis）的线段地图——该方法是空间句法（Space Syntax）提出的网络中心性分析手段。

所有网络图层均配套有“非平面交点”图层：这是一类GIS点图层，标注所有非平面交叉口的位置，包括立交桥、地下通道、桥梁、隧道、高架道路等。借助PST等软件开展考虑街道网络非平面性的网络分析时，该非平面交点图层为必备图层。