Texas Basemap - Transportation Map Data

This resource contains statewide networks of roadways, railroads, bridges, and low-water crossings, for Texas only.

Roadways detail: The Transportation Planning and Programming (TPP) Division of the Texas Department of Transportation (TxDOT) maintains a spatial dataset of roadway polylines for planning and asset inventory purposes, as well as for visualization and general mapping. M values are stored in the lines as DFOs (Distance From Origin), and provide the framework for managing roadway assets using linear referencing. This dataset covers the state of Texas and includes on-systems routes (those that TxDOT maintains), such as interstate highways, U.S. highways, state highways, and farm and ranch roads, as well as off-system routes, such as county roads and local streets. Date valid as of: 12/31/2014. Publish Date: 05/01/2015. Update Frequency: Quarterly.

Bridges detail: As with the roadways, both on-system and off-system bridges are maintained in separate datasets (54,844 total bridges, 36,007 on-system and 18,837 off-system). Bridges have numerous useful attributes, see coding guide [1] for documentation. One such attribute identifies structures that cross water: the second digit of Item 42 “Type of Service”. If the second digit is between 5 and 9 (inclusive) then the structure is over water. The bridges datasets are valid as of December 2016.

The roadways and bridges datasets contained here were obtained directly from TxDOT through personal correspondence. An additional transportation data resource is the Texas Natural Resources Information System (TNRIS) [3]. The railroads and low-water crossings were obtained through TNRIS.

November 2023 updates: in the years since this data archive was first published, TxDOT has developed an open data portal for downloading their roadway inventory and other datasets. Also, in 2023 TNRIS was renamed as the Texas Geographic Information Office (TxGIO). Their datahub [3] is continually evolving, but still has the tnris.org domain for now. We are not updating any of the basemap data in the contents list below, which was current at the time of Hurricane Harvey.

References
[1] TxDOT Bridges Coding Guide (download below)
[2] TxDOT Open Data Portal [https://gis-txdot.opendata.arcgis.com/]
[3] TNRIS/TxGIO data downloads [https://data.tnris.org/]

本资源仅针对得克萨斯州（Texas），包含全州范围内的道路、铁路、桥梁及浅滩渡口空间网络。

道路详情：得克萨斯州交通运输部（Texas Department of Transportation, TxDOT）交通规划与项目（Transportation Planning and Programming, TPP）部门维护一套道路折线空间数据集，用于规划、资产盘点、可视化及通用制图。该数据集中的折线存储了起点距离（Distance From Origin, DFO）值的M属性，为基于线性参考的道路资产管理提供了框架。本数据集覆盖得克萨斯州全域，包含TxDOT维护的系统内路线（如州际公路、美国国道、州道及农牧场道路），以及系统外路线（如县道及地方街道）。数据生效日期：2014年12月31日；发布日期：2015年5月1日；更新频率：季度更新。

桥梁详情：与道路数据集类似，系统内及系统外桥梁分别存储于独立数据集（总计54844座桥梁，其中系统内36007座，系统外18837座）。桥梁包含多项实用属性，详见编码指南[1]。其中一项属性用于标识跨水结构：即第42项“服务类型”的第二位数字。若该数字介于5至9（含边界）之间，则该结构为跨水建筑。本桥梁数据集生效日期为2016年12月。

本次提供的道路与桥梁数据集直接通过私人通信渠道从TxDOT获取。另有一项交通数据资源为得克萨斯州自然资源信息系统（Texas Natural Resources Information System, TNRIS）[3]，本资源中的铁路及浅滩渡口数据即通过该系统获取。

2023年11月更新说明：自本数据档案首次发布以来，TxDOT已开发开放数据门户，用于下载其道路盘点及其他数据集。此外，TNRIS于2023年更名为得克萨斯地理信息办公室（Texas Geographic Information Office, TxGIO）。其数据枢纽[3]仍在持续迭代，目前仍使用tnris.org域名。本资源未对下述内容列表中的底图数据进行更新，该批数据在哈维飓风发生时仍为最新版本。

参考文献
[1] TxDOT桥梁编码指南（下载见下方）
[2] TxDOT开放数据门户 [https://gis-txdot.opendata.arcgis.com/]
[3] TNRIS/TxGIO数据下载 [https://data.tnris.org/]