OpenStreetMap Toolbox For MATLAB V.0.1 User Manual V0.2
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User Manual OpenStreetMap Functions for MATLAB v.0.2 Ioannis F. Filippidis Control Systems Lab Department of Mechanical Engineering National Technical University of Athens Athens, Greece jfilippidis@gmail.com Date: May 3, 2012 2 Cover: Map data plot for the port of Piraeus, Greece. Map data © OpenStreetMap contributors, CC-BY-SA. Copyright © 2010 by Ioannis F. Filippidis. All Rights Reserved. This work has been typeset by the author using XƎTEX & friends. Graphics which are not courtesy of the author reference the source in their caption. MATLAB® is a registered trademark of The Mathworks, Inc. OpenStreetMap is a registered trademark of Steve Coast. The OpenStreetMap logo is a registered trademark of the OpenStreetMap Foundation. Chapter 1 Usage 1.1 Introduction This is a small set of functions to import data from an OpenStreetMap XML Data File into MATLAB. The XML format is first loaded into MATLAB and then a parsing script extracts part of the information contained in the file. This is saved in a MATLAB structure. Then, it can be used to plot the transportation network and to extract its connectivity matrix, as well as to identify its unique nodes. An example of using these functions can be found in the file usage_example.m. The software architecture is shown in Fig. 1.1. 1.1.1 Dependencies This software requires the following functions, which can be downloaded from the Mathworks central File Exchange and are copyright of their authors, under the BSD license. 1. xml2struct file id 28518 ©2010 by Wouter Falkena. 2. lat_lon_proportions file id 32462 ©2011 by Jonathan Sullivan. 3. dijkstra file id 24134 ©2008-2009 Stanford University, by David F. Gleich. For the user’s convenience, these functions have also been included in the distribution of this software, together with their respective licenses. Remark: Please put these functions in your MATLAB path. You can do this by adding the xml2struct directory (after extracting from the archive) to your MATLAB path (pathtool command in MATLAB). 1.2 Parse the OpenStreetMap file To parse an OpenStreetMap XML file (OSM XML) use the function parse_openstreetmap, by issuing the command parsed_osm = parse_openstreetmap(openstreetmap_filename). This will parse an OSM XML file downloaded from the OpenStreetMap website. The OSM filename is provided as the string argument openstreetmap_filename. This function returns a MATLAB structure parsed_osm containing a subset of the OSM data sufficient to extract the transportation network connectivity. The structure’s fields are shown schematically in Fig. 1.3. To download an OpenStreetMap XML Data file, navigate to http://www.openstreetmap.org/ 4 Usage parse_openstreetmap.m load_osm_xml.m xml2struct.m (c) 2010, Wouter Falkena parse_osm.m show_map.m plot_way.m assign_from_parsed.m extract_connectivity.m get_way_tag_key.m get_unique_node_xy.m plot_road_network.m route_planner.m plot_route.m plot_nodes.m Figure 1.1: Software architecture. penStreetMap (a) OpenStreetMap logo (®by Steve Coast from the OpenStreetMap wiki). (b) Aerial photography for mapping the Praga district of Warsaw (CC BY-SA by Balrog, via OpenStreetMap wiki). Figure 1.2: OpenStreetMap (c) GPS Mapping of Strasbourg on bicycle. (CC BY-2.0 by francois, via Wikimedia Commons). 1.3 Plot the map 5 bounds node lat, lon, ... way nd, tag, ... .osm relation Figure 1.3: OpenStreetMap MATLAB structure fields. OpenStreetMap osm file 37.95 Latitude (o) 37.945 37.94 37.935 37.93 37.925 23.62 23.625 23.63 23.635 23.64 23.645 23.65 23.655 23.66 23.665 23.67 Longitude (o) (a) Without an underlying image. (b) With an underlying image. Figure 1.4: Examples of plotting the loaded OSM data using plot_way. Map data © OpenStreetMap contributors, CC-BY-SA. and after zooming in the area of interest, export its data using the Export option to save it as an OpenStreetMap XML Data file, selecting this from the Format to Export options. 1.3 Plot the map To plot the parsed OSM file, using the MATLAB structure obtained in the previous section, use the function plot_way(ax, parsed_osm, map_img_filename). Argument ax is a handle to an axes object. parsed_osm is the MATLAB structure object returned by the parsing function parse_openstreetmap. Optionally, the last argument, map_img_filename, is a (raster) picture to load and plot underneath the transportation network of the map. Examples of the result with and without the underlying image are shown in Fig. 1.4a and Fig. 1.4b, respectively. The other plotting functions are plot_nodes, plot_road_network and plot_route. Function plot_nodes can be used to plot selected (or all) nodes and optionally their IDs as text labels, as shown in Fig. 1.5c. Function plot_road_network plots the nodes and edges connecting them, as determined by the connectivity matrix created using extract_connectivity (see section 1.4), as shown in Fig. 1.5d. Function plot_route plots the series of nodes traversed along a route found by the route_planner function, as shown in Fig. 1.7a and Fig. 1.7b. 1.4 Extract road connectivity and Routing To extract the road connectivity from the OSM data loaded into the MATLAB structure, use the function extract_connectivity. This function extracts the connectivity of the road 6 Usage OpenStreetMap osm file 44.414 44.414 44.412 44.412 44.41 44.41 o Latitude ( ) Latitude (o) OpenStreetMap osm file 44.408 44.408 44.406 44.406 44.404 44.404 44.402 44.402 8.924 8.926 8.928 8.93 8.932 8.934 8.936 8.924 8.938 8.926 8.928 8.93 8.932 8.934 8.936 8.938 Longitude (o) Longitude (o) (a) plot_way without an underlying image. (b) plot_way with an underlying image. index=681 index=671 index=831 index=61 44.412 index=281 index=471 Latitude (o) 44.41 index=291 44.408 index=561 index=911 index=661 index=81 index=801 index=791 index=771 index=581 index=631 index=461 index=451 index=761 index=611 index=901 index=851 index=731 index=521 index=111 index=941 index=91 index=751 index=531 index=101 index=651 index=491 index=821 index=11 index=641 index=951 index=151 index=891 index=691 index=961 index=741 index=811 index=921 index=131 44.406 index=621 index=51 index=1 44.414 index=141 index=701 44.412 44.41 Latitude (o) 44.414 OpenStreetMap osm file OpenStreetMap osm file index=781 44.408 index=31 44.406 44.404 index=721 index=871 index=301 44.402 8.924 8.926 8.928 8.93 index=441 index=981 index=991 index=861 index=711 44.404 index=881 index=971 8.932 8.934 8.936 8.938 Longitude (o) 44.402 8.924 index=331 8.926 8.928 8.93 8.932 8.934 8.936 8.938 Longitude (o) (c) plot_nodes. index=71 (d) plot_road_network. Figure 1.5: Examples of plotting the loaded OSM data. Map data © OpenStreetMap contributors, CC-BY-SA. 1.4 Extract road connectivity and Routing 7 0 1000 2000 3000 4000 5000 6000 0 1000 2000 3000 4000 nz = 15204 5000 6000 Figure 1.6: Connectivity matrix of transportation network of Piraeus (nodes are not unique), corresponding to Fig. 1.4a. Observe the sparsity of the adjacency matrix. network of the OpenStreetMap file. This yields a set of nodes where the roads intersect. Some intersections may appear multiple times, because different roads may meet at the same intersection and because multiple directions are considered different roads. For this reason, in addition to the connectivity matrix, the unique nodes are also identified. To call it, issue the command: [connectivity_matrix, intersection_nodes] = extract_connectivity(parsed_osm). The input parsed_osm is the MATLAB structure returned by function parse_openstreetmap. This function returns the network’s adjacency matrix in connectivity_matrix and the unique nodes corresponding to the intersections of the network in intersection_nodes. Routing can be performed based on the extracted adjacency matrix. The function performing routing is route_planner. It can be called by issuing [route, dist] = route_planner(dg, start, target), where dg is the adjacency matrix of the directed graph representing the transportation network (that is, the connectivity_matrix above), start is the source node and target the destination node. This function returns route, which is a matrix of traversed node indices, and dist, which is the count of nodes traversed (and not the spatial distance over the map). Plotted examples are shown in Fig. 1.7a and Fig. 1.7b. 8 Usage OpenStreetMap osm file 44.414 44.414 44.412 44.412 44.41 44.41 o Latitude ( ) Latitude (o) OpenStreetMap osm file 44.408 44.408 44.406 44.406 44.404 44.404 44.402 44.402 8.924 8.926 8.928 8.93 8.932 8.934 8.936 8.938 Longitude (o) (a) Without an underlying image. 8.924 8.926 8.928 8.93 8.932 8.934 8.936 8.938 Longitude (o) (b) With an underlying image. Figure 1.7: Examples of route plotting using plot_route and plot_way. Map data © OpenStreetMap contributors, CC-BY-SA.
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File Type : PDF File Type Extension : pdf MIME Type : application/pdf PDF Version : 1.4 Linearized : No Page Mode : UseOutlines Page Layout : TwoPageRight Page Count : 8 Creator : LaTeX with hyperref package Title : OpenStreetMap Toolbox for MATLAB v.0.1 Subject : User Manual Author : Ioannis Filippidis, jfilippidis@gmail.com Producer : MiKTeX-xdvipdfmx (0.7.8) Keywords : OpenStreetMap, osm, MATLAB Create Date : 2012:05:03 17:48:07+02:00EXIF Metadata provided by EXIF.tools