March 19, 2012
New OSM License, Some Practical Implications And Gray Areas

Occasionally I make digital maps for customers based on OpenStreetMap data. Sometimes they request the maps in form of bitmaps, and sometimes they need a vector format like SVG or PDF in order to be able to edit the maps in Adobe Illustrator. Of course, the issue of license always pops up and often have to explain the stipulations of CC BY-SA 2.0 to them.

Soon OSM will switch to a new ODbL license. I have to admit I mostly stayed away from the numerous legal talks that were going on various OSM channels, simply because I feel much more productive coding than participating in endless strings of emails. But now that the new license is here, I need to get acquainted with it from the perspective of someone trying to make (some) living out of OSM data. “I’m not a lawyer” is the usual phrase you can see in OSM legal discussions, but waiting for one to give you some solid information is like waiting for Godot, so I’ll make judgements based on my own understanding and some common sense instead, and simplify things when I feel like it. If anyone objects, they can twitter me with their objections and I’ll try to correct things.

So let’s say a customer requests an SVG map of my home town and I decide to use OSM data for it. For the sake of simplicity the map will be based purely on OSM data, so no other sources. Let’s first look at some of the important definitions in ODbL (emphases are mine):

“Database” – A collection of material (the Contents) arranged in a systematic or methodical way and individually accessible by electronic or other means offered under the terms of this License.

“Derivative Database” – Means a database based upon the Database, and includes any translation, adaptation, arrangement, modification, or any other alteration of the Database or of a Substantial part of the Contents. This includes, but is not limited to, Extracting or Re-utilising the whole or a Substantial part of the Contents in a new Database.

“Contents” – The contents of this Database, which includes the information, independent works, or other material collected into the Database. For example, the contents of the Database could be factual data or works such as images, audiovisual material, text, or sounds.

“Produced Work” – a work (such as an image, audiovisual material, text, or sounds) resulting from using the whole or a Substantial part of the Contents (via a search or other query) from this Database, a Derivative Database, or this Database as part of a Collective Database.

“Substantial” – Means substantial in terms of quantity or quality or a combination of both. The repeated and systematic Extraction or Re-utilisation of insubstantial parts of the Contents may amount to the Extraction or Re-utilisation of a Substantial part of the Contents.

So the first open question: is an SVG map a Produced Work or a Derivative Database? Or both? SVG map is an XML file that contains projected geographical data (together with visual styling attributes). OSM XML file can safely said to be a database. If you say SVG is not a database, where do you draw the line? What about KML or GML files?

This question is important because of the next clause:

Access to Derivative Databases. If You Publicly Use a Derivative Database or a Produced Work from a Derivative Database, You must also offer to recipients of the Derivative Database or Produced Work a copy in a machine readable form of:

a. The entire Derivative Database; or

b. A file containing all of the alterations made to the Database or the method of making the alterations to the Database (such as an algorithm), including any additional Contents, that make up all the differences between the Database and the Derivative Database.

If the SVG map file is not considered a Derivative Database, then you have an option of supplying the original OSM data (OSM XML file, PBF file or even a database snapshot) together with the SVG file or providing a description of how you derived the Derivative Database.

On the other hand, I can argue that SVG is a Derivative Database because it is “arranged in a systematic or methodical way and individually accessible” and “includes any translation, adaptation, arrangement, modification, or any other alteration” of the original OSM data. So in that case simply publishing the SVG file (and only that file) would cover the license requirements.

I should note that the SVG map has to be released under the ODbL or a compatible license.

Now let’s go one step further. Let’s assume (as I do) SVG is a Derivative Database. What if I then generate a PNG bitmap (or a Web map, for that matter) from the SVG file using Adobe Illustrator and want to publish that, too? One could argue that a bitmap is a Produced Work and since we already published the Derivative Database that produced this Work, we are covered.

But what if I didn’t generate the Web map from the SVG, but used a tool like Mapnik or Maperitive and generated it directly from an OSM extract instead? Let’s say that for practical purposes I don’t want to publish 1 GB of OSM data and I choose to go down the path of describing the “method of making the alterations” I did to generate the bitmap. What are the options here?

  1. I could write a detailed description of steps I performed to generate the Web map. Osmosis, Mapnik with all the batch scripts etc. I could even post the source code of the program(s) I used.
  2. On the other hand, I could just describe the process in a sentence or two. I could also say I used a special filter in Photoshop.

I can partly understand the spirit of the “method” clause - to enable access to the interesting derivations of the original data. But I see several holes in the “method” definition:

  1. What if I produced the map by arranging a lot of the map elements manually, by hand? This is quite a common case when you have to place map labels in order to avoid label conflicts. How would I describe the “method” other than saying that I did it by hand? How would that help anyone?
  2. What if I used an expensive proprietary software (like Illustrator or Photoshop)? Or even a piece of code that I haven’t released to anyone else? In that case nobody else would be able to reproduce the method. Does the “Contents” cover source code as well? It doesn’t mention the source code explicitly. If it does, then that implies you can only use open source software with OSM data, which would be silly.
  3. What about complex algorithms? How detailed the description would have to be for someone to be able to reproduce the algorithm? I’ve tried reproducing various algorithms from long scientific articles and I can tell you it’s not an easy task even if you have a detailed description.

Frankly, I don’t see how the “method” clause could be enforced in practice.

(UPDATE: now that I thought about it once more, the clause only talks about describing the method of arriving to the Derivative Database and not to the Produced Work itself. So I could just say “I downloaded the OSM extract from Geofabrik” and that would be it.)

One final question: does extracting OSM data for a city amount to a “substantial part” of the original OSM database?

8:40pm  |   URL: http://tmblr.co/Zm5DjxIFGTGz
(Notes: 2)
  
Filed under: osm openstreetmap ODbL licensing 
October 19, 2011
Maperitive: 3D Export

The latest Maperitive beta (download it from here) now contains a new command called export-3d, which generates a 3D mesh using the digital elevation model and places the map texture on top of it. The 3D model is exported into a COLLADA format, which can be imported into various 3D programs (Google SketchUp is the one I mostly used, it’s free).

Quick How-To

The quickest/easiest way to generate a 3D export is to move the map to the area you’re interested in and simply select the Tools | Export To 3D menu command. Maperitive will then generate files in the output/Maperitive3D directory of your Maperitive installation. If you do not load your own OSM vector layer, Maperitive will use OSM tiles, the same ones used to show tne OSM web map.

NOTE: be careful to keep the map area fairly small, otherwise you’ll end up with a 3D model that you won’t be able to import into other software, especially if you don’t have a top-of-the-line computer at your disposal.

Importing Into SketchUp

After opening SketchUp, choose **File | Import…” menu command. NOTE: Before browsing for the file, click on the Options… button and make sure Validate COLLADA file is turned off:

Validation should be disabled because it makes importing unbearably slow, especially for larger models. After you’ve done this, browse to your generated Maperitive3D.dae file and open it.

Depending on the size of your model, you might have to wait for some time for the importing to finish. Sometimes I even have to resort to killing the SketchUp process and regenerating a simpler model.

Configuring SketchUp

After the model has been successfully imported, you may want to tweak a few settings in SketchUp to make the rendering look better:

  • View | Edge Style | Edge - uncheck this so the edges of surfaces are not shown.
  • View | Face Style - choose Shaded With Textures to get the best effect.
  • View | Shadows - check this to turn on the sun shadows.

Tweaking The 3D Model

export-3d command provides additional parameters we can tweak. Type in help-command export-3d into the command prompt and you’ll get the list of those parameters:

COMMAND NAME: export-3d 
DESCRIPTION: generates a 3D map from the current map view and saves it to the disk 
PARAMETERS: 
  output-dir=<the directory where output files will be saved> (text, optional)
  mesh-points=<the maximum number of points the terrain TIM mesh should have> (integer, optional)
  tin-error=<the maximum allowed elevation difference (in meters) when simplifying the terrain TIN mesh (default is 1 meter)> (real number, optional)
  width=<bitmap width> (value, optional)
  height=<bitmap height> (value, optional)
  map-scale=<map scale to use when exporting> (value, optional)
  scale=<graphics scale to use when exporting> (value, optional)
  dpi=<DPI to use when exporting> (value, optional)
  zoom=<zoom level to use when exporting> (value, optional)

Better Bitmap Texture

By setting various bitmap parameters you can increase the resolution of the bitmap and/or the zoom level of the underlying OSM bitmap.

TIN Tweaks

To increase performance, Maperitive uses Garland-Heckbert’s TIN simplification algorithm to simplify the terrain triangulated irregular network (TIN). There are two command parameters that affect the simplification process:

  • tin-error: this is the maximum error (tolerance) allowed between the actual DEM elevation and the generated model, in meters. The default value is 1 meter and if your model becomes too big to handle, I suggest increasing the tolerance value.

  • mesh-points: this is the maximum number of points (vertices) the TIN should have. The simplification algorithm starts from a very simple model (just two triangles) and incrementally adds new points to it. Upon reaching the maximum number of points, the algorithm stops (regardless of the tin-error setting). This is a safeguard against the model going wild with too many points. So I suggest experimenting with those two values to get something workable for your case.

Setting The Map Area More Precisely

Instead of relying on the map window to act as your area of interest, you can specify printing bounds (right click on the map) and move them to an exact position of your choice.

Final Notes

This 3D export function is by no means of the same quality as some other OSM 3D projects - you don’t get any 3D objects apart from the terrain model, so don’t expect to see any 3D buildings, trees etc. It is, however, a very simple tool to use (I hope) and it produces an output in a fairly open standard (COLLADA) which can then be tweaked with other software.

The next logical step would be to include the things like roads and buildings as actual 3D objects, but I will leave that for the future since my task list already very full with other features.

Please send me feedback if you find this feature useful (or indeed if you find it crappy). Since all this is beta, expect to find bugs. Also, if you’re more of an expert in 3D field than me, a question for you: can you recommend any (preferably free) tool for raytracing which can consume COLLADA files generated by Maperitive?

2:24pm  |   URL: http://tmblr.co/Zm5DjxAsTOSS
(Notes: 58)
  
Filed under: 3D Maperitive cartography openstr openstreetmap osm Maperitive beta 
October 11, 2011
Maperitive: maperipy Progress

WARNING: this is one of those teaser-posts - you get to hear about the cool new features, but you won’t be able to try them out, at least not very soon.

Introduction

In the last few weeks since the beta release I’ve been working on a custom job involving Maperitive. I won’t go into details about the job itself, but the important thing is that this job was an opportunity for maperipy Python API to be extended with some new features. I’ll go through some of them, together with sample Python code.

Geometries

maperipy provides classes for basic geometries (compatible with OGC’s Simple Features Specification) like Point, LineString, LinearRing, Polygon, MultiPolygon etc. I’ve tried to stick to the syntax and semantics used by shapely library (unfortunately shapely itself cannot be used directly because it won’t run in IronPython - it depends on some C code in the backstage, but more about this some other time).

Custom Layers

maperipy now allows users to create their own custom map layers which can be programmatically filled with map symbols using geometries described previously:

# we first create a custom layer on a map
layer = map.add_custom_layer()

# create a simple geometry
line = LineString([(0, 0), (0, 10), (10, 10), (10, 0)])

# add a symbol for it...
symbol = LineSymbol("my_line", (line, ))
# ... and define the visual style
symbol.pen_width = 5
symbol.pen_color = Color("red")

# now we add the symbol to the layer
layer.add_symbol(layer)

Shapefiles

The custom job required the data to be loaded from shapefiles and then rendered on a map based on geometry attributes. This can now be achieved in maperipy:

# first we read the shapefile...
land_use = store.load_shapefile(r"LandUse.shp")

# ... and add polygons for a specific land use type
symbol = PolygonSymbol(
    "forest", 
    land_use.find_polygons(lambda p : p["land_use_type"] == 4000))
symbol.style.fill_color = symbol.style.pen_color = Color("green")
layer.add_symbol(symbol)

Rasters

maperipy supports several types of raster grid file formats: SRTM HGT, ESRI ASCII grid and XYZ. They can now all be used to generate hillshadings or relief contours.

Example code which reads a set of XYZ files, merges them together and then generates hillshading image from them:

parts = []

dem_dir = r"DEM"

for file_name in os.listdir(dem_dir):
    grid = store.load_xyz_grid (os.path.join (dem_dir, file_name))
    parts.append(grid)

whole_dem = Raster.merge(parts)

hillshader = IgorHillshader()

hillshadingBitmap = HillShadingProcessor.shade(whole_dem, hillshader, Color("black"), 1)
hillshadingBitmap.save("dem.png")

Spatial References

One of the biggest pieces of coding I had to do was to introduce SRIDs into the picture. This allows consuming of data sources which use spatial reference systems different from the WGS 84 lon/lat used by OSM. The next step will be to actually support different SRS-es, including different coordinate systems and different map projections.

When?

This is all very nice, but when will you get to use it? Well, maperipy needs a lot more work (what I’ve shown here is just a start!) and so does the main Maperitive code. I also need to write some documentation about the API. So my guesstimate would be a couple of months. Given that a lot of new functionality has been introduced since the last “official” release, I’m thinking of naming the next major release as “Maperitive 2.0” and this will include all the stuff introduced in the September beta release.

8:45am  |   URL: http://tmblr.co/Zm5DjxAY7L4W
(Notes: 4)
  
Filed under: Maperitive osm openstreetmap Python maperipy 
September 21, 2011
Maperitive Beta Update

DOWNLOAD LINK: http://maperitive.net/beta/Maperitive-1.1.2001.zip

I’ve just released an update of the Maperitive beta (it’s the same download link and build number).

This update has a few nasty bugs fixed and a couple of new features.

Label Collision Detection

Maperitive now detects if two or more labels overlap. In case of overlaps the label with lower priority is removed. Priority is determined by the order of the features and rules in the rules file - rules near the beginning of the file have a higher priority than the ones near the end.

A sample rendering of UK cities and towns (the first image is from the old Maperitive and the second was generated using the latest beta):

This is a very simple system and it covers only horizontal labels (so street names can still overlap). A better system will be implemented in the future.

TileJSON

generate-tiles command now generates an accompanying TileJSON file. TileJSON is an invention of MapBox developers and it is used to hold some basic information about the generated tiles, like:

  • map name, description and attribution,
  • minimum and maximum zoom,
  • map boundaries.

The benefit of this file is that certain JavaScript mapping libraries (like Wax) can read it and automatically configure themselves based on its data. Compare that to the last step in my web map tutorial where you needed to do it manually.

Here’s a sample TileJSON file generated by Maperitive:

// Generated by Maperitive v1.1.2001
// For more information about TileJSON format, visit https://github.com/mapbox/tilejson#readme
// TODO: Update the 'tiles' to reflect your actual path on the Web server
// TODO: Update the default map location (longitude, latitude, zoom)
{
    "tilejson":"1.0.0", 
    "name":"Maperitive Web Map", 
    "description":"Maperitive Web Map", 
    "attribution":"Map data © OpenStreetMap (and) contributors, CC-BY-SA", 
    "tiles":
    [
            "tiles/{z}/{x}/{y}.png"
    ], 
    "minzoom":9, 
    "maxzoom":13, 
    "bounds":
    [
        -1.2254669867114432, 
        51.041883339771708, 
        1.5044914337393456, 
        52.076449581817052
    ], 
    "center":
    [
        0.13951222351395121, 
        51.55916646079438, 
        9
    ]
}

Note the “TODO”s: make sure you have the proper values before uploading the file to your web server.

UPDATE: there was a bug in the generated TileJSON files, “tiles” is actually an array (thanks to @kkaefer for pointing this out). I’ve updated the beta release.

10:34pm  |   URL: http://tmblr.co/Zm5Djx9nI0IM
(Notes: 12)
  
Filed under: Maperitive algorithms openstreetmap osm Maperitive beta 
September 18, 2011
New Maperitive Beta Release

DOWNLOAD LINK: http://maperitive.net/beta/Maperitive-1.1.2001.zip

A new release of Maperitive (branded as build 2001) is finally here - albeit in beta form. I wanted to release the new stuff I was working on since May, but I didn’t want to wait for everything to be totally finished. But let’s start with some…

Notes about this release you should be aware of

NOTE 1: This beta release will not appear as an update when running the “standard” Maperitive release. It will also not be possible to later auto-update it with a new release when it arrives. I’m working on a revamped auto-updating system and the old updating mechanism has been turned off in beta (that’s why it’s beta). So you will have to download the beta manually, unzip it somewhere, and run Maperitive.exe (on Windows) or Maperitive.sh (on Linux/Mac). I do not recommend overwriting the previous installation, so keep that as your backup.

NOTE 2: there have been some changes in certain Maperitive script commands, so you may need to update your scripts. The changes are mostly in how the bounds are specified when exporting bitmaps or SVGs. More on that later.

NOTE 3: there wasn’t any major bug fixing done for this release. You can see the list of open bugs (it’s not the full list, some old bugs are reported in other places - I will migrate/fix those soon).

NOTE 4: the new GUI features like map elements selection and editing may be a little bit buggy. A lot of time has been invested in making them work as there were some fundamental problems that needed to be solved. Users running Maperitive on Linux/Mac may especially notice certain problems, due to the fact that Maperitive is running through Mono. In any case, please report any problems if you see them and I will do my best to fix them.

New Features

First let me say there aren’t any revolutionary new features in this beta. Most of the work I did was done on the infrastructure code, which will help me introduce cool new things in next releases.

What is new is the way how bounds are specified (bounds specify the geographical extents of Maperitive commands). Up until now, there was only one bounds parameter, but from now on you have geometry bounds and printing bounds.

Geometry Bounds

These are more or less the “old” bounds - you use them to specify the map area to download OSM data for (as an example). Geometry bounds are defined in terms of “min longitude, min latitude, max longitude, max latitude” coordinates. They are shown as a red rectangle with diagonal hatching (see the screenshot above).

Maperitive commands that act on geometry bounds have been renamed to dump-geo-bounds, geo-bounds-use-source, reset-geo-bounds, set-geo-bounds. I haven’t updated the Maperitive documentation for these yet, but you can still use help-command to get the list of supported arguments, like:

help-commands set-geo-bounds

Printing Bounds

Printing bounds are used by export-bitmap and export-svg commands to control the exported map area. What is cool about the printing bounds is that you can specify them in terms of paper size, paper orientation, paper margins, map scale and DPI resolution. This was one of the most requested features - to be able to export a map in terms of physical paper dimensions.

Printing bounds work in two modes: fixed paper mode and free-size mode. In free-size mode you are not bound to a particular paper size, so you can define the bounds in the old way (just like geometry bounds).

Printing bounds are shown as blue dashed rectangle:

New printing bounds commands are set-print-bounds-geo, set-print-bounds-paper and set-print-bounds-view. There is also a new command for setting the paper properties: set-paper.

Why Two Boundary Types?

It may seem a bit complicated two introduce two types of boundaries, but it is necessary precondition for me to be able to introduce map rotation in Maperitive (and support for different map projections). Why? Because once you rotate the map, the geometry bounds rotate, too, so they are useless for any kind of printing boundaries (which need to be rectangles parallel with the screen).

Editing Bounds Visually

There is no need to specify bounds using the command line interface, because there are a couple of new GUI features (which gave me the greatest headache). More on that follows.

Map Context Menu

Yes, the map now has a context menu (finally). So if you want to specify printing bounds, simply right-click on the map and choose Place Printing Bounds Here. Now you have printing bounds placed on the map and selected…

Selecting And Manipulating Map Elements

If you click on the geometry or printing bounds, you can select them - small yellow selection handles appear. You can drag the handles to resize the bounds. If you hold the Shift key, the resizing will maintain the aspect ratio. Hold the Control key and you will be able to resize while maintaining the center point.

Move the mouse a little bit more inside the bounds box and you will be able to move the whole bounds across the map.

Properties Window

The last major new GUI “thingy” is the Properties window. If you right-click on the printing bounds and choose Properties, a tool window will appear that lets you edit the properties. This means you don’t need to mess with command line to specify the paper size, for example.

What Comes Next

As I’ve already mentioned, Maperitive is getting a new updating system. The next “official” release will start using semantic versioning, like 2.4.2 and the old build numbering will be consigned to history. This will enable a more transparent updating system - users will be able to choose whether they want to install unstable releases or wait for the next stable/tested one.

Of course, I plan to fix some bugs too (including the ones that I’m sure you’ll report for this beta release).

Next major features: a better labeling mechanism (collision and duplicates detection, abbreviations…) and maperipy, the Python API and integrated Python scripting.

That’s really. I hope you’ll try the new beta and enjoy it. And don’t hesitate to send me your feedback (positive and/or negative)!

8:15pm  |   URL: http://tmblr.co/Zm5Djx9fwyAm
(Notes: 6)
  
Filed under: Maperitive car cartography openstreetmap osm Maperitive beta 
September 13, 2011
maperipy: Maperitive API for Python - A First Glimpse

A few days ago I started implementing maperipy, a Maperitive API for Python. It turns out to be a quite uncomplicated thing to do, compared to all infrastructure stuff I’m working on for the next Maperitive release, so it’s a kind of a relaxation between all the hard work.

The API is still very young and unsophisticated, but I’m very excited about it, because it could provide a whole new dimension of functionality to Maperitive users.

Here’s a simple Python script that clears the map and then adds a custom Web map to it (with custom copyright text):

from maperipy import MapLayer

map.clear_map();
layer = map.add_web_map_custom(
        "my hiking map", 
        ["http://beta1234.com.sunflower.arvixe.com/maps/tiles"])
layer.copyright = "it's made by me"
layer.opacity = 0.75

Another one, which scrolls the map along the X-axis:

from maperipy import MapPosition
import time

pos = map.position;

for n in range(10):
    map.position = MapPosition(15 + n/10.0, pos.y, 11)
    app.refresh_map()
    time.sleep(0.3)

First versions of maperipy will probably be available after I finish the work on the next major release of Maperitive. Hopefully some time in October.

5:10pm  |   URL: http://tmblr.co/Zm5Djx9Tu7kf
(Notes: 1)
  
Filed under: Maperitive maperipy openstreetmap osm python 
September 8, 2011
Maperitive Tutorial: Generating OSM Map For Adobe Illustrator In Seven Easy Steps

In this tutorial you will learn how to produce a vector map based on OpenStreetMap data and then export it to SVG format suitable for editing in Adobe Illustrator. SVG export is one of the most useful features Maperitive provides and I’ve spent a lot of time tweaking the code so that Illustrator can handle the exported SVGs.

NOTE: the tutorial has been written for Maperitive build 1228. Some things will change in the near future, so please visit http://maperitive.net for any updates.

First things first: start Maperitive (if you don’t already have it, you can download it from here). Unzip the package somewhere on your disk and run Maperitive.exe (on Windows) or Maperitive.sh (on Linux/Mac).

Step 1: Setting Your Map Limits

Currently Maperitive uses your computer’s memory to store map data, so there is a limit of how large a map it can work on. Because of that, we need to tell Maperitive what area we’re interested in, so all the operations will limit themselves on that area.

There are several ways to set the limits. The easiest is to move the map to the area, zoom in our out appropriately to cover all the area you want, and then use the Map / Set Bounds menu function.

I will do this manually by entering a following command in the command prompt (at the bottom of the screen):

bounds-set -74.03,40.7,-73.96,40.72

I suggest you do the same for the purposes of this tutorial, so our map areas would match. The area in question is lower end of Manhattan.

Step 2: Loading OSM Data

Now we need to get the vector OSM data for our map. There are several ways of doing this.

The easiest one is to use the Map / Download OSM Data menu function, which contacts an OSM server to fetch the data. Try it out. If it fails, try it a couple more times. The problem is that these servers are sometimes overloaded and unresponsive.

If this doesn’t work, another option is to use JOSM or the Export tab on the OSM Web Map site. In that case you will get an OSM XML file, which you need to save on your disk (using .osm extension!) and then load into Maperitive using the File / Open Map Sources menu function (or simply drag and drop the file into Maperitive).

Once the OSM data is in, we can proceed with the next step…

Step 3: Removing The Web Map

Now that we have some vector content of our own, we don’t really need the OSM web map anymore. Select the Web Map (OSM Mapnik) in the Map Sources window at the bottom of the screen and then click on the “X” button to remove it:

Step 4: Changing The Map Style

The default map style resembles the standard OSM Web map layer (generated using Mapnik). But just to show off, we will switch to something that looks like Google Maps. Choose Map / Switch To Rules / googlemaps menu function. After a second or two of processing, the map will change its style.

Step 5: Deciding The Map Scale

Depending on your needs, you can export the map using different map scales. Map scale is directly linked to the zoom level and together they determine what type of content is visible on the map and how the content is rendered. In the case of our Google Maps-like style, the street names are starting to appear on zoom level 15 and higher, so if you need them in your export, you will have to use the zoom level 15 or higher.

The zoom level value is displayed at the bottom of the screen:

The map scale is shown at the bottom left of the map itself, together with the bar scale indicator:

For this tutorial I’ve decided the zoom level 16 is the one I want. Try it out, you can set your own later.

Step 6: Exporting To SVG

The easiest way to export would be to use Tools / Export to SVG (For Adobe Illustrator) menu function. But since we need to specify the zoom level in our case, we will type the export-svg command manually into the Command Prompt:

export-svg compatibility=illustrator zoom=16

We instructed Maperitive to export the current map to a SVG file suitable for Adobe Illustrator and to use zoom level 16. After a couple of seconds a new file called output.svg should appear under the output directory of your Maperitive installation.

Step 7: Import Into Adobe Illustrator

Now that you have a SVG file, open up your AI and import it. If it complains about “roundtrips to Tiny”, simply ignore that.

Adobe Illustrator vs. Inkscape

You may wonder why you had to specify the compatibility=illustrator argument in the Step 6. I will just quote Maperitive documentation on this:

Due to the pretty buggy support which Adobe Illustrator provides for loading SVG files, it is not possible to have the same SVG optimally shown in both Illustrator and Inkscape. In other words, if you plan to use the SVG file in Illustrator, you should specify compatibility=illustrator parameter. Maperitive will in this case do some tweaks to the SVG file which allow it to be shown without any problems in Illustrator (tested in CS5). But do not expect this file to be usable in other SVG viewers/editors.

On the other hand, if you need a SVG file which can be shown in various Web browsers and editable in Inkscape, you should specify compatibility=inkscape parameter. Again, do not expect this file to be usable in Illustrator.

Conclusion

This tutorial shows only the basic workflow, but there are many ways of how the workflow can be customized and even automated (by putting everything into a Maperitive script). Visit http://maperitive.net for more information.

Good luck and enjoy mapping!

5:57am  |   URL: http://tmblr.co/Zm5Djx9Gv52F
(Notes: 90)
  
Filed under: Maperitive cartography osm openstreetmap tutorial GIS SVG Adobe Illustrator 
April 10, 2011
No, It’s Not Google Earth

It’s Maperitive with the new MapQuest OpenAerial map layer, actually. Cooming soon.

10:46am  |   URL: http://tmblr.co/Zm5Djx4BeG0Q
Filed under: Maperitive openstreetmap osm cartography 
April 2, 2011
Maperitive: Python Scripting Introduction

The upcoming release of Maperitive comes with a new and exciting feature: Python scripting.

What I’ll describe here is just an initial introduction of Python into Maperitive and right now is more of an experimental nature. I have great plans with Python, but there is still a lot of work to do and I wanted to release something to users so they can test it out and give some feedback.

Writing Python Functions

In the new release Python scripting can be used to define text labels. Let me give you an example with a piece of Python code:

def cycleLabel(e):
    str_list = []
    for set in e.tagSets:
        if set.hasTag('ref'):
            str_list.append(set['ref'])

    str_list.sort()
    return '+'.join(str_list)

So what does this code do? I won’t go into Python syntax (since I think it’s not that hard to understand for anyone with a little bit of programming inclination), but I’ll explain some basics.

We wrote a nice little function called cycleLabel which receives a map element (e) as an input argument. The function goes through the list of element tags and looks for ref tags, which it then puts into a list. The list is then sorted and transformed into a single string using the plus sign as a delimiter.

The above function can be used to render cycle route names. In OSM these are usually represented using cycle relations. Each route has its own relation, but several routes can share the same OSM way, so we need a way to show all the route names in a single label for that way. This is where the cycleLabel function comes into play.

A name of a route is stored in the ref tag and we collect all ref tags to be able to show them as a single label:

Using Python Code

Once we have our labeling function, we need to tell Maperitive to use it. Here’s an excerpt of rendering rules I used to produce the above map:

import-script:test.py

features
    lines
        cycle route : osmnetwork[type=route]
    ...     
rules
    target : cycle route
        define
            line-width : 3
            line-color : red
        draw : line
        define
            text-func : cycleLabel(e)
        draw : text

The important things are:

  • import-script tells Maperitive to load a Python source file
  • text-func is a new rendering property which you can use to call a Python function to prepare the text label.

In the next post we’ll go through element variable attributes which can be used in Python code to access various properties of the element.

6:30pm  |   URL: http://tmblr.co/Zm5Djx3-U7xY
(Notes: 2)
  
Filed under: Maperitive osm openstreetmap Python cartography 
March 30, 2011
Fill Textures In Maperitive

Playing with fill textures in #Maperitive. Just some random forest noise:

Coming up in the next release…

9:23pm  |   URL: http://tmblr.co/Zm5Djx3x9r2L
Filed under: Maperitive osm openstreetmap cartography maps 
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