Other map related documentations

Country polygons and border items

The country polygon

The country polygon is the geometry for the land mass of a country (mainland and islands in the ocean). This should be as detailed as possible geometry-wise since it is used for displaying land areas in map images. It is represented by the mapGfx data of country overview maps (co-maps) and created from a mif file with the country geometry. The mif file contains ONE mif feature Region with many polygons. There is one mif file for each country overview map of each country, the name of the mif files(s) are the same as the names of the country overview map(s) followed by the suffix .mif. A very large country may have more than one country overview map, called e.g. germany_1 and germany 2, must have country polygon mif files named germany_1.mif and germany_2.mif. Both those country polygon mif files must have the exact same content, ideally let them be links to a file called germany.mif. The country polygon mif file(s) are stored in the genfiles country directory structure BASEGENFILESPATH/countries/{country}/countrypol

The country polygon is filtered in coordinate levels to define which geometry to draw for different zoom levels. To save time in the map generation process, it is possible to re-use a pre-filtered country polygon from a country overview map stored on disc. The map id of the co-map is not important, the map generation process uses the name of the co-map to find which co-map to re-use filtering from. The co-map(s) with pre-filtered country polygon are also stored in BASEGENFILESPATH/countries/{country}/countrypol

In map merges with several countries, each country polygon is filtered re-using filtering results from the neighbouring countries to avoid gaps on borders. To define where a border part should start and end we have a file which defines these break point coordinates. The break points file is located on disc BASEGENFILESPATH/countrypol/countryBorderBreakPoints.txt. The country polygon mif files must include the break point coordinates.

The country polygon must not overlap any water in the ocean, since water items with water type ocean and otherWaterElement are not included when drawing map images.

Create the country polygon

The country polygon can be created in a generic way by merging the geometry of all municipal items in one country.

  • Print municipals from mcm-maps using GenerateMapServer
    • ./GenerateMapServer --printMidMifMapGfx=FILENAME 00*.mcm
    • FILENAME = eg mun_norway
    • mun_norway.mid and mun_norway.mif are created
  • Use MifTool or ARcView or other GIS software to dissolve all municipals to one region.
  • Then you need to remove any ocean/coastal water that covers the land. Typically you need to remove all land that is covered by water with type otherWaterElement. You can print water items to midmif with GenerateMapServer --printMidMif option

Country borders and border items

Border items in mcm maps defines the borders between countries on land.

Help files

When generating country overview maps, a few files are used and or created for handling country borders and border items.

countryBorderBreakPoints.txt:

  • File containing coordinates defining start and end of common border parts between countries. Located in BASEGENFILESPATH/countrypol/

  • Use: identifying border parts for common country polygon filtering.

    703748538 136738514  swe-no-ocean
823915938 245139346  swe-no-fin
785357201 288128788  swe-fin-ocean
823841138 345148304  no-fin-russia

countryBorders.txt

  • key word: BORDERPART countryMapName
  • A list with all filtered parts of the polygon(s) from the country polygon that are split up by coordinates defined in countryBorderBreakPoints.txt. The key word line is followed by 3 identifying coordinates (start, end, onTheWay), one row with the number of coordinates in the filtered border part, and finally all filtered coordinates.

    • Use: common country polygon filtering and creation of borderItems.txt file.

      BORDERPART sweden (703748536,136738512) (823915936,245139344) (767435509,168669286) 2644 703748539 136738515 703741240 136735843 …

borderItems.txt:

  • key word: BORDERITEM borderPartNumber (from countryBorders.txt)
  • A list with all true borders = borders on land that exist between the countries included in a merge map generation. It is mapped to the countryBorders.txt by borderPartNumber.

  • Use: creating border items.

    BORDERITEM 1
 from (703748536,136738512)
 to   (823915936,245139344)
 via  (767435509,168669286)

Country borders

The first country in east world merge list is Sweden. The main polygon in the Swedish country polygon is split by 3 country border break points; the border to Norway, the border to Finland, and the coast. After generating the Swedish country overview map there are 3 BORDERPART keys in the countryBorders.txt file. The key word line is really made up of “BORDERPART sweden” meaning that the border part was written to countryBorders.txt when processing the co map named sweden.

The next country in EU merge list is Norway. The main polygon of the Norwegian country polygon is split by 5 break points; the border to Sweden, the border to Finland, the border to Russia, and then the coast is split in 2 pieces for faster filtering. When processing the Norwegian co map, the existing countryBorders.txt file is read, looking for any old border parts that fit the Norwegian parts. And, yes there is one. The Swedish part that is the border towards Norway exists already. The key word line says that the BORDERPART was written for co map sweden, and now when processing co map named norway this means that we have a true border = a border on land. This information is written into the borderItems.txt file. Key word is “BORDERITEM N” where N is the border part number. The identification coordinates are also written. When a border part is re-used like this, no further info is written into the countryBorders.txt file.

For a large country with many country overview maps, e.g. if Germany has 8 co maps. After the first co map germany_1 is processed, all German border parts exist in the countryBorders.txt file with key word BORDERPART germany_1. When processing the second German co map named germany_2, all border parts match the ones in the countryBorders.txt file, but nothing is written to the borderItems.txt file, since we have the same country. The test for “same country” is done with memMap between the country polygon mif files; germany_1.mif and germany_1.mif are exactly equal, norway.mif and sweden.mif are not.

Border items

When all country overview maps for all countries in the east world merge have been created, the border items are created looping all co-maps in the merge-directory. Again we start at the first co map: Sweden. The country polygon of the Swedish co map is loaded and border parts are re-identified using the country border break points file. For each border part, the borderItems.txt file is looped. When the identifying coordinates match the current border part, a border item is created with gfxData from the current border part.

Create the co-map with pre-filtered country polygon

If you needed to edit the country polygon geometry of a country that already has a pre-filtered country polygon stored in genfiles/country/countrypol, this is how to proceed. Follow these instructions to create new co-map(s) with the pre-filtered country polygon for a certain country. If borders between several countries were changed, you need to create new pre-filtering for all countries that share the changed borders.

  • Create a working directory and copy the new country polygon mif file(s)
  • Copy from the latest east/west world merge
    • The country overview map(s) of the country
    • The countryBorders.txt file
    • The borderItems.txt file (at least if you fix update country polygons directly in a merge)
  • Identify the BORDERPARTS of countryBorders.txt that will have a new geometry with the new mif file(s). Remove those border parts from the file. And remove them also from the borderItems.txt file.
  • Set a new mapGfxData of the country overview map(s) from the new mif file
    • MapTool --mapLab2=setNewMapGfx 080000003.mcm|& tee mt_setNewMapGfx_080000003.log
  • Filter the country overview map(s). It re-uses border parts from countryBorders.txt or creates new border parts if no match is found. * GenerateMapServer --filterCountryPolygon --coPolBreakPoints=fullPath/genfiles/countrypol/countryBorderBreakPoints.txt 080000003.mcm|& tee gms_filterCountryPolygon_080000003.log
  • Create the gfx filtering * GenerateMapServer --gfxFilteringOfCoPols 080000003.mcm |& tee gms_gfxFilteringOfCoPols_080000003.log
  • Fix border items * Remove the old border items: MapTool --removeitems=borderItems 080000003.mcm |& tee mt_rmBorders_080000003.log * Create new ones: GenerateMapServer --coPolBreakPoints=fullPath/genfiles/countrypol/countryBorderBreakPoints.txt --createBorderItems 080000003.mcm |& tee gms_createBorders_080000003.log

Done! Check in MapEditor that the mapGfxData has one geometry for every filter level. If only the coastal parts of the country polygon was updated you can check that the new mapGfxData is exactly the same as the border items.

Copy the country overview map(s) together with the new country polygon mif file to the countrypol directory on genfiles genfiles/countries/{country}/countrypol. So they match for next map generation.

If you did this hacking in an existing eastWorld or westWorld merge, you also need to

  • Update creation times
  • New index.db + m3 maps for the country overview maps
  • New search and route caches for the co maps

Filtering in map generation

The gfxData of mcm maps and items in the mcm maps need filtering to have a more simple graphical representation to display when zoomed out. Two different filterings are available for map generation.

  • A simple filtering that only removes unnecessary coordinates from the gfxData (coordinates on a string).
  • A level filtering that gives the gfxData a set of graphical representations to use for different zoom levels.

Filtering map items

GMSUtility::filterCoordinateLevels (level filtering)

Currently NOT used in map generation

This filtering in levels is done with GMSUtility::filterCoordinateLevels filtering items in the maps. After filtering the OldGenericMapHeader::m_mapFiltered is set to true. It can be included in map generation calling GenerateMapServer --filterCoordinates --filterLevels 000000000.mcm

Process:

  • The gfxData of the items are first filtered to get rid of coordinates on a string, with filter distances
    • area items 3 meters
    • line items 1 meters, but 50 meters in the country overview map
  • The gfxData of the items is updated. The coordinates which to display only on level 0 are removed, and the coords which to display on level 1 (after coords-on-string filtering) are kept.
  • The gfxData of the items is filtered again to get the 16 filtering levels. The filtering distances are fetched with the MapFilterUtil::getFiltDistanceForLineItem and MapFilterUtil::getFiltDistanceForAreaItem.

Only items of specified item types are filtered. Items of all other types have the coordinates of their gfxData altered to represent filter level 15. This means that they are displayed on all levels.

GMSUtility::filterCoordinates

Currently used in map generation in the final filtering step in the map generation process

Included in map generation when calling GenerateMapServer --filterCoordinates 000000000.mcm
Used with the purpose of removing coordinates on a string. Not using the filter levels in coordinates, instead the items are filtered only once.

  • First the GfxData::openPolygonFilter to get a reference path.
  • Then with GfxFilterUtil::filter to get the final result.

This method does not consider shared borders between neighbouring area items.

Filtering country overview map gfxData (the country polygon)

GMSUtility::filterCountryPolygonLevels (level filtering)

Currently used in map generation.

This filtering in levels is done with GMSUtility::filterCountryPolygonLevels filtering the map gfx data of country overview maps (country polygon). After filtering the OldGenericMapHeader::m_mapGfxDataFiltered is set to true. It is included in map generation when calling GenerateMapServer -X

  • processXMLData -> createCountryMaps -> createCountryMapBorder -> filterCoPolCoordinateLevels

If to test separately, called with GenerateMapServer --filterCountryPolygon 080000001.mcm

The filtering distances are fetched with the MapFilterUtil::getFiltDistanceForMapGfx method, and defined in the MapFilterUtil::m_mapGfxFilterDistances vector intiated in the MapFilterUtil::initMapGfxDistances method.

Needs to be combined with a file containing break points, which is a set of mc2 coordinates defining the corners of country polygons where they meet the country polygon of other countries. The country polygon gfxData is split in border parts based on the break points, end each border part is filtered individually. The filtering of the first country is then re-used when filtering the neighbour country, to get a shared border on all levels.

OldCountryOverviewMap::makeSimplifiedCountryGfx

Used in map generation. Included in map generation when calling GenerateMapServer -X

The country overview map has a Stack m_simplifiedGfxStac´ allocated to be [NBR_SIMPLIFIED_COUNTRY_GFX][m_nbrGfxPolygons]? . It is an array of stacks pointing to coordinate indexes to use for ? NBR_SIMPLIFIED_COUNTRY_GFX? pre-decided filterings (currently 7). This array is saved to and read from disc. Uncertain if this is used for any map images…

The array is created in OldCountryOverviewMap::makeSimplifiedCountryGfx based on some of the coordinate filter levels. Which levels to use in the array is defined in OldCountryOverviewMap::mapGfxFilterLevels.

Previous to the filter levels stored in coordinates, the simplified country gfx in makeSimplifiedCountryGfx was created with the GfxData::getSimplifiedPolygon method.

  • The filtering distances are decided in OldCountryOverviewMap::filtMaxDistance and OldCountryOverviewMap::filtMinDistance, where the min values are always 0.
  • This filtering method is fast when the max distance is a large value, slow when the max dist is a smaller value.

Walk-through of map generation process

Country generation with makemaps script

The makemaps script is used for generating individual countries. The script is located in the mc2 repo in Server/bin/Scripts/MapGen

Variables set in the makemaps script may be over-rided by options and/or by the variable file. Some variables controlling the script are only set in the variable file, see the Variable file section

For following the actions in the makemaps script, start reading from “Determine which side to drive on in the country”

Merge generation with makemaps.mcgen script

The makemaps.mcgen script is used for merge map generation and generation of multiple individual countries. The script is located in the mc2 repo in Server/bin/Scripts/MapGen.

Variables set in the makemaps.mcgen script may be overriden by options.

For following the actions in the makemaps.mcgen script, start reading from

  • “Generates single countries in” for multi generation of individual countries
  • “Merge map generation starts” for merge map generation

MapEditor

The MapEditor is a tool where you can examine the content of mcm maps. It shows you all items and attributes, how street segments and ferry lines are connected, etc. The MapEditor also allows you to edit attributes that are not correct, creating map correction records which can be added to the maps in the map generation to fix problems. The MapEditor is implemented using gtkmm2.4.

Start MapEditor from a terminal window with the mcm map to load in the tail, either the hex id of the mcm map (if in current directory) or the full path to the mcm map file name. Misc debug info will be printed in the terminal window while working in the MapEditor.

./MapEditor 1a
./MapEditor mcm/OSM_201005/dk_20100520_first/00000001a.mcm

The main MapEditorWindow has two parts; the map area to the left and the menue area to the right. In the top title bar the decimal ID and the name of the loaded mcm map is displayed, along with the map origin string (the map release with the long version of the map supplier string).

In the map area you zoom in with left mouse click and zoom out with right click. Middle mouse button click will select the closest displayed item. Decide which item types to display in the map in the map area with the “Drawsetting”-button from the menue area, or short command “d” with the MapEditorWindow active.

Close the MapEditor program by pressing the “Quit”-button in the menue area, or simply by short command “q”.

The menu area displays some info about the maps: the decimal map ID, the true creation time (when the map was created in the individual country generation), and time for latest WASPing (adding POIs from WASP database) and extradata time (adding map correction records from WASP database).

You can search for mcm item ID, item name (exact spelling, case sensitive) and POIS with certain WASP POI ID with the “Search for item with ID”. With the “Search for coordinate” you can search for just that, coordinate given in either wgs84 degrees or mc2 works.

When searching for an item in the menue area or middle-clicking in the map area selecting an item, an item info widget will open displaying info about the item, e.g. location in search index and all attributes. The selected item will also be highlighted with red color (if part of the displayed item types). For routeable items (street segments and ferry items) node attributes are listed by selecting one node (0 or 1), connections to each node from other routeable items’ nodes are listed when pressing the little arrow in front of the node (0 or 1). Selecting one connection will display the turn description and vehicle restrictions for the connection. A selected node is highlighted with a red square in the end of the routeable item it belongs to. A selected connection is also highlighted, orange-yellow square and line is the node and routeable item which the connection comes FROM, red square and line is the routeable item which the connection leads TO.

When one item selected, in the item info widget press:

  • the “Coords” button to get the coordinates of the selected item geometry printed in the terminal window
  • the “MidMif” button and the selected item is printed to item.mid and item.mif. The result is similar to the Wayfinder midmif format, but especially the routeable items will have different attributes.

You can load a text file with either mcm item ids or mc2 coordinates when you start the MapEditor with ‘’–highlightIDs=ITEMIDFILE’’ resp ‘’–highlightCoords=COORDINATEFILE’’ options. If you loose the highlight when clicking around in the map, press the “Re-highlight ids”-button and they are back. The format of the rows in the highlightIDs file: “itemID”. If you want to add special colors to the items the rows are “itemID color” (separated by space). You can choose from the colors defined in the MapEditor ‘‘MEGdkColors::color_t’’, e.g. purple1 or green3. Some of the colors are organized in the order of the rainbow, items highlighted with colors closer to purple are drawn before the items with colors closer to red. The format of the rows in the highlightCoords file: “mc2lat mc2lon” (separated by space).

It is possible to edit most attributes in the MapEditor to create map correction records (extradata records).

  • Example of correcting a mis-spelled name: Select the item which has the incorrect name. In the “Names”-part of the item info widget, select the mis-spelled name from the name list and press “Edit”. The “Edit Name” dialog will open. Enter the name spelled the correct way and press OK. NB that you must enter the names in latin-1 (ISO 8859-1) char encoding, since MapEditor converts all strings from latin-1 to UTF8 before adding it to the map. If you want to add a new name to the selected item, instead select the “–Add name–” entry and press “Edit”. Add the name and specify name type and language and press OK.
  • The correction records will be written to the file names in the “Extradata log filename” box, default name is “changelog.ext” if you do not change it to something else.
  • Pressing the “Delete”-button in the item info widget will remove the selected item.
  • Pressing the “OK”-button in the item info widget or name dialog will save the attribute changes and write records to the extradata file. The changes are applied on the mcm map locally loaded in MapEditor, but the mcm map on disc is not affected.
  • There is a “log comment box” in the item info widget and name dialog just above the OK-button. Fill the fields there if you want to have something special. Input must be in latin-1 (ISO 8859-1) char encoding.
  • Pressing the “Save”-button in the menue area, the mcm map will be saved to disc. The simple rule is AVOID doing this! There is a “are you sure?” dialog opening if you press the “Save”-button by mistake. To see the result of map correction records, it is better run a individual country second map generation, adding map corrections from the WASP database to the maps.

The “Show extradata”-button is used for browsing extradata files, with records extracted from the WASP database with ‘‘addED.pl -f extractED’’. It is typically used when migrating map correction records to a new map release.

The “Show nodes”-button is another analyze function that can be used for analyzing the result of changes in the method that calculates turn descriptions. Create input for the “Show nodes” with MapTool –compturns option.

The “Filter level” box and “Update”-button is for inspecting filtering of the country polygon = the map gfx data in the country overview maps. The country polygon is filtered in 16 levels (0-15), level 15 has the least number of coordinates, level 14 has all the coordinates of level 15 and some more, level 13 has all the coordinates of level 14 and some more, etc. Enter a level and press “update” to see how the different filterings look like. This only makes sense for the country polygon of country overview maps, no other items in any maps are filtered in levels like this.