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Map Warper

Mapwarper is an open source map geo-rectification, warping and georeferencing application. It enables a user to upload an image, a scanned map or aerial photo for example, and by placing control points on a reference map and the image, to warp it, to stretch it to fit.

Map Warper screenshot of main interface

The application can be seen in use at http://mapwarper.net for public use and in library setting at http://maps.nypl.org

The application is a web based crowdsourced geospatial project that enables people and organisations to collaboratively publish images of maps online and digitize and extract vector information from them.

Users rectify, warp or stretch images of historical maps with a reference basemap, assigning locations on image and map that line up with each other. Often these historical maps were in big paper books, and so for the first time they can be stitched together and shown as a whole, in digital format.

Users can crop around the maps, and join them together into mosaics (previously called layers).

By georeferencing the images, they can be warped or georectified to match the locations in space, and used in GIS software and other services. One such use of these warped maps is an application that that helps people digitize, that is, trace over the maps to extract information from them. For example, buildings in 18th Century Manhattan, details changing land use, building type etc. This application is called the Digitizer.

The application runs as a Ruby on Rails application using a number of open source geospatial libraries and technologies, including PostGIS, Mapserver, Geoserver, and GDAL tools.

The resulting maps can be exported as a PNG, GeoTIFF, WMS, Tiles, and KML for use in many different applications.

Groups of maps can be made into "mosaics" that will stictch together the composite map images.

Documentation Index

Features

  • Upload image by file or by URL
  • Find and search maps by geography
  • Adding control points to maps side by side
  • Crop maps
  • User commenting on maps
  • Align maps from similar
  • Create mosaics from groups of maps
  • Login via Github / Twitter / OpenStreetMap / Wikimedia Commons
  • OR signup with email and password
  • Export as GeoTiff, PNG, WMS, Tile, KML etc
  • Preview in Google Earth
  • User Groups
  • Map Favourites
  • Social media sharing
  • Bibliographic metatadata creation and export support
  • Multiple georectfication options
  • Keyboard shortcuts for map controls (save point etc)
  • Automagic placement of points based on transform
  • Import CSV of Control points to a map
  • Download CSV of control points
  • API
    • JSON API Specifications
  • Admin tools include
    • User statistics
    • Activity monitoring
    • User administration, disabling
    • Roles management (editor, developer, admin etc)
    • Batch Imports
  • Caching of WMS and Tile via Redis
  • i18n support
    • English
    • Dutch
    • Japanese

Ruby & Rails

  • Rails 4
  • Ruby 2.4

Database

  • Postgresql 8.4+
  • Postgis 1.5+

Installation Dependencies

It's probably better to install everything locally but you can look at the Dockerfile to get an idea of what to install. Alternatively you can use docker compose to get it running

Ubuntu 16.04 18.04 &

Mapwarper should work on Ubuntu 16.04 - however there are issues with the Ubuntu package of GDAL and potentially with Mapserver (if not using package Ruby, e.g. RVM)

GDAL needs to be compiled from source to ensure the gdal_rasterize bug is fixed. It should be installed locally and can exist with the package maintainers version. Then point to this newly compiled path in the application.yml file.

If rvm is being used, ruby mapscript for mapserver should be compiled from source, and then linked or installed into the path. You can use the ubuntu package rubymapscript along with the system rub (2.3.1) without worrying about this.

See ubuntu16_18_installnotes for some hints as to what to do.

Ubuntu 18 by default has changed the imagemagick policies, so you can open up some of the limits. See config/imagemagick-policy.xml

Configuration

Create and configure the following files

  • config/secrets.yml
  • config/database.yml
  • config/application.yml

In addition have a look in config/initializers/application_config.rb for some other paths and variables, and config/initializers/devise.rb for devise and omniauth

Database creation

Create a postgis database

psql mapwarper_development -c "create extension postgis;"

Database initialization

Creating a new super user

Run the rake task

rake warper:create_superuser

and make a note of the generated password.

Alternatively in the Rails console to do it by hand:

user = User.new
user.login = "super"
user.email = "super@example.com"
user.password = "your_password"
user.password_confirmation = "your_password"
user.save
user.confirmed_at = Time.now
user.save

role = Role.find_by_name('super user')
user = User.find_by_login('super')

permission  = Permission.new
permission.role = role
permission.user = user
permission.save

role = Role.find_by_name('administrator')
permission = Permission.new
permission.role = role
permission.user = user
permission.save

WMS/Tile Caching

To enable caching, install Redis and enable caching in the environment file. You may want to configure the redis.conf as appropriate to your server. For example turning off saving to disk and setting a memory value for LRU "maxmemory 2000mb" "maxmemory-policy allkeys-lru" keeps the redis server having 2gig and expires keys based on a least used algorithm.

Development

Probably better to install and run things locally but you can get things going with Docker with a Dockerfile and a docker-compose yaml file which will set up a database and redis images too.

API

See README_API.md for API details

License

MIT: see LICENSE

Note that Tilestache which is bundled in lib/, error_calculator.rb, SelectFeatureNoClick.js and helmerttransform.js and all are individually BSD licensed.