Installation and configuration

Download Enhydris

Download Enhydris from https://github.com/openmeteo/enhydris/ (if you are uncomfortable with git and github, click on the “Download ZIP” button).

Prerequisites

Prerequisite Version
Python 2.6 [1]
PostgreSQL [2]
PostGIS 1.4 [3]
GDAL 1.9
psycopg2 2.2 [4]
setuptools 0.6 [5]
pip 1.1 [5]
PIL with freetype 1.1.7 [6]
Dickinson 0.1.0 [7]
The Python modules listed in requirements.txt See file

Note for production installations

These prerequisites are for development installations. For production installations you also need a web server.

[1] Enhydris runs on Python 2.6 and 2.7. It should also run on any later 2.x version. Enhydris does not run on Python 3.

[2] Enhydris should run on all supported PostgreSQL versions. In order to avoid possible incompatibilities with psycopg2, it is better to use the version prepackaged by your operating system when running on GNU/Linux, and to use the latest PostgreSQL version when running on Windows. If there is a problem with your version of PostgreSQL, email us and we’ll check if it is easy to fix.

[3] Except for PostGIS, more libraries, namely geos and proj, are needed; however, you probably not need to worry about that, because in most GNU/Linux distributions PostGIS has a dependency on them and therefore they will be installed automatically, whereas in Windows the installation file of PostGIS includes them. Enhydris is known to run on PostGIS 1.4 and 1.5. It probably can run on later versions as well. It is not known whether it can run on earlier versions.

[4] psycopg2 is listed in requirements.txt together with the other Python modules. However, in contrast to them, it can be tricky to install (because it needs compilation and has a dependency on PostgreSQL client libraries), and it is therefore usually better to not leave its installation to pip. It’s better to install a prepackaged version for your operating system.

[5] setuptools and pip are needed in order to install the rest of the Python modules; Enhydris does not actually need it.

[6] PIL is not directly required by Enhydris, but by other python modules required my Enhydris. In theory, installing the requirements listed in requirements.txt will indirectly result in pip installing it. However, it can be tricky to install, and it may be better to not leave its installation to pip; it’s better to install a prepackaged version for your operating system. It must be compiled with libfreetype support. This is common in Linux distributions. In Windows, however, the official packages are not thus compiled. One solution is to get the unofficial version from http://www.lfd.uci.edu/~gohlke/pythonlibs/. If there is any difficulty, Pillow might work instead of PIL.

[7] Dickinson is not required directly by Enhydris, but by pthelma, which is required by Enhydris and is listed in requirements.txt.

Example: Installing prerequisites on Debian/Ubuntu

These instructions are for Debian wheezy. For Ubuntu they are similar, except that the postgis package version may be different:

aptitude install python postgresql postgis postgresql-9.1-postgis \
    python-psycopg2 python-setuptools git python-pip python-imaging \
    python-gdal

# Install Dickinson
cd /tmp
wget https://github.com/openmeteo/dickinson/archive/0.1.0.tar.gz
tar xzf 0.1.0.tar.gz
cd dickinson-0.1.0
./configure
make
sudo make install

pip install -r requirements.txt

It is a good idea to use a virtualenv before running the last command, but you are on your own with that, sorry.

Example: Installing prerequisites on Windows

Important

We don’t support Enhydris very well on Windows. We do provide instructions, and we do fix bugs, but honestly we can’t install it; we get an error message related to “geos” at some point. Some people have had success by installing Enhydris using OSGeo4W, but we haven’t tried it. So, if you face installation problems, we won’t be able to help (unless you provide funding).

Also note that we don’t think Enhydris on Windows can easily run on 64-bit Python or 64-bit PostgreSQL; the 32-bit versions of everything should be installed. This is because some prerequisites are not available for Windows in 64-bit versions, or they may be difficult to install. Such dependencies are PostGIS and some Python packages.

That said, we provide instructions below on how it should (in theory) be installed. If you choose to use OSGeo4W, some things will be different - you are on your own anyway.

Download and install the latest Python 2.x version from http://python.org/ (use the Windows Installer package).

Add the Python installation directory (such as C:\Python27) and its Scripts subdirectory (such as C:\Python27\Scripts) to the system path (right-click on My Computer, Properties, Advanced, Environment variables, under “System variables” double-click on Path, and add the two new directory names at the end, using semicolon to delimit them).

Download and install an appropriate PostgreSQL version from http://postgresql.org/ (use a binary Windows installer). Important: at some time the installer will create an operating system user and ask you to define a password for that user; keep the password; you will need it later.

Go to Start, All programs, PostgreSQL, Application Stack Builder, select your PostgreSQL installation on the first screen, then, on the application selection screen, select Spatial Extensions, PostGIS. Allow it to install (you don’t need to create a spatial database at this stage).

Download and install psycopg2 for Windows from http://www.stickpeople.com/projects/python/win-psycopg/.

Download and install setuptools from http://pypi.python.org/pypi/setuptools (you probably need to go to http://pypi.python.org/pypi/setuptools#files and pick the .exe file that corresponds to your Python version).

Download and install PIL from http://www.lfd.uci.edu/~gohlke/pythonlibs/.

Download the latest dickinson DLL from http://openmeteo.org/downloads/ and put it in C:\Windows\System32\dickinson.dll.

Finally, open a Command Prompt and give the following commands inside the downloaded and unpacked enhydris directory:

easy_install pip
pip install -r requirements.txt

Creating a spatially enabled database

You need to create a database user and a spatially enabled database (we use enhydris_user and enhydris_db in the examples below). Enhydris will be connecting to the database as that user. The user should not be a super user, not be allowed to create databases, and not be allowed to create more users.

GNU example

First, you need to create a spatially enabled database template. For PostGIS 2.0 or later (for earlier version refer to the GeoDjango instructions):

sudo -u postgres -s
createdb template_postgis
psql -d template_postgis -c "CREATE EXTENSION postgis;"
psql -d template_postgis -c \
   "UPDATE pg_database SET datistemplate='true' \
   WHERE datname='template_postgis';"
exit

The create the database:

sudo -u postgres -s
createuser --pwprompt enhydris_user
createdb --template template_postgis --owner enhydris_user \
   enhydris_db
exit

You may also need to edit your pg_hba.conf file as needed (under /var/lib/pgsql/data/ or /etc/postgresql/8.x/main/, depending on your system). The chapter on client authentication of the PostgreSQL manual explains this in detail. A simple setup is to authenticate with username and password, in which case you should add or modify the following lines in pg_hba.conf:

local   all         all                               md5
host    all         all         127.0.0.1/32          md5
host    all         all         ::1/128               md5

Restart the server to read the new pg_hba.conf configuration. For example, in Ubuntu:

service postgresql restart

Windows example

Assuming PostgreSQL is installed at the default location, run these at a command prompt:

cd C:\Program Files\PostgreSQL\9.0\bin
createdb template_postgis
psql -d template_postgis -c "CREATE EXTENSION postgis;"
psql -d template_postgis -c "UPDATE pg_database SET datistemplate='true'
   WHERE datname='template_postgis';"
createuser -U postgres --pwprompt enhydris_user
createdb --template template_postgis --owner enhydris_user enhydris_db

At some point, these commands will ask you for the password of the operating system user.

Configuring Enhydris

In the directory enhydris/settings, copy the file example.py to local.py. Open local.py in an editor and make the following changes:

  • Set ADMINS to a list of admins (the administrators will get all enhydris exceptions by mail and also all user emails, as generated by the contact application).
  • Under DATABASES, set NAME to the name of the database, and USER and PASSWORD according to the user created above.

Initializing the database

In order to initialize your database and create the necessary database tables for Enhydris to run, run the following commands inside the enhydris directory:

python manage.py syncdb --settings=enhydris.settings.local --noinput
python manage.py migrate --settings=enhydris.settings.local dbsync
python manage.py migrate --settings=enhydris.settings.local hcore
python manage.py createsuperuser --settings=enhydris.settings.local

The above commands will also ask you to create a Enhydris superuser.

Confused by users?

There are operating system users, database users, and Enhydris users. PostgreSQL runs as an operating system user, and so does the web server, and so does Django and therefore Enhydris. Now the application (i.e. Enhydris/Django) needs a database connection to work, and for this connection it connects to the database as a database user. For the end users, that is, for the actual people who use Enhydris, Enhydris/Django keeps a list of usernames and passwords in the database, which have nothing to do with operating system users or database users. The Enhydris superuser created by the ./manage.py createsuperuser command is such an Enhydris user, and is intended to represent a human.

Advanced Django administrators can also use alternative authentication backends, such as LDAP, for storing the Enhydris users.

Running Enhydris

Inside the openmeteo/enhydris directory, run the following command:

python manage.py runserver --settings=enhydris.settings.local 8088

The above command will start the Django development server and set it to listen to port 8088. If you then start your browser and point it to http://localhost:8088/, you should see Enhydris in action. Note that this only listens to the localhost; if you want it to listen on all interfaces, use 0.0.0.0:8088 instead.

To use Enhydris in production, you need to setup a web server such as apache. This is described in detail in Deploying Django.

Post-install configuration

Domain name

After you run Enhydris, logon as a superuser, visit the admin panel, go to Sites, edit the default site, and enter your domain name there instead of example.com. Emails to users for registration confirmation will appear to be coming from that domain. Restart the webserver after changing the domain name.

Settings reference

These are the settings available to Enhydris, in addition to the Django settings.

ENHYDRIS_FILTER_DEFAULT_COUNTRY

When a default country is specified, the station search is locked within that country and the station search filter allows only searches in the selected country. If left blank, the filter allows all countries to be included in the search.

ENHYDRIS_FILTER_POLITICAL_SUBDIVISION1_NAME
ENHYDRIS_FILTER_POLITICAL_SUBDIVISION2_NAME

These are used only if FILTER_DEFAULT_COUNTRY is set. They are the names of the first and the second level of political subdivision in a certain country. For example, Greece is first divided in ‘districts’, then in ‘prefecture’, whereas the USA is first divided in ‘states’, then in ‘counties’.

ENHYDRIS_USERS_CAN_ADD_CONTENT

This must be configured before syncing the database. If set to True, it enables all logged in users to add content to the site (stations, instruments and timeseries). It enables the use of user space forms which are available to all registered users and also allows editing existing data. When set to False (the default), only privileged users are allowed to add/edit/remove data from the db.

ENHYDRIS_SITE_CONTENT_IS_FREE

If this is set to True, all registered users have access to the timeseries and can download timeseries data. If set to False (the default), the users may be restricted.

ENHYDRIS_TSDATA_AVAILABLE_FOR_ANONYMOUS_USERS

Setting this option to True will enable all users to download timeseries data without having to login first. The default is False.

ENHYDRIS_STORE_TSDATA_LOCALLY

Deprecated.

By default, this is True. If set to False, the installation does not store the actual time series records. The purpose of this setting is to be used together with the dbsync application, in order to create a website that contains the collected data (except time series records) of several other Enhydris installations (see the hcore_remotesyncdb management command). However, all this is under reconsideration.

ENHYDRIS_REMOTE_INSTANCE_CREDENTIALS

If the instance is configured as a data aggregator and doesn’t have the actual data locally stored, in order to fetch the data from another instance a user name and password must be provided which correspond to a superuser account in the remote instance. Many instances can be configured using this setting, each with its own user/pass combination following this scheme:

ENHYDRIS_REMOTE_INSTANCE_CREDENTIALS = {
  'kyy.hydroscope.gr': ('myusername','mypassword'),
  'itia.hydroscope.gr': ('anotheruser','anotherpass')
}
ENHYDRIS_USE_OPEN_LAYERS

Set this to False to disable the map.

ENHYDRIS_MIN_VIEWPORT_IN_DEGS

Set a value in degrees. When a geographical query has bounds with dimensions less than MIN_VIEWPORT_IN_DEGS, the map will have at least a dimension of MIN_VIEWPORT_IN_DEGS². Useful when showing a single entity, such as a hydrometeorological station. Default value is 0.04, corresponding to an area approximately 4×4 km.

ENHYDRIS_MAP_DEFAULT_VIEWPORT

A tuple containing the default viewport for the map in geographical coordinates, in cases of geographical queries that do not return anything. Format is (minlon, minlat, maxlon, maxlat) where lon and lat is in decimal degrees, positive for north/east, negative for west/south.

ENHYDRIS_TS_GRAPH_CACHE_DIR

The directory in which timeseries graphs are cached. It is automatically created if it does not exist. The default is subdirectory enhydris-timeseries-graphs of the system or user temporary directory.

ENHYDRIS_TS_GRAPH_BIG_STEP_DENOMINATOR
ENHYDRIS_TS_GRAPH_FINE_STEP_DENOMINATOR

Chart options for time series details page. The big step represents the max num of data points to be plotted, default is 200. The fine step are the max num of points between main data points to search for a maxima, default is 50.

ENHYDRIS_SITE_STATION_FILTER

This is a quick-and-dirty way to create a web site that only displays a subset of an Enhydris database. For example, the database of http://deucalionproject.gr/db/ is the same as that of http://openmeteo.org/db/; however, the former only shows stations relevant to the Deucalion project, because it has this setting:

ENHYDRIS_SITE_STATION_FILTER = {'owner__id__exact': '9'}

If True, the station detail page shows copyright information for the station. By default, it is False. If all the stations in the database belong to one organization, you probably want to leave it to False. If the database is going to be openly accessed and contains data that belongs to many owners, you probably want to set it to True.

ENHYDRIS_WGS84_NAME

Sometimes Enhydris displays the reference system of the co-ordinates, which is always WGS84. In some installations, it is desirable to show something other than “WGS84”, such as “ETRS89”. This parameter specifies the name that will be displayed; the default is WGS84.

This is merely a cosmetic issue, which does not affect the actual reference system used, which is always WGS84. The purpose of this parameter is merely to enable installations in Europe to display “ETRS89” instead of “WGS84” whenever this is preferred. Given that the difference between WGS84 and ETRS89 is only a few centimeters, which is considerably less that the accuracy with which station co-ordinates are given, whether WGS84 or ETRS89 is displayed is actually irrelevant.