Websites with mapping capabilities are very common nowadays. Beginning with government and corporate enterprise sites to private organization's sites (especially connected with travelling), all of them are using various mapping software in order to provide their users with the demanded geospatial data.
Geographic information system (GIS) is an essential component of mapping software. It provides a set of required functions such as spatial data entry, management, analysis and visualization. GeoServer lets you share and publish your GIS resources on the web as web services.
GeoServer is an open source Java software server. It is used for generating, sharing and managing geospatial data. Using open standards, GeoServer publishes data from any major spatial data source.
To host GeoServer, you need the PostgreSQL database extended with PostGIS. This spatial extension adds support for geographic objects, allowing location queries to be run in SQL. With PostGIS extension, PostgreSQL can be used as a backend spatial database for GIS.
So, let’s investigate how to extend PostgreSQL database with PostGIS and deploy GeoServer to Jelastic's environment, in order to work with shared geospatial data.
A. Create environment
Firstly, we need to create an environment as the basis for our application.
1. Sign up for a Jelastic account (if you haven’t done this before) or log into your Jelastic account.
2. Click on the Create environment button.
3. Select Tomcat 7 as your application server and PostgreSQL 9 as a database you want to use. Set up the resource limits for each node and enter your environment name (e.g. geoserver). Confirm the environment creation.
4. In a few minutes your environment will appear on the dashboard.
B. GeoSever Deployment
Now we can proceed to GeoServer software deployment.
1. Open the GeoServer official web-site and download the latest stable release as a web archive.
2. When downloading is completed, extract the archive you have received.
3. Navigate back to the Jelastic dashboard and upload the geoserver.war file, located in the folder with extracted archive content.
4. Finally, select the Deploy to.. button next to the .war file in the packages list and choose the created before environment, in order to deploy the GeoServer app to it.
C. PostGIS Configurations
At this step, we are going to add PostGIS extension for our PostgreSQL database.
1. Open phpPgAdmin for the PostgreSQL database in your environment by selecting the Open in browser button next to it.
2. Log in with the PostgreSQL credentials you have received via email, after the environment was created.
3. Now, you need to create a new database. Do do this, select the Create database button in the opened window.
4. Fill in the form:
- state the name for a new database (in our case, nyc)
- choose UTF8 encoding in the drop-down list
- fill in the other fields if it is required
Click Create button.
5. Choose your newly created database in the expandable list on the left-hand panel and navigate to the SQL tab.
6. Enter the following SQL queries and execute them:
where the attributes are:
- postgis: for PostGIS enabling (includes raster)
- postgis_topology: for Topology enabling
- fuzzystrmatch: fuzzy matching is needed for Tiger
- postgis_tiger_geocoder: for US Tiger Geocoder enabling
Note: Don’t forget to tick off the Paginate results line under the form in order not to get any errors.
That’s all. PostGIS extension is enabled and can be used.
D. Dataset Import
Now, let’s import a PostGIS dump of a dataset to our PostreSQL database. As an example, we are going to use nyc_buildings.zip with a dataset of buildings from New York City.
1. Download nyc_buildings.zip package and extract it. You’ll get the nyc_buildings.sql file.
2. Enter phpPgAdmin for PostgreSQL with your credentials and navigate again to the SQL tab for your database with PostGIS extension (in our case, nyc database).
3. Browse the extracted dataset (e.g. nyc_buildings.sql) on your local computer and upload as an SQL script.
4. Deselect the Paginate results line under the form and Execute the script.
E. Connect GeoServer with Database
Now, we need to connect our GeoServer application with the PostgreSQL database. For this we’ll create a data store for our nyc database.
1. Navigate to the Jelastic dashboard and open the GeoServer environment (select Open in browser next to it).
2. In the opened browser tab, log in with the default GeoServer credentials (admin/geoserver).
3. Then navigate to the Data > Stores menu item in the left-hand panel and click Add new Store line.
4. In the New data source window select the PostGIS - PostGIS Database option.
5. In the appeared New Vector Data Source window, fill in the following fields:
Basic Store Info
Select the cite Workspace from the drop-down list.
Enter the Data Source Name (for example, nyc_buildings) and a brief Description.
PostGIS database Connection Parameters
host - database host can be taken from the Info button
database - name of the database you’ve created with PostGIS extension (in our case, nyc)
user and passwd - credentials to the PostgreSQL you’ve received while creating the environment
Other fields are filled by default, you can leave the initial values.
Also scroll a little bit lower and check if the Validate connections line is ticked. Then press Save.
The connection is established and as a result, you can see the uploaded PostreSQL nyc_buildings in the list of application resources.
F. Publish and Preview Dataset
Lastly, we need to make just a few configurations to publish the dataset (e.g. nyc_buildings) and to make the required geographical object ready to use.
1. New Vector Data Source (saved in the previous step) will appear in the list of New Layers.
Select Publish next to the added layer (e.g. nyc_buildings).
2. In the opened Edit Layer window enter a Title and an Abstract for your resource.
3. Scroll down the page and select Compute from data and Compute from native bounds buttons in the Bounding Boxes configuration block.
4. Then switch to the Publishing tab and ensure the polygon layer style is selected as default.
5. Finally, scroll down to the bottom of the page and select the Save button. The layer is published.
6. Now you can navigate to the Data > Layer Preview menu item.
Here, you’ll see a list of all layers configured in GeoServer with previews provided in various formats for each.
7. Select the OpenLayers button next to your layer (NYC buildings, in our case).
8. As a result, you will see the required geographical object. In our case, this is an interactive map of New York City buildings.
You can use Preview Map to zoom and pan around the dataset, as well as display the attributes of the features. Enjoy!
In such a way, you can add to your sites different interactive maps in a variety of output formats. With GeoServer, you not only just generate nicely styled maps, but you can also share and edit the source of data. Load, publish, style and share geospatial data easily with GeoServer hosted on Jelastic's platform.
Nowadays an incredibly diverse variety of mapping software is available. Please comment below which system is usually used by you to display your spatial information to the world.