DISTPG-570 Updated postgis docs (#413)

modified:   docs/solutions/postgis-deploy.md
	modified:   docs/solutions/postgis-testing.md
	modified:   mkdocs-base.yml

docs/solutions/postgis-deploy.md

@@ -5,11 +5,12 @@ The following document provides guidelines how to install PostGIS and how to run
 ## Preconditions
 
 1. We assume that you have the basic knowledge of spatial data, GIS (Geographical Information System) and of shapefiles.
-2. You need to acquire spatial data. For the following examples, we'll use the same [data set](https://s3.amazonaws.com/s3.cleverelephant.ca/postgis-workshop-2020.zip) as is used in [PostGIS tutorial](http://postgis.net/workshops/postgis-intro/) 
+2. For uploading the spatial data and querying the database, we use the same [data set](https://s3.amazonaws.com/s3.cleverelephant.ca/postgis-workshop-2020.zip) as is used in [PostGIS tutorial](http://postgis.net/workshops/postgis-intro/). 
+
 
 ## Install PostGIS
 
-1. Enable Percona repository.
+1. Enable Percona repository
 
     As other components of Percona Distribution for PostgreSQL, PostGIS is available from Percona repositories. Use the [`percona-release`](https://docs.percona.com/percona-software-repositories/installing.html) repository management tool to enable the repository. 
 
@@ -94,17 +95,17 @@ The following document provides guidelines how to install PostGIS and how to run
           FROM pg_available_extensions WHERE name LIKE 'postgis%' or name LIKE 'address%';
           ```
 
-3. Create a database and a schema to store your data. A schema is a container that logically segments objects (tables, functions, views, and so on) for better management. Run the following commands from the `psql` terminal
+3. Create a database and a schema for this database to store your data. A schema is a container that logically segments objects (tables, functions, views, and so on) for better management. Run the following commands from the `psql` terminal:
 
     ```sql
     CREATE database nyc;
+    \c nyc;
     CREATE SCHEMA gis;
     ```
 
-4. To make PostGIS functions and operations work, you need to enable the `postgis` extension. From the `psql` terminal, switch to the database you created and run the following command:
+4. To make PostGIS functions and operations work, you need to enable the `postgis` extension. Make sure you are connected to the database you created earlier and run the following command:
 
     ```sql
-    \c nyc;
     CREATE EXTENSION postgis;
     ```
 
@@ -114,19 +115,25 @@ The following document provides guidelines how to install PostGIS and how to run
     SELECT postgis_full_version();
     ```
 
-    The output should be similar to the following:
+    The output should resemble the following:
 
     ```{.sql .no-copy}
     postgis_full_version
     -----------------------------------------------------------------------------------------------------------------------------------------------------------------
-     POSTGIS="3.3.3dev 0" [EXTENSION] PGSQL="140" GEOS="3.10.2-CAPI-1.16.0" PROJ="8.2.1" LIBXML="2.9.13" LIBJSON="0.15" LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)"
+     POSTGIS="3.3.3" [EXTENSION] PGSQL="140" GEOS="3.10.2-CAPI-1.16.0" PROJ="8.2.1" LIBXML="2.9.13" LIBJSON="0.15" LIBPROTOBUF="1.3.3" WAGYU="0.5.0 (Internal)"
     ```
 
 ## Upload spatial data to PostgreSQL
 
 PostGIS provides the `shp2pgsql` command line utility that converts the binary data from shapefiles into the series of SQL commands and loads them into the database.
 
-1. From the folder where the `.shp` files are located, execute the following command and replace the `dbname` value with the name of your database:
+1. For testing purposes, download the sample data set:
+
+    ```{.bash data-prompt="$"}
+    $ curl -LO https://s3.amazonaws.com/s3.cleverelephant.ca/postgis-workshop-2020.zip
+    ```
+
+2. Unzip the archive and from the folder where the `.shp` files are located, execute the following command and replace the `dbname` value with the name of your database:
 
     ```{.bash data-prompt="$"}
     shp2pgsql \
@@ -147,7 +154,7 @@ PostGIS provides the `shp2pgsql` command line utility that converts the binary d
     * `nyc_streets` is the table name to create in the database
     * `dbname=nyc` is the database name
 
-2. Check the uploaded data
+3. Check the uploaded data
 
    ```sql
    \d nyc_streets;
@@ -165,4 +172,4 @@ PostGIS provides the `shp2pgsql` command line utility that converts the binary d
        "nyc_streets_geom_idx" gist (geom)
    ```
 
-3. Repeat the command to upload other shapefiles in the data set: `nyc_census_blocks`, `nyc_neighborhoods`, `nyc_subway_stations`
+4. Repeat the command to upload other shapefiles in the data set: `nyc_census_blocks`, `nyc_neighborhoods`, `nyc_subway_stations`

docs/solutions/postgis-testing.md

@@ -23,7 +23,7 @@ population
 To get the answer we will use the `ST_Area` function that returns the areas of polygons.
 
 ```sql
-SELECT ST_Area(geom) / 1000
+SELECT ST_Area(geom) / 1000000
   FROM nyc_neighborhoods
   WHERE name = 'Central Park';
 ```
@@ -33,11 +33,11 @@ Output:
 ```{.sql .no-copy}
       st_area
 --------------------
- 3519.8365965413293
+ 3.5198365965413293
 (1 row)
 ```
 
-By default, the output is given in square meters. To get the value in square kilometers, divide it by 1000.
+By default, the output is given in square meters. To get the value in square kilometers, divide it by 1 000 000.
 
 ## *How long is Columbus Circle?*
 

mkdocs-base.yml

@@ -186,10 +186,10 @@ nav:
           - solutions/backup-recovery.md
           - solutions/dr-pgbackrest-setup.md
       - Spatial data handling:
-          - Overview: solutions/postgis.md
-          - Deployment: solutions/postgis-deploy.md
-          - Query spatial data: solutions/postgis-testing.md
-          #- Upgrade spatial database: solutions/postgis-upgrade.md
+        - Overview: solutions/postgis.md
+        - Deployment: solutions/postgis-deploy.md
+        - Query spatial data: solutions/postgis-testing.md
+        - Upgrade spatial database: solutions/postgis-upgrade.md
       - LDAP authentication:
           - ldap.md
   - Uninstall: