lab4.md

@@ -91,12 +91,12 @@ In `lab3_node`:
 PREFIX gis: <http://www.ida.liu.se/~TDDE05/gis>
 PREFIX properties: <http://www.ida.liu.se/~TDDE05/properties>
   
-SELECT ?x ?y FROM 'salientpoints' WHERE { <someid> a <someklass> ;
+SELECT ?x ?y WHERE { <someid> a <someklass> ;
               properties:location [ gis:x ?x; gis:y ?y ] . }
 ```
 * Take into account the following when calling this query:
   - Make sure to keep `<` and `>` they indicate a URI in the query, without them the query is invalid and will not be executed, so you can replace `<someid>` by `<somethingelse>` but not `somethingelse`.
-  - Replace `salientpoints` with the TST parameter for `graphname`.
+  - set the TST parameter for `graphname` in the parameter to the service call.
   - This query need to be executed with a service call to `/kDBServerNodelet/sparql_query`. You can check the official tutorial for [Python](https://docs.ros.org/en/galactic/Tutorials/Beginner-Client-Libraries/Writing-A-Simple-Py-Service-And-Client.html) or [C++](https://docs.ros.org/en/galactic/Tutorials/Beginner-Client-Libraries/Writing-A-Simple-Cpp-Service-And-Client.html) to learn how to make a service call.
   - In the call to `/kDBServerNodelet/sparql_query`, the fields `bindings` and `service` are unused for this lab and can be set to an empty string.
 * If the object has not been observed yet in the database. Add new observation using the insert triples service call (replace 'salientpoints' with the TST parameter for `graphname`).