diff --git a/src/openeo_grass_gis_driver/actinia_processing/base.py b/src/openeo_grass_gis_driver/actinia_processing/base.py
index 0b279b54..842ede15 100644
--- a/src/openeo_grass_gis_driver/actinia_processing/base.py
+++ b/src/openeo_grass_gis_driver/actinia_processing/base.py
@@ -385,6 +385,20 @@ def openeo_to_actinia(node: Node) -> Tuple[list, list]:
                 node.get_parent_by_name(
                     parent_name=key).output_objects)[0]
             data_object = value
+            # check schema subtype of parameter and compare with
+            # datatype of data_object
+            if ao["schema"]["subtype"] == "cell" and \
+               data_object.datatype != GrassDataType.RASTER:
+                raise Exception(
+                    "Wrong input data type, expecting 'cell'")
+            elif ao["schema"]["subtype"] == "strds" and \
+               data_object.datatype != GrassDataType.STRDS:
+                raise Exception(
+                    "Wrong input data type, expecting 'strds'")
+            elif ao["schema"]["subtype"] == "vector" and \
+               data_object.datatype != GrassDataType.VECTOR:
+                raise Exception(
+                    "Wrong input data type, expecting 'vector'")
         elif ao["schema"]["type"] == "boolean":
             # flag
             if node.arguments[key] is True:
diff --git a/src/openeo_grass_gis_driver/processes_process_id.py b/src/openeo_grass_gis_driver/processes_process_id.py
index 6e820a7d..bab089d2 100644
--- a/src/openeo_grass_gis_driver/processes_process_id.py
+++ b/src/openeo_grass_gis_driver/processes_process_id.py
@@ -31,8 +31,22 @@ def get(self, process_id):
             iface = ActiniaInterface()
             module = ACTINIA_OPENEO_PROCESS_DESCRIPTION_DICT[process_id]
             module_name = module["id"]
+            # note that this will list all outputs of a module, not the
+            # selected output of the pseudo module
             status_code, module = iface.list_module(module_name)
             if status_code == 200:
+                if "parameters" in module:
+                    for item in module["parameters"]:
+                        if "subtype" in item["schema"]:
+                            if item["schema"]["subtype"] in ("cell", "strds"):
+                                item["schema"]["type"] = "object"
+                                item["schema"]["subtype"] = "raster-cube"
+                if "returns" in module:
+                    for item in module["returns"]:
+                        if "subtype" in item["schema"]:
+                            if item["schema"]["subtype"] in ("cell", "strds"):
+                                item["schema"]["type"] = "object"
+                                item["schema"]["subtype"] = "raster-cube"
                 return make_response(jsonify(module), 200)
 
         return make_response(
diff --git a/src/openeo_grass_gis_driver/register_actinia_processes.py b/src/openeo_grass_gis_driver/register_actinia_processes.py
index 16504771..d6cbd38d 100644
--- a/src/openeo_grass_gis_driver/register_actinia_processes.py
+++ b/src/openeo_grass_gis_driver/register_actinia_processes.py
@@ -28,6 +28,18 @@ def register_processes():
         for module in modules:
             # convert grass module names to openeo process names
             process = module["id"].replace('.', '_')
+            if "parameters" in module:
+                for item in module["parameters"]:
+                    if "subtype" in item["schema"]:
+                        if item["schema"]["subtype"] in ("cell", "strds"):
+                            item["schema"]["type"] = "object"
+                            item["schema"]["subtype"] = "raster-cube"
+            if "returns" in module:
+                for item in module["returns"]:
+                    if "subtype" in item["schema"]:
+                        if item["schema"]["subtype"] in ("cell", "strds"):
+                            item["schema"]["type"] = "object"
+                            item["schema"]["subtype"] = "raster-cube"
             ACTINIA_PROCESS_DESCRIPTION_DICT[process] = module
 
             # create "pseudo" modules which comply to openeo
@@ -37,6 +49,8 @@ def register_processes():
                 # create "pseudo" module for every output:
                 for returns in module['returns']:
                     pm = dict(module)
+                    # TODO: do not change the id, otherwise it breaks
+                    # iface.list_module(pm['id'])
                     pm['id'] = "%s_%s" % (
                         module['id'], returns['name'])
                     pm['returns'] = returns
diff --git a/src/openeo_grass_gis_driver/utils/process_graph_examples_v10.py b/src/openeo_grass_gis_driver/utils/process_graph_examples_v10.py
index 8a32ca47..f98b1e35 100644
--- a/src/openeo_grass_gis_driver/utils/process_graph_examples_v10.py
+++ b/src/openeo_grass_gis_driver/utils/process_graph_examples_v10.py
@@ -786,7 +786,7 @@
                 }
             },
             "compute_slope": {
-                "process_id": "r_slope_aspect",
+                "process_id": "r_slope_aspect_slope",
                 "arguments": {
                     "elevation": {"from_node": "get_elevation_data"},
                     "e": True,