Descriptive error message regarding joining of marker data with encoding data

[angiehjort]

Vizabi should make a descriptive error message when there are dimensions in the encoding space that are not in the marker space which are not filtered down to one possible value. So that extra dimensions in the encoding resolve into a constant whether by filtering or by data only having datapoints for one value. So that the data table doesn't have ambiguity.

In the example below "geo" in latitude wasn't filtered down to one value.

Bubble map config that fails:
right now it fails at a later stage with left and right warning message

__data = {
  modelType: "ddfcsv",
  path: "./data/ddf--jheeffer--mdtest/"
};

VIZABI_MODEL = {
  model: {
    markers: {
      bubble: {
        data: {
          locale: "en",
          source: __data,
          space: ["country", "time"]
        },
        encoding: {
          "selected": {
            modelType: "selection"
          },
          "highlighted": {
            modelType: "selection"
          },
          "size": {
            data: {
              concept: "population_total"
            },
          },
          "lat": {
            data: {
              space: ["geo"],
              concept: "latitude"
            }
          },
          "lon": {
            data: {
              space: ["geo"],
              concept: "longitude"
            }
          },
          "color": {
            data: {
              space: ["geo"],
              concept: "world_4region"
            },
            scale: {
              modelType: "color",
              type: "ordinal"
            }
          },
          "label": {
            data: {
              modelType: "entityPropertyDataConfig",
              concept: "name"
            }
          },
          "frame": {
            modelType: "frame",
            speed: 200,
            data: {
              concept: {
                autoconfig: {
                  concept_type: "time"
                }
              }
            }
          }
        },
        requiredEncodings: ["lat", "lon", "size"]
      },
      "legend": {
        data: {
          ref: {
            transform: "entityConceptSkipFilter",
            model: "markers.bubble.encoding.color"
          }
        },
        encoding: {
          color: {
            data: {
              concept: { ref: "markers.bubble.encoding.color.data.concept" },
              constant: { ref: "markers.bubble.encoding.color.data.constant" }
            },
            scale: {
              modelType: "color",
              palette: { ref: "markers.bubble.encoding.color.scale.palette" }
            }
            //scale: { ref: "markers.bubble.encoding.color.scale" }
          },
          name: { data: { concept: "name" } },
          rank: { data: { concept: "rank" } },
          map: { data: { concept: "shape_lores_svg" } }
        }
      }
    }
  },
  ui: {
    //ui
    "buttons": {
      "buttons": ["colors", "find", "trails", "moreoptions", "presentation", "sidebarcollapse", "fullscreen"]
    },
    "dialogs": {
      "dialogs": {
        "popup": ["colors", "find", "moreoptions"],
        "sidebar": ["colors", "find", "size"],
        "moreoptions": [
          "opacity",
          "speed",
          //"axes",
          "size",
          "colors",
          "label",
          "technical",
          "presentation",
          "about"
        ]
      }
    },
    "chart": {
      labels: {
        removeLabelBox: true
      }
    }
  }
};