Open Cartodb user account and Create new empty map. Click on Data on the Map page and Import a feature dataset.
For the demo, a Point map representing a layer comprising locations of Clay mineral deposit around the country is imported into the map.
See screenshot for data view of the imported feature layer. The attribute fields contain principally the name of the State where the deposit is located – name_1 and the region as well as the PH value measured at each Clay mineral deposit location.
Next is the MAP VIEW showing the Points geographically located in their X and Y positions around the country.
A Bubbles map will be used to illustrate the varying values (Acid – Basic) of PH measurements recorded at the different points around the country.
Click on the Map Layer Wizard icon and press the arrow key to move to Bubbles (cursor finger position).
Inside the Bubbles window, Click the drop down button on Column option and Select the field whose values you need. For the demo, our attribute field is PH. So the Column field is adjusted to ph. (see cursor finger position).
A Bubble map is created symbolizing the different markers according to the value of the PH. The higher the value, the bigger the marker/circle.
Then the Bubble fill is changed to dark blue –see cursor finger position.
A Bubble map is now created as seen in the Screenshot below.
Next we label the markers/Points in the Bubble map.
We decide to label each point with its ph value lying right inside the point.
Click the Map Layer Wizard icon and Select SIMPLE. Inside the SIMPLE window, go to Label Text. Open the drop down list and select the field to label the markers/points with. For the demo, its PH.(See cursor finger position on screenshot)
The Points are labelled with their ph values, but observe that the labels are outside of the points.
In the same window, we changed the fill to blue. Then to adjust the position of the labels, two options are critical.
-Adjust the Label Offset to 0.
– Select Interior in the Label Placement option.
As observed from the screenshot, the labels are now centred inside the markers or points.