Question: Why we do not see 'RED' region around some AP's in VisualRF Floor plans?
A brief background on how heat maps are drawn on floor plans
- When we upload a floor plan and size the plan, VisualRF takes a note of the Floor plan size and at back end divide it into smaller grids.
- By default Airwave determines the grid size for each floor plan by dividing the floor area with default grid number and assigns the nearest grid cell size to each floor plan.
- By default the importation wizard allocates 2,500 grid cells to each site based on dimensions including the white space
- When AP’s are placed on the floor plan, based on the transmit power of AP, Airwave calculates the number of grids it can color for each signal value.
Lets see couple of scenario's here:
Scenario 1 : No AP’s has red colored heat map around them
- Lets say All the AP’s has transmit power of < 9 dbm and the grid cell size is 50X50.
- So, when AMP calculates for heat map, as said above, it always looks for how many grids it can color based on signal strength.
- The -45dbm signal strength for these AP’s could be just around 15-25 feet and when it try to look around the AP for the number of grids within the range of 15-25 there are none. So, it would not draw any red region around it.
- Similarly for -55dbm (orange) area, there’s only one grid that covers it. And we can see the slight orange color around the AP when we zoom into the floor plan. As the plan size is big for the screen and we always try to show the AP upfront, and the orange color is kinda behind the AP.
- We can right click on the Floor Plan in building vie and edit the floor plan to reduce the grid cell size manually to a lower value and the red region around the AP would show up for AP's with low transmit power. However, the load on VisualRF will be pretty high as now its has calculate values for more grids than the default value. If a 50X50 grid floor plan is reduced to 2X2 then the number grids increases 25 fold which is 25X2500 which is huge load on VisualRF and AMP.
Scenario 2 : Few AP’s on same floor plan do not show red area
- Lets say we have most of the AP’s on floor 2 having transmit power of 21.5 only few has transmit power of 19.
- Lets say AP1 with transmit power of 16 do not show the heat map and also another AP, AP2 with transmit power of 21.5 do not have red region around them
- Let’s say AP’s with transmit power of 21.5. Then we have -45dbm signal propagate at least 50-60 feet. Then we would have at least 1 50X50 grid on each side of the AP (as AP1), so we were able to see red area for those AP’s.
- However, if the AP like AP2 in below diag is just placed a bit away where the 50-60 feet region around the AP doesn’t cover the complete grids around it. We would not be able to plot the red region with incomplete grid coverage.
- If we show the grid lines on the floor plan using the preferences option and moved the AP2 to the junction of the grids and we would be able to see the red region for the AP2 as well, as the -45dbm signal strength covers atleast 1 grid on all tsides of AP2.
- The another AP on same floor plan has transmit power of 16 which would have -45 dbm signal ranging 40-50 feet and just short of each grid length and hence we were not able to see the red area, however, if we move the AP such that it covers 1 grid on any side of the AP we get the red area propagated to one side of the AP.
- We can reduce the grid size on this floor plan too to lower,but again its memory utilization on visualRF engine would be high.
It’s the large size of floor plan and combination of lower transmit power on AP radio causes the issue for VisualRF not able to plot the red region around them.