Aggregate (Spatial Analyst) outputs the same values whatever statistic is requested

Question

I am experiencing a problem using the Aggregate (Spatial Analyst) tool in both ArcGIS Desktop 10.6.1 and ArcPro 2.2.1 to calculate statistics for generalised raster cells.

I have a 1km resolution DEM from which I want to calculate the MAXIMUM cell value within the cells of a 5km raster. The origins of both rasters are the same.

My simple test data set (in Aggregate.gdb) is a 5x5 1km2 elevation grid (ScotDEMCellAOI) with values as follows:

OBJECTID

Value

Count

1

456

1

456

2

459

1

459

3

460

1

460

4

466

1

466

5

488

1

488

6

489

1

489

7

496

1

496

8

499

1

499

9

500

1

500

10

501

1

501

11

507

1

507

12

511

1

511

13

513

2

1026

14

521

1

521

15

522

1

522

16

538

1

538

17

541

1

541

18

544

1

544

19

546

1

546

20

576

1

576

21

580

1

580

22

598

1

598

23

599

1

599

24

600

1

600

Max

600

Mean

520.92

ScotDEMCellAOI

I wish to aggregate these cells to the coincident 5*5 km cell (CellAOI5km).

I populate the Aggregate (Spatial Analyst) as follows:

The output is a single 5*5 cell with the value 496?

I get the same output when I try and calculate other statistics?

Am I doing something wrong?

Aggregate.gdb.zip

SanchoPinto_0-1658283339466.png

JuanLaguna · Accepted Answer

Hi David.

It looks like you set the Cell Factor to 1 and the Environment Cell Size to 5000 (m).

I think if you try setting the Cell Factor to 5, and leaving the Environment Cell Size to the default (or 1000m), you should get the results you're expecting.

The intention of the tool is to produce a coarser (reduced resolution) version of the input raster, with the multiplier specified by the Cell Factor.  In the scenario described above, the input is essentially being resampled to the 5000 m resolution first, before any statistical option is applied.

Hopefully this resolves your issue.

Cheers,

Juan Laguna

Spatial Analyst Team, Esri