The document describes solving two problems related to summarizing SRTM raster data. The first problem was that rasters were grouped by values rather than individually. The solution created an overlaying grid to represent each raster. The second problem was that gridlines were not centered over the SRTM rasters. The solution involved creating centroid points for each polygon, making an XY event layer from those points, and using it to generate Thiessen polygons centered on each raster.

1. CreatedBy:V. fernandez-Rogers2015
Chase Johnson2015
SRTM withgridlookslike this
Problem:Rastersare grouped byvaluesandnot individual raster.
Solution- Create gridthat overlaysthe individual raster.
(Iwill nottell youhowwe createdthe grid because itiswrongand we couldnot figure outhow to make it correctly.
Insteadwe solvedthe probleminaroundaboutway.)

2. Problem:Gridlinesnotcenteredontopof SRTM Raster.
Solution:Create centroids,Create Thiessenpolygon
Procedure for creating centroidpoints
In the map document, open the attribute table for the polygon feature class.
In the attribute table,navigate toTable Options> AddFieldandadd two new fieldsof type Double.Name one 'Latitude'
and the other 'Longitude'.
Right-click the Longitude field and select Calculate Geometry.
In the Calculate Geometry dialog box, select 'X Coordinate of Centroid' from the Property drop-down menu. Click OK.
Right-click the Latitude field and select Calculate Geometry.
In the Calculate Geometrydialogbox,select'YCoordinate of Centroid'fromthe Propertydrop-downmenu.ClickOK.
Exportto a table.
A. In the attribute table,selectTable Options>Export.
B. Specifyaname and locationforthe newtable.
Make an XY Eventlayer.
A. Navigate toArcToolbox >Data ManagementTools> Layersand Table Views>Make XY EventLayer.

3. B. Addthe newtable (fromstep7) as the XY Table.
C. For the X Field,selectthe Longitude field.
D. For the Y Field,selectthe Latitude field.
E. Name the neweventlayer.
F. Selectthe spatial reference orcoordinate system.
G. ClickOK.
(Optional) Exportthe EventLayerto a shapefile byright-clickingthe layerandnavigatingtoData> ExportData
Create ThiessenPolygon
OpenArctoolbox ---AnalysisTools--- Proximity—Create ThiessenPolygons