topic Re: Grid extract (.img) to shapefiles in 911 GIS Questions

Grid extract (.img) to shapefiles

PoojaPandey1 — Tue, 04 Jul 2017 05:06:06 GMT

Having daily rainfall gridded data, now I wish to extract those data to different districts shapefiles. The raster has a label and count. I've tried using zonal histogram and extract by mask but not sure whether they are the appropriate tools or not. Also as data is for 30 years, its time taking to process each every time, suggest any option for this.

Re: Grid extract (.img) to shapefiles

JayantaPoddar — Tue, 04 Jul 2017 07:07:56 GMT

How about a Zonal Statistics as Table—Help | ArcGIS for Desktop followed by Join Field—Help | ArcGIS for Desktop ?

Re: Grid extract (.img) to shapefiles

PoojaPandey1 — Tue, 04 Jul 2017 07:32:47 GMT

I can use zonal statistics but still there are some grids which are crossed by polygons, not the whole grid will be in one polygon, then is it ok to use zonal histogram or statistic or should I go with any other (weighted inverse method) method then continue with it.

Re: Grid extract (.img) to shapefiles

JayantaPoddar — Tue, 04 Jul 2017 08:18:05 GMT

If the center of the pixel is inside the polygon, the pixel would be used for the Statistics calculation. Try the method I stated above and let us know if the result is up to your expectation.

1. Zonal Statistics as Table - Choose only those statistics types that you would like to add to the table.

2. Join Field - Choose only those fields that you would like to add to the polygons.

Re: Grid extract (.img) to shapefiles

DanPatterson_Retired — Tue, 04 Jul 2017 08:43:38 GMT

this sounds similar to one of your previous threads

https://community.esri.com/thread/194121-how-to-count-number-of-overlapped-pixels

Re: Grid extract (.img) to shapefiles

PoojaPandey1 — Tue, 04 Jul 2017 09:45:44 GMT

Thanks that worked. I have 33 years of daily rainfall data, it'll be really a time taking procedure to do this one by one, is there any other option to speed up.

Re: Grid extract (.img) to shapefiles

JayantaPoddar — Tue, 04 Jul 2017 09:52:15 GMT

Use these tools to create a model in model builder using Iterate Rasters—Help | ArcGIS Desktop

Re: Grid extract (.img) to shapefiles

JayantaPoddar — Wed, 05 Jul 2017 08:48:43 GMT

Creation of multiple tables is not a problem, since that is not your final output.

Where did you use the JOIN FIELD tool?

JOIN FIELD tool will add the fields in the same attribute table (of Polygon FC).

And why all input/output are Parameters? Only the input Raster Workspace and the polygon boundary should be marked as parameters (since they would be User Input). The rest can be marked as intermediate, except the final output.