topic Re: Showing the values in grids in Mapping Questions

Showing the values in grids

MuhammadhKhalid — Tue, 23 Aug 2016 17:12:54 GMT

Hi everyone,

I have my Rainfall data on points as shown in the following diagram.

I want them to be show in 3km X 3km grids as shown the following diagram.

I also want the values in these grids as shown in the above, (ie - in regular interval like 0-10, 10-20 ) and the area percentage of these values.

Can you please say me what tool I have to use and how to use them.

Any help is highly appreciable.

Re: Showing the values in grids

DanPatterson_Retired — Tue, 23 Aug 2016 17:44:06 GMT

if you have an advanced license, you can do a direct conversion specifying the cell size the same as your interpoint spacing using Point to Raster—Help | ArcGIS for Desktop

if not, you can use Create Fishnet—Help | ArcGIS for Desktop to create square polygons centered about your points, then spatially join the points to the polygon to bring your attributes over.

The classes and symbology, just use standard tools as covered in the help topics

The clipping is the same, but with the raster, you may want to mask out the exterior area to blend in with the background if you choose.

Re: Showing the values in grids

MuhammadhKhalid — Wed, 24 Aug 2016 06:19:23 GMT

Hi Patterson

Thank you for your quick reply. I was able to use the Point to Raster tool. But the out put comes as either 3.40282e+038 or -3.40282e+038. Even though the output layer is shown under the table of content I'm unable to see anything in the work-space. I think there are some problem with the units. But I dont know how to correct it. Can you please help me.

Also if I want the output in 3km X 3km grids whats the value I should give in output cell size field ? I mean do they have to be given in meters as 3000?

Re: Showing the values in grids

MuhammadhKhalid — Wed, 24 Aug 2016 06:55:27 GMT

Following is the data source of my input file to Point to raster tool

Re: Showing the values in grids

DanPatterson_Retired — Wed, 24 Aug 2016 07:39:35 GMT

go the symbology tab for the raster, look at its histogram... what you are seeing is a stretched range... change the symbology so it isn't stretched and do a manual classification to make it look correct.

Re: Showing the values in grids

DanPatterson_Retired — Wed, 24 Aug 2016 07:42:28 GMT

if you want a projected raster, you could do the projection first using the Project—Help | ArcGIS for Desktop tool

Alternately you can use the Project Raster—Help | ArcGIS for Desktop tool on the raster.

My preference would be the first option

Re: Showing the values in grids

MuhammadhKhalid — Wed, 24 Aug 2016 18:50:03 GMT

Following is my symbology and its not changing from streched to others.

If I try to change it to classified it says following message and if I give ok to it, its not changing and again in stretched.

Re: Showing the values in grids

MuhammadhKhalid — Wed, 24 Aug 2016 19:52:18 GMT

Without giving any processing extent I now gave the cell size as 0.05 and I'm getting nice grids and can change symbology. What is the problem for this behavior and what is my cell size for the value 0.05?

Re: Showing the values in grids

DanPatterson_Retired — Wed, 24 Aug 2016 20:06:28 GMT

because your cell size is 0.05 degrees.

when check the symbology, go to the Histogram option to see the real data distribution, never rely on the legend or what the symbology shows to figure out what data values you actually have.

stretched is pretty well useless, unless you know what you are stretching

Re: Showing the values in grids

MuhammadhKhalid — Thu, 25 Aug 2016 11:11:18 GMT

Thank you Patterson

But i don't want the grids in degrees. I want it in 5km x 5km grids. How can I do it?

Re: Showing the values in grids

DanPatterson_Retired — Thu, 25 Aug 2016 11:43:12 GMT

You seem to have missed my previous response...

you want a projected raster, you could do the projection first using the Project tool
Alternately you can use the Project Raste tool on the raster.
My preference would be the first option

The links are in the actual post. Decide what format you want first (ie projection cell size etc) then worry about symbology... it is the least of your worries... I prefer first name as well

Re: Showing the values in grids

MuhammadhKhalid — Thu, 25 Aug 2016 18:15:30 GMT

Oh really sorry about it Dan.

You was greatly helpful. Thank you very much.