What projection should I use to measure in meters?

[CarinaZacharias]

Dear all,

I want to do some distance calculations in ArcGIS, but it is always calculating in degrees. I think the only way to make it measure my distances in meters is to change the data and the data frame to an appropriate projection? (I have set the map properties to meters already.) However, I do not  know which projection to choose. I am looking at an area that is roughly at 31.0309° N, 103.1831° E. I have read somewhere else that UTM is good, but Arc offers so many different UTM projections that I was lost again. I think the UTM grid should be 48.

Is anybody able to suggest a specific coordinate reference system that I can try? Thanks ever so much in advance.

Carina

[JakeSkinner]

Hi Carina,

You are correct that zone 48 is what you should use.  One thing that is helpful is using a utm shapefile.  You will have this utm shapefile located at the following location:

C:\Program Files (x86)\ArcGIS\Desktop10.4\Reference Systems

You can add this to ArcMap and then enter in the coordinates you referenced above.  Take a look at the 'Zone' field the point falls in and you will see that it's 48.

[CarinaZacharias]

Hi Jake,

thanks for the answer! But what confused me was how many different UTM projections there are. If I go to projections in Arc there are many different folders under "UTM". I guess I would go for Asia, since that's where the nature reserve is located that I'm looking at. But even under Asia there are so many that have 48 in it. There is for example "Indian 1954 UTM Zone 48N" or "MONREF 1997 UTM Zone 48N" etc. ... How do I know which one to choose here?

Sorry, if this is a stupid question ...

[JayantaPoddar · Accepted solution]

If I am not wrong,

Go to Projected Coordinate System > UTM > WGS 1984 > North > 48N

[CarinaZacharias]

Okay, I will try, thanks again!

[CarinaZacharias]

Hi, thanks for your help. Unfortunately projecting my data to the UTM Zone 48 reference system didn't help. I also made a complete new map, set the reference system to UTM 48, imported the data - still no difference. The distance is still being calculated in degrees. And if I go to the Properties of my raster layers and to Source and look at cell size I see that these are obviously still in degrees. Do you think that could be the problem?

Does anybody have any more suggestions?

[JayantaPoddar]

You should use Project Raster—Help | ArcGIS for Desktop to reproject your data from GCS to PCS. You should NOT change the spatial reference from layer properties in ArcCatalog.

[CarinaZacharias]

oops, I alwys thought the "define projection" tool was the only way to change the projection. This is good to know although sadly it does still not make a difference ...

[DanPatterson_Retired]

you need to open a new dataframe and add your projected data there... otherwise, the recently projected gets unprojected on-the-fly back to the coordinate system of the dataframe

[CarinaZacharias]

But I did that ...