topic Re: Geo distance calculation GEODIST in SAS Programming

Geo distance calculation GEODIST

ANLYNG — Thu, 12 Apr 2018 12:30:47 GMT

Hi,

I am stucked with this. I need to calculate distance in SAS between 2 set of coordinates. I only got UTM coodinates and

I use geodist function. But is does not create any output on distance and distance2.

Can you help or have some ideas ?

Thanks in advance,

data test_distance;

set all_koordinater;

distance=geodist(GIS_koor_X,GIS_koor_Y,Latitude2,Longitude2)*1000;

distance2=geodist(726021,6272193,726031,6272193)*1000;

run;

GIS_koor_X	GIS_koor_Y	Latitude2	Longitude2
736021,68	6272193,06	731728,9625	6273181,548
737435,51	6274983,35	731728,9625	6273181,548
737221,52	6274654,31	731728,9625	6273181,548
737043,37	6274223,31	731728,9625	6273181,548
747060,37	6274518,13	721728,9625	6273181,548
727043,37	6274223,31	721728,9625	6273181,548
727497,95	6272526,8	721728,9625	6273181,548
727056,14	6273195,25	721728,9625	6273181,548

Re: Geo distance calculation GEODIST

s_lassen — Thu, 12 Apr 2018 12:42:05 GMT

I think that your problem is the coordinates. The numbers should be in degrees, between 0 and 360, what you have is much too high.

Maybe you have the wrong unit.

I assume that your longitudes and latitudes are 10,000 times too big, but it could be something else.

distance2=geodist(726021,6272193,726031,6272193)*1000;

gives a missing value,

distance2=geodist(72.6021,62.72193,72.6031,62.72193)*1000;

gives a distance of 111 meters and 59 centimeters. Is that what you expected?

Re: Geo distance calculation GEODIST

ANLYNG — Thu, 12 Apr 2018 12:45:09 GMT

the unit is UTM coordinates and should be fine. I am not sure if geodist accepts this input?

Re: Geo distance calculation GEODIST

s_lassen — Thu, 12 Apr 2018 13:02:00 GMT

According to the documentation, no. UTM coordinates are not an option. Coordinates can be degrees or radians.

Re: Geo distance calculation GEODIST

SuryaKiran — Thu, 12 Apr 2018 13:09:19 GMT

GEODIST() function cannot use UTM values as parameters. Convert those values to supported values. This function has a 5th argument <Options> (M- Miles, K- Kilometers, D-Degree and R- Radians) and the default will be 'D'. In your case it is interpreting the values as Degrees.

Document :http://support.sas.com/documentation/cdl/en/lrdict/64316/HTML/default/viewer.htm#a003113162.htm

Re: Geo distance calculation GEODIST

s_lassen — Thu, 12 Apr 2018 13:14:21 GMT

If you have SAS/Graph, you can convert to degrees with PROC GPROJECT.

Re: Geo distance calculation GEODIST

michokwu — Sat, 09 May 2020 17:34:35 GMT

I don't think the UTM coordinates can be used in the SAS geodist function, try using the steps below to compute the distance

data test_distance;

set all_koordinater;

Long_diff = Longitude1 - Longitude2
Lat_diff = Latitude1 - Latitude2;
dist = sqrt ( Long_diff**2 + Lat_diff**2 );
distance = dist*0.000189394; * Convert feet to mile;

run;

Re: Geo distance calculation GEODIST

PGStats — Sat, 09 May 2020 20:59:13 GMT

GEODIST is for calculating geographic distances from latitudes and longitudes. UTM coordinates are expressed in meters from the equater (y value) and one of 60 central meridians (x value). So, within a given zone, the distance between two coordinates (in meters) is given by :

distanceInMeters = EUCLID(UTMx_1-UTMx_2, UTMy1-UTMy_2);