topic Re: Aligning GRTS cells in Data Management Questions

Aligning GRTS cells

MatthewRice — Tue, 29 Sep 2015 22:11:31 GMT

So I have 2 separate GRTS (Generalized Random Tesselation Stratified) for spatial sampling that I want to align but am having trouble even after projecting them to the same coordinate system (Projected: NAD_1983_Albers / Geographic: GCS_North_American_1983).

Any suggestions?

Re: Aligning GRTS cells

DanPatterson_Retired — Tue, 06 Oct 2015 23:36:32 GMT

What were the geographic coordinate bounds for both files, prior to the projection? and what were the projection parameters you used for both

Re: Aligning GRTS cells

MatthewRice — Wed, 07 Oct 2015 16:20:03 GMT

Both are the custom projection below

NAD_1983_Albers

Authority: Custom

Projection: Albers

False_Easting: 0.0

False_Northing: 0.0

Central_Meridian: -100.0

Standard_Parallel_1: 55.0

Standard_Parallel_2: 65.0

Latitude_Of_Origin: 50.0

Linear Unit: Meter (1.0)

Geographic Coordinate System: GCS_North_American_1983

Angular Unit: Degree (0.0174532925199433)

Prime Meridian: Greenwich (0.0)

Datum: D_North_American_1983

Spheroid: GRS_1980

Semimajor Axis: 6378137.0

Semiminor Axis: 6356752.314140356

Inverse Flattening: 298.257222101

NAD_1983_Albers

Authority: Custom

Projection: Albers

False_Easting: 0.0

False_Northing: 0.0

Central_Meridian: -96.0

Standard_Parallel_1: 29.5

Standard_Parallel_2: 45.5

Latitude_Of_Origin: 23.0

Linear Unit: Meter (1.0)

Geographic Coordinate System: GCS_North_American_1983

Angular Unit: Degree (0.0174532925199433)

Prime Meridian: Greenwich (0.0)

Datum: D_North_American_1983

Spheroid: GRS_1980

Semimajor Axis: 6378137.0

Semiminor Axis: 6356752.314140356

Inverse Flattening: 298.257222101

Re: Aligning GRTS cells

DanPatterson_Retired — Wed, 07 Oct 2015 16:23:27 GMT

Wow...you central meridians are different and so are your standard parallels, no wonder they look funky. They are definitely not the same ... except for the first 2 lines ... NAD_1983_Albers, Authority: Custom

They are both Custom but that is about it.

Re: Aligning GRTS cells

MatthewRice — Wed, 07 Oct 2015 16:41:07 GMT

I didn't know if I could correct the Canadian one, I end up redrawing the fishnet, the problem was that I wanted to extract the data from the original one into the new grid draw but since the polygons won't be aligned I wouldn't get matching results. I run into the problem below where the IDs get out of order.

Red is original (skewed)

Green is new grid draw trying Spatial Join to match polygons.