topic Re: Calculating spread of invasive species using ArcGIS for Desktop in ArcGIS Spatial Analyst Questions

Calculating spread of invasive species using ArcGIS for Desktop

MarkWisniewski — Sat, 15 Aug 2015 05:06:46 GMT

I have ArcGIS Desktop Advanced and so far have completed the following;

Used Supervised classification on a satellite image to identify the invasive species with field verification. I have converted the raster to a vector polygon to get the area in hectares.
Used Supervised classification in a second satellite image in the same area with a different time stamp and again converted to polygon to obtain area in hectares.

I would now like to;

Determine the rate of spread for this current period between the 2 satellite images/polygons and;
Use this to predict future spread of the species.

Can anybody offer some suggestions of the workflow to use?

Re: Calculating spread of invasive species using ArcGIS for Desktop

DanPatterson_Retired — Sat, 15 Aug 2015 07:37:55 GMT

As a start...

cell count times cell area = area ... converting to polygon won't make it more accurate

you have determined the difference between the two?

have you calculated the Euclidean difference from 1 boundary to time 2's boundary?

Re: Calculating spread of invasive species using ArcGIS for Desktop

MarkWisniewski — Sat, 15 Aug 2015 08:00:18 GMT

Dan,

The main reason I converted to a polygon was the information is giving to a volunteer community group who are using Google Earth.

No I haven't determined the distance between the two. This is the part I wasn't sure about because as you know, there are more ways than one in ArcGIS to undertake a task.

Re: Calculating spread of invasive species using ArcGIS for Desktop

DanPatterson_Retired — Sat, 15 Aug 2015 09:40:10 GMT

In raster world, a simple Euclidean distance within the spatial analyst will help

http://desktop.arcgis.com/en/desktop/latest/tools/spatial-analyst-toolbox/euclidean-distance.htm

http://desktop.arcgis.com/en/desktop/latest/tools/spatial-analyst-toolbox/understanding-euclidean-distance-analysis.htm

subtracting the images can be accomplished using simple tools

http://desktop.arcgis.com/en/desktop/latest/tools/spatial-analyst-toolbox/minus.htm

It might help if you had a screen grab of both sets of data for an area to facilitate other suggestions. I am sure the situation isn't as simple as 'here it was' ... 'here it is'