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How do I compare spatial references of extents?

KylePerri

I am passing an extent into my script tool and I want to check to make sure it is WGS84 and if it isn't I convert it using projectAs; however, when it is WGS84 if I project it the extent's xmin, xmax, ymin, ymax gets messed up. How can I compare them so I don't project it if it's already in decimal degrees? Here is what I have, but it doesn't seem to work:

boundingBox <SPAN class="operator token">=</SPAN> None
WGS84 <SPAN class="operator token">=</SPAN> SpatialReference<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4326</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token"># Project our extent to GPS lat long if it is not already</SPAN>
<SPAN class="keyword token">if</SPAN> extent <SPAN class="operator token">and</SPAN> extent<SPAN class="punctuation token">.</SPAN>spatialReference <SPAN class="keyword token">is</SPAN> <SPAN class="operator token">not</SPAN> WGS84<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; boundingBox <SPAN class="operator token">=</SPAN> extent<SPAN class="punctuation token">.</SPAN>projectAs<SPAN class="punctuation token">(</SPAN>WGS84<SPAN class="punctuation token">)</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

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Accepted answers

JoshuaBixby

Did you try:

boundingBox <SPAN class="operator token">=</SPAN> None
WGS84 <SPAN class="operator token">=</SPAN> SpatialReference<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4326</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="comment token"># Project our extent to GPS lat long if it is not already</SPAN>
<SPAN class="keyword token">if</SPAN> extent <SPAN class="operator token">and</SPAN> extent<SPAN class="punctuation token">.</SPAN>spatialReference <SPAN class="operator token">==</SPAN> WGS84<SPAN class="punctuation token">:</SPAN>
&nbsp;&nbsp;&nbsp; boundingBox <SPAN class="operator token">=</SPAN> extent<SPAN class="punctuation token">.</SPAN>projectAs<SPAN class="punctuation token">(</SPAN>WGS84<SPAN class="punctuation token">)</SPAN>‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

<SPAN class=""> </SPAN>

Your original code used the is operator, which tests for object identity and not equality. A quick check shows that Esri has implemented equality equivalence with the Spatial Reference class:

<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> SR1 <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>SpatialReference<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4326</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> SR2 <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>SpatialReference<SPAN class="punctuation token">(</SPAN><SPAN class="number token">4326</SPAN><SPAN class="punctuation token">)</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> 
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> SR1 <SPAN class="operator token">==</SPAN> SR2
<SPAN class="token boolean">True</SPAN>
<SPAN class="operator token">>></SPAN><SPAN class="operator token">></SPAN> SR1 <SPAN class="keyword token">is</SPAN> SR2
<SPAN class="token boolean">False</SPAN>
‍‍‍‍‍‍‍<SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

All comments

KylePerri

I ended up doing this:

if extent and extent.spatialReference.linearUnitName == 'Meter':
    boundingBox = extent.projectAs(SpatialReference(4326))‍‍

It seems to work.

DanPatterson_Retired

Then my examples should help if it is an extent object. If it is a string representation of the extent, you may have some parsing to do to get the numeric values

KylePerri

Extent is a parameter in the script tool, but I've been using the current extent of my map.

DanPatterson_Retired

An example.... one file in geographic and one in projected coordinates...

in_fc <SPAN class="operator token">=</SPAN> r<SPAN class="string token">"C:\....\arcpytools_demo.gdb\Can_0_big_3"</SPAN>
desc <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Describe<SPAN class="punctuation token">(</SPAN>in_fc<SPAN class="punctuation token">)</SPAN>
ext <SPAN class="operator token">=</SPAN> desc<SPAN class="punctuation token">.</SPAN>extent
ext<SPAN class="punctuation token">.</SPAN>spatialReference<SPAN class="punctuation token">.</SPAN>name
<SPAN class="string token">'GCS_WGS_1984'</SPAN>

in_fc2 <SPAN class="operator token">=</SPAN> r<SPAN class="string token">"C:\Git_Dan\a_Data\testdata.gdb\polygon"</SPAN>
desc2 <SPAN class="operator token">=</SPAN> arcpy<SPAN class="punctuation token">.</SPAN>Describe<SPAN class="punctuation token">(</SPAN>in_fc2<SPAN class="punctuation token">)</SPAN>
ext2 <SPAN class="operator token">=</SPAN> desc2<SPAN class="punctuation token">.</SPAN>extent
ext2<SPAN class="punctuation token">.</SPAN>spatialReference<SPAN class="punctuation token">.</SPAN>name
<SPAN class="string token">'NAD_1983_CSRS_MTM_9'</SPAN>


<SPAN class="comment token"># ----- now do the comparisons ----</SPAN>
ext<SPAN class="punctuation token">.</SPAN>spatialReference<SPAN class="punctuation token">.</SPAN>name&nbsp; <SPAN class="comment token"># ---- 'GCS_WGS_1984'</SPAN>
ext<SPAN class="punctuation token">.</SPAN>lowerLeft
<SPAN class="operator token"><</SPAN>Point <SPAN class="punctuation token">(</SPAN><SPAN class="operator token">-</SPAN><SPAN class="number token">141.00686645507812</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">41.67692565917997</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="comment token">#, #)></SPAN>
ext<SPAN class="punctuation token">.</SPAN>upperRight
<SPAN class="operator token"><</SPAN>Point <SPAN class="punctuation token">(</SPAN><SPAN class="operator token">-</SPAN><SPAN class="number token">52.61888885498041</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">83.11042022705101</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="comment token">#, #)></SPAN>

ext2<SPAN class="punctuation token">.</SPAN>spatialReference<SPAN class="punctuation token">.</SPAN>name&nbsp; <SPAN class="comment token"># ---- 'NAD_1983_CSRS_MTM_9'</SPAN>
ext2<SPAN class="punctuation token">.</SPAN>lowerLeft
<SPAN class="operator token"><</SPAN>Point <SPAN class="punctuation token">(</SPAN><SPAN class="number token">300000.0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">5000000.0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="comment token">#, #)></SPAN>
ext2<SPAN class="punctuation token">.</SPAN>upperRight
<SPAN class="operator token"><</SPAN>Point <SPAN class="punctuation token">(</SPAN><SPAN class="number token">300020.0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="number token">5000020.0</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="comment token">#, #)></SPAN>

<SPAN class="comment token"># ---- now other properties and test parameters ----</SPAN>
ext<SPAN class="punctuation token">.</SPAN>contains<SPAN class="punctuation token">(</SPAN>ext2<SPAN class="punctuation token">)</SPAN>
<SPAN class="token boolean">True</SPAN>

ext2<SPAN class="punctuation token">.</SPAN>contains<SPAN class="punctuation token">(</SPAN>ext<SPAN class="punctuation token">)</SPAN>
<SPAN class="token boolean">False</SPAN>

ext<SPAN class="punctuation token">.</SPAN>overlaps<SPAN class="punctuation token">(</SPAN>ext2<SPAN class="punctuation token">)</SPAN>
<SPAN class="token boolean">False</SPAN>

ext<SPAN class="punctuation token">.</SPAN>within<SPAN class="punctuation token">(</SPAN>ext2<SPAN class="punctuation token">)</SPAN>
<SPAN class="token boolean">False</SPAN>

ext2<SPAN class="punctuation token">.</SPAN>within<SPAN class="punctuation token">(</SPAN>ext<SPAN class="punctuation token">)</SPAN>
<SPAN class="token boolean">True</SPAN>

<SPAN class="comment token"># ----- from the help</SPAN>
dir<SPAN class="punctuation token">(</SPAN>ext<SPAN class="punctuation token">)</SPAN>
<SPAN class="punctuation token">[</SPAN><SPAN class="string token">'JSON'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'MMax'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'MMin'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'XMax'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'XMin'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'YMax'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'YMin'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'ZMax'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'ZMin'</SPAN><SPAN class="punctuation token">,</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN> snip<SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN><SPAN class="punctuation token">.</SPAN>
 <SPAN class="string token">', '</SPAN>contains<SPAN class="string token">', '</SPAN>crosses<SPAN class="string token">', '</SPAN>depth<SPAN class="string token">', '</SPAN>disjoint<SPAN class="string token">', '</SPAN>equals<SPAN class="string token">', '</SPAN>geohash<SPAN class="string token">', '</SPAN>geohashCovers'<SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'geohashNeighbors'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'height'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'lowerLeft'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'lowerRight'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'overlaps'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'polygon'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'projectAs'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'spatialReference'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'touches'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'upperLeft'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'upperRight'</SPAN><SPAN class="punctuation token">,</SPAN> <SPAN class="string token">'width'</SPAN><SPAN class="punctuation token">,</SPAN>
 <SPAN class="string token">'within'</SPAN><SPAN class="punctuation token">]</SPAN><SPAN class="line-numbers-rows"><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN><SPAN>‍</SPAN></SPAN>

JoeBorgione

Not sure if these links will help or not:

https://community.esri.com/thread/226543-how-to-output-the-values-of-bounding-box-in-spatial-index-using-python

projectAs help

I don't have any experience with projectAs, but I think if you could get the xy's out of the given feature class and then compare their values to a set (or subset) of known values, you should be able to determine if they are DD or something else.

DanPatterson_Retired

can you put in values that you are testing. the code snippet fails since 'extent' isn't defined

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