Is this KML file measured in degrees?

Question

I'm working with a KML layer in QGIS. Here is the file:

The KML file:

<?xml version="1.0" encoding="utf-8" ?>
<kml xmlns="http://www.opengis.net/kml/2.2">
<Document id="root_doc">
<Schema name="2963760840" id="2963760840">
    <SimpleField name="timestamp" type="string"></SimpleField>
    <SimpleField name="begin" type="string"></SimpleField>
    <SimpleField name="end" type="string"></SimpleField>
    <SimpleField name="altitudeMode" type="string"></SimpleField>
    <SimpleField name="tessellate" type="int"></SimpleField>
    <SimpleField name="extrude" type="int"></SimpleField>
    <SimpleField name="visibility" type="int"></SimpleField>
    <SimpleField name="drawOrder" type="int"></SimpleField>
    <SimpleField name="icon" type="string"></SimpleField>
</Schema>
<Folder><name>2963760840</name>
<Placemark>
    <Style><LineStyle><color>ff0000ff</color></LineStyle><PolyStyle><fill>0</fill></PolyStyle></Style>
    <ExtendedData><SchemaData schemaUrl="#2963760840">
        <SimpleData name="tessellate">-1</SimpleData>
        <SimpleData name="extrude">0</SimpleData>
        <SimpleData name="visibility">-1</SimpleData>
    </SchemaData></ExtendedData>
    <Polygon><outerBoundaryIs><LinearRing><coordinates>-88.4317405175818,31.6558800962605 -88.431737410907,31.6559161822374 -88.4317340478576,31.6559522520483 -88.4317304294607,31.65598830298 -88.4317265546618,31.6560243350402 -88.4317224234424,31.6560603464253 -88.4317180368385,31.656096335324 -88.4317133937868,31.6561323008421 -88.4317084963772,31.6561682411606 -88.4317033435555,31.6562041562871 -88.4316979352941,31.6562400435163 -88.4316922726381,31.6562759019385 -88.4316863545151,31.6563117297579 -88.4316801819788,31.6563475269666 -88.4316737560565,31.6563832908516 -88.4316670756934,31.6564190214205 -88.4316601419166,31.6564547159601 -88.4316529536625,31.6564903735763 -88.4316455130305,31.6565259933519 -88.431637818957,31.6565615743927 -88.4316298724689,31.6565971139855 -88.431621673566,31.6566326121303 -88.4316132232843,31.6566680670158 -88.4316045205513,31.6567034768459 -88.4315955664119,31.6567388407112 -88.431586360857,31.6567741577097 -88.4315817286416,31.6567915607419 -88.4311466897599,31.6584809674529 -88.4311356263598,31.658529215528 -88.431124815372,31.6585775059521 -88.431114256788,31.6586258378234 -88.4311039516355,31.658674208429 -88.4310938999238,31.6587226186706 -88.4310841005811,31.6587710667524 -88.431074554662,31.6588195526667 -88.4310652631943,31.6588680737005 -88.4310562240697,31.6589166298692 -88.4310474404426,31.6589652202479 -88.4310389101867,31.6590138430485 -88.4310306343658,31.6590624991651 -88.4310226129532,31.6591111858924 -88.4310148459404,31.6591599023285 -88.4310073343821,31.6592086484659 -88.4310000772153,31.6592574234104 -88.4309930754678,31.6593062244489 -88.430986329149,31.6593550524834 -88.4309798382413,31.6594039057101 -88.4309736027451,31.6594527841292 -88.4309720419662,31.6594653415 -88.4309644366008,31.6595394733955 -88.4309570876343,31.6596136241626 -88.4309499950584,31.6596877928994 -88.4309431588736,31.659761979606 -88.4309365790716,31.6598361833805 -88.4309302545895,31.6599104033289 -88.4309241875368,31.6599846394358 -88.4309183768417,31.6600588899053 -88.4309128225048,31.6601331547375 -88.4309075245268,31.6602074339324 -88.4309024839445,31.6602817256786 -88.4308976996953,31.6603560290821 -88.4308931717888,31.6604303450447 -88.4308889012709,31.660504672657 -88.43088488707,31.6605790101229 -88.4308831265363,31.6606132013205 -88.430880160709,31.6606753008115 -88.4308774511835,31.6607374083529 -88.4308749990237,31.6607995248388 -88.4308728042029,31.6608616475637 -88.4308708656675,31.6609237765354 -88.4308691844632,31.6609859108443 -88.4308677605907,31.6610480504906 -88.4308665929691,31.6611101927763 -88.4308656826711,31.6611723394975 -88.4308650296705,31.6612344879487 -88.430864901764,31.6612506351474 -88.4326782034786,31.6612204116202 -88.432897502907,31.6542440681409 -88.4317454858576,31.6541186481987 -88.4317646239949,31.6548099837846 -88.431765521614,31.65484436124 -88.4317663085529,31.6548787413071 -88.4317669858568,31.6549131230762 -88.4317675535255,31.6549475065475 -88.4322256604991,31.6549477172071 -88.4321986103415,31.6558080866836 -88.4317459607727,31.6558078776201 -88.4317433668281,31.6558439941254 -88.4317405175818,31.6558800962605</coordinates></LinearRing></outerBoundaryIs></Polygon>
</Placemark>
</Folder>
</Document></kml>

I've been told that the measurements here are in degrees, rather than feet or metres. Is this true and can you tell from looking at the file

The coordinates in KML are always in degrees. This and all the other information about KML is in the specification https://developers.google.com/kml/documentation/kmlreference#gxcoord. — user30184, Mar 04 '24 at 15:18

score 6 · Accepted Answer · edited Mar 04 '24 at 19:48

KML is an OGC standard where longitude/latitude are in decimal degrees (based on WGS84 ellipsoid) (Altitude is measured in meters from the WGS84 EGM96 Geoid vertical datum, but you don't seem to have 3d data).

So your coordinate are in decimal degrees but for measurement that's a bit more complicated as depending on how you mesure and how your project is set up you can get measurement in meters (or feet) as well as in degree.

For exemple area(geometry) will return an area in in the Spatial Reference System (SRS) of the geometry (so in degrees) while $area respects both the current project's ellipsoid setting and area unit settings and as such could give you meters or feet as well as degrees…

For the "can you tell from looking at the file" (beside knowing that KML has to be in degrees to be valid) if you look at content of <Polygon><outerBoundaryIs><LinearRing><coordinates> you will see coordinate that are consistant with degrees…

Thank you that's helpful! The reason I'm asking is that in https://gis.stackexchange.com/questions/477611/adding-uploaded-polygon-measurement-style-to-kml-file-polygons?noredirect=1#comment779740_477611 , Im wondering wether the problem is the sides are measured in degree coordinates , but the https://plugins.qgis.org/styles/21/ says that: "The layer MUST be in a projected coordinatesystem with either "meters" or "feet" as unit of measurement." — user1592380, Mar 04 '24 at 16:17
Does this mean that to get it working , I have to somehow reproject the KML layer into meters/feet? — user1592380, Mar 04 '24 at 16:19

Is this KML file measured in degrees?

1 Answers1