diff --git a/src/components/views/messages/MLocationBody.tsx b/src/components/views/messages/MLocationBody.tsx
index 197e751e15..d9131245d1 100644
--- a/src/components/views/messages/MLocationBody.tsx
+++ b/src/components/views/messages/MLocationBody.tsx
@@ -97,6 +97,15 @@ export default class MLocationBody extends React.Component<IBodyProps, IState> {
 }
 
 export function parseGeoUri(uri: string): GeolocationCoordinates {
+    function parse(s: string): number {
+        const ret = parseFloat(s);
+        if (Number.isNaN(ret)) {
+            return undefined;
+        } else {
+            return ret;
+        }
+    }
+
     const m = uri.match(/^\s*geo:(.*?)\s*$/);
     if (!m) return;
     const parts = m[1].split(';');
@@ -104,12 +113,12 @@ export function parseGeoUri(uri: string): GeolocationCoordinates {
     let uncertainty: number;
     for (const param of parts.slice(1)) {
         const m = param.match(/u=(.*)/);
-        if (m) uncertainty = parseFloat(m[1]);
+        if (m) uncertainty = parse(m[1]);
     }
     return {
-        latitude: parseFloat(coords[0]),
-        longitude: parseFloat(coords[1]),
-        altitude: parseFloat(coords[2]),
+        latitude: parse(coords[0]),
+        longitude: parse(coords[1]),
+        altitude: parse(coords[2]),
         accuracy: uncertainty,
         altitudeAccuracy: undefined,
         heading: undefined,
diff --git a/test/components/views/messages/MLocationBody-test.tsx b/test/components/views/messages/MLocationBody-test.tsx
index b38d3864b3..31281bec6a 100644
--- a/test/components/views/messages/MLocationBody-test.tsx
+++ b/test/components/views/messages/MLocationBody-test.tsx
@@ -52,7 +52,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: 48.198634,
                     longitude: 16.371648,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: 40,
                     altitudeAccuracy: undefined,
                     heading: undefined,
@@ -66,7 +66,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: 90,
                     longitude: -22.43,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: undefined,
                     altitudeAccuracy: undefined,
                     heading: undefined,
@@ -80,7 +80,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: 90,
                     longitude: 46,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: undefined,
                     altitudeAccuracy: undefined,
                     heading: undefined,
@@ -94,7 +94,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: 66,
                     longitude: 30,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: 6.500,
                     altitudeAccuracy: undefined,
                     heading: undefined,
@@ -108,7 +108,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: 66.0,
                     longitude: 30,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: 6.5,
                     altitudeAccuracy: undefined,
                     heading: undefined,
@@ -122,7 +122,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: 70,
                     longitude: 20,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: undefined,
                     altitudeAccuracy: undefined,
                     heading: undefined,
@@ -136,7 +136,7 @@ describe("MLocationBody", () => {
                 {
                     latitude: -7.5,
                     longitude: 20,
-                    altitude: NaN,  // TODO: should be undefined
+                    altitude: undefined,
                     accuracy: undefined,
                     altitudeAccuracy: undefined,
                     heading: undefined,